Author Archives: Elena Motivans

About Elena Motivans

I've always liked the way that words can sound together. Combined with my love for nature (and biology background), I'm interested in diving deep into different topics- in the natural world even the most mundane is fascinating!

How honey is made and other sweet facts

How sweet is honey, drizzled into tea or on a piece of bread with butter in the morning. Honey is made, painstakingly, by industrious worker bees in an efficient factory-like hive. Incredibly, bees create this tasty treat as their winter food. Luckily for us, they produce more honey than they need and it can be harvested for us to enjoy.

As sweet as honey. Image credits: maxknoxvill

How do bees make honey?

Bees buzz around nearby meadows looking for flowers with nectar inside. Bees can see ultraviolet wavelengths so some flowers have ultraviolet-reflective regions to guide bees to the nectar. Open or flat flowers with a lot of pollen and nectar attract bees. A nice smell or colour also helps.

A daylily in normal, ultraviolet, and infrared light. The “bee guides” are very clear in the center of the flower in ultraviolet light. Image credits: Dave Kennard

Once it reaches a promising blossom, the bee uses its tube-like tongue (called a proboscis) to suck out the nectar. If there isn’t any nectar in that flower, the bee moves along quickly. Time is honey! Bees have an extra stomach just for storing nectar called the crop. They can carry up to 85% of their body weight in nectar or pollen. While they collect nectar, bees pollinate flowers by transferring pollen, which contains male gametes, to the flowers’ female organs, making it possible for many fruits to grow (such as almonds, apples, avocado, berries, cabbage, cherries, chestnuts, citrus, cucumbers, garlic, pumpkins, sunflowers, and watermelons, to name just a few).

Bees attract a lot of pollen while they’re out foraging. Image credits: Kapa65

Nectar is quite watery, and as you know honey is thick and not very runny. Back at the hive, the bees pass the nectar around to other bees mouth-to-mouth until the nectar is thicker. They mix the nectar with enzymes necessary to mature the honey, and then regurgitate it into a honeycomb cell.

The water is further evaporated by the warm temperature of the hive, which is 32-35 °C. Bees fan the nectar with their wings to help make it thicker. When the honey is thick enough, they seal the cells with beeswax.

Why do bees make honey?

Bees make honey so that they have food for the winter when there aren’t any flowers to harvest food from. Bees do not hibernate but stay active and huddle together for warmth. Honey is the ideal food because it provides a lot of energy to the bees; it’s a rich source of carbohydrates. It also stays good for a really long time; as the high percentage of sugar inhibits bacterial and fungal growth. That’s why you can keep honey on the shelf and not in the refrigerator and also why dried fruit and jam stay good for a long time.

Honey all winter long! Image credits: Max Pixel

The honey in your cupboard

Bees make more honey than they need for the winter so beekeepers harvest the extra honey. Bees produce an average of 30 pounds extra per year (that number depends on a lot on weather and pests). The honey can be harvested multiple times per year.

First, the hive is smoked so that the bees are sedated. Then the wax seals are scraped off and the honeycombs are placed in a centrifuge that spins the frames, extracting the honey. The resulting honey is strained to remove any particles. Even after this whole process, the honeycomb remains intact and is put back into the hive. The bees immediately remove the remaining bits of honey and repair any damaged cells.

Comb overflowing with honey. Image credit: hansbenn

Depending on the time of the year and which flowers are available, the colour and taste of honey will be different. Honey can range from white to a dark amber or brown. Darker honey usually has a stronger taste, such as forest or buckwheat honey. The “typical” light golden colour is from clover patches.

Some of the colours of honey… Image credits: stux

Not so sweet

Unfortunately, bees have been struggling recently. One big problem is the loss of meadows full of flowers to make way for intensive agriculture. In the UK alone, 98% of meadows have been lost.

Pesticides also have a huge impact on bees. They can directly kill bees, affect their functioning, and reduce the number of flowing plants. Pesticides are bad for all pollinators, including butterflies, moths, birds, bats, and wasps. Human activity has been responsible for an increase in the prevalence of colony collapse disorder — that is when most of the worker bees desert the hive and leave only the queen and the immature bees.

A few ways to help are to have a lawn with flowers for pollinators instead of a manicured grass lawn. Other ways are to limit pesticide use, buy produce that is pesticide-free, and to buy local honey.

Bees and other pollinators need healthy meadows full of flowers. Image credits: Martin Speck

Enjoy the honey— and think of the bees!

10 fascinating facts about animals

Animals are incredible! There are millions of animal species and they are fascinatingly diverse. Some can fly, swim, or run, and others can crawl, wriggle, or contract to move. Some are massive and others are so tiny that you need a microscope to see them. Some animals have bones and organs like us, some have bodies that are organized in a completely different way. You could find at least one interesting fact about every single animal, but here are just a few facts that are really fascinating.

1. Over 95% of all animal species are invertebrates.

There are 1.2 million animal species discovered on this planet and more than 95% of them do not have vertebral column like us (that’s 1.14 million inverts!). Insects, spiders, worms, starfish, mollusks, and crabs all fall into this category. Invertebrates are incredibly diverse and occur in huge numbers. If you think just of mites (one group out of many invertebrate groups), there are more different species than all of the vertebrate species combined. Only a tiny fraction of living animals are the large vertebrates that we know so well, like birds, snakes, cats, fish….

Invertebrates can be cute too! Image credits: Steve Childs

2. There’s a huge difference between the world’s largest and smallest animals.

While the largest animal on earth is a vertebrate, invertebrates dominate the microscopic world. The largest animal is the blue whale at 30m long (longer than a basketball court) and the smallest animals are rotifers, which are plankton that can be as small is 0.05 mm (not visible to the human eye). Rotifers are 154 times smaller than the smallest vertebrate which is the tropical frog Paedophryne amauensis (and is about the size of a housefly).

A blue whale compared to a human and a dolphin. Image credits: T. Bjornstad

3. Some animals are only female and give “virgin birth”.

Over 70 vertebrate animal species can give birth without fertilization, such as Komodo dragons, hammerhead sharks, lizards, snakes, and sawfish (although most of these also have males fertilizing eggs). Females lay unfertilized eggs that contain only their genetic material. An advantage is that when it’s hard to find a mate, these animals can still produce offspring. A big disadvantage is that the DNA comes only from the females so the species can become in-bred and susceptible to diseases and mutations.

However, there are a few cases where being female is stable and the only option. Whiptail lizards are only female. These lizards escape becoming in-bred by starting with twice as many chromosomes and recombining their sister chromosomes, which maintains genetic diversity. Spider mites are infected with a bacteria that converts their offspring into females. The bacteria can be passed to offspring in eggs but not in sperm so it maintains this female-only species to its own benefit.

“I don’t need a man”— anonymous whiptail lizard. Image credits: Ltshears

4. Octopuses and hagfish have more than one heart!

Animals have such diverse body plans, the heart is just one example of this. Octopuses have one main heart and two smaller hearts that pump blood to the gills. Hagfish have one main three-chambered heart and three pumps that help it to pump blood. An honourable mention goes to the earthworm which has five aortic arches that pump blood through its segments and perform the same job as a heart.

Hagfish might not be pretty, but they have heart. Image credits: Justin

Hagfish might not be pretty, but they have heart. Image credits: Justin

5. Bioluminescence has evolved at least 50 separate times.

Bioluminescence is the ability of a living creature to produce light. We know that it has evolved separate times because it is produced in many ways, such as with the enzyme luciferase and endosymbiotic bacteria. Bioluminescence is produced by fireflies, glow worms, mollusks, centipedes, deep sea fish, and krill.The purpose can be to attract mates, warn or confuse predators, attract prey, camouflage, or to appear larger. Most of these animals live in the deep sea, beyond the reach of the sun’s rays. Bioluminescence has evolved so many times in this deep environment because it provides a huge advantage in finding prey and mates when it is pitch black.

Glow worms add magical light to caves in New Zealand. Image credits: 2il org

6. Some animals don’t age.

Their cells age at a negligible rate and theoretically these animals would live forever or a really really long time if they didn’t get eaten or a disease. They can still die, of course, but even if they are many years old, their cells look about the same as those of a young animal. One example is the immortal jellyfish which can cycle perpetually between its “child” and “adult” forms. The FoxO gene is responsible for this perpetual youth (hey why doesn’t someone make an anti-aging cream out of that). American lobsters never stop growing as adults and even adults can regenerate a lost limb. Their chromosomes have tips that protect their DNA. The mollusk ocean quahog has been found to be up to 507 years old. They have cell membranes that resist cell damage to keep their cells looking young.

I said they could live forever theoretically… Image credits: Roberto Rodríguez

7. 15,000-20,000 new animal species are discovered each year.

At least 80% of all of the animal species in the world have not yet been discovered. At the pace we’re going, it will be another 480 years before the estimated 8.7 million species on earth are discovered. It is true that most land mammals have already been discovered, but there are so many species to be found in the vast oceans and in tropical forests. If you net insects in a tropical forest, you may find lots of new species. On land, most of the species that have not been discovered (or classified) are insects or arachnids.

Tropical forests hold thousands of undiscovered animals— yet another reason to protect them! Image credits: Chemical Engineer

8. African elephants have the longest pregnancy.

Their pregnancy takes 22 months— that’s almost 2 years! Baby elephants are born very developed; they look like miniatures of their parents and can walk shortly after being born. At the other end of the spectrum, some opossums are pregnant for the shortest time of any animal— only 12 to 13 days. However as opossums are marsupials their babies are born immature and have to spend some time in their mother’s pouch to complete their development.

Opossum newborns still need to mature in their mother’s pouch. Image credits: AnimalPhotos

 9. Dolphins and whales were land animals that evolved back to the ocean.

Whales and dolphins evolved from a land carnivore which then evolved a crocodile-like skull and webbed feet and finally became completely aquatic. Their land ancestor, the pakicetus, likely spent most of its time in the water or near its edge. This transition happened 250 million years after animals first inhabited land. They weren’t happy enough on land so they went back into the sea. Actually, they likely switched back to the marine habitat because it was a niche with plenty of food and other resources. Of all animals alive now, whales and dolphins are the most closely related to hippos. Antelope, pigs, and deer are also closely related— they share similar bone structures.

The pakicetus is actually an ancestor of whales! It lived 50 million years ago near the ocean. Image credits: Nobu Tamura

10. Water bears can survive being in outer space!

Tardigrades, known as water bears for their bear-like appearance, are less than a millimeter long. And they can survive almost anything! Temperatures between -272 and 150°C are not a problem. They can survive pressures greater than in the deepest part of the ocean and ionizing radiation. Tardigrades even can survive living in outer space. They need water to survive but when there is no water available they dry out so they have only 3% of their body water left. These little guys can survive like this for 30 years. When water arrives they rehydrate and go on to look for food and to reproduce like nothing ever happened.

One small step for tardigrades, one giant leap for the animal kingdom. Image credit: Katexic Clippings Newsletter

These facts are just the tip of the iceberg! Comment with the craziest animal fact that you know, and be sure to learn more about these fascinating creatures that share the earth with us.

How to grow food with hydroponics

Food production is serious business. A massive quantity of fresh fruits and veggies need to be grown quickly and with minimal resources to feed the planet’s growing population.

Get rid of soil

One way to optimize food growing is to get rid of soil. Although it seems necessary, photosynthesis and growth do not actually require soil at all. Only CO2, water, and nutrients are necessary and soil merely acts as a base, a foundation for the plants.

Hailed as the future of farming, hydroponics delivers nutrients directly to plant roots. Plants grow faster and produce a higher yield because they don’t have to seek out the nutrients in the soil and extract them. This eradicates problems such as weeds, the need for pesticides, and uncontrollable weather conditions such as droughts or floods. It requires a small amount of water, production can be year round, and it can be used in cities or on dry land.

This all sounds great, but hydroponics can be quite expensive, with buying all of the equipment and building greenhouses. The plants and equipment also need expertise to be operated.

Bye bye soil. Image credits: Tess Watson


For classic hydroponics, plants are grown on a medium and nutrients are delivered to the roots through a special water solution. Some examples of produce that are easy to grow this way are lettuce, tomatoes, radishes, celery, cucumbers, berries, melons, grapes, and herbs.

Your salad could be grown in a greenhouse instead of a field. Image credits: Ryan Somma

The plants are grown on a medium, which provides a base, similarly to how soil provides a base for plants. Having good water and air retention is an important feature. Some of the most popular are coconut coir, which is made from discarded husks from the coconut industry. Rockwool is similar to fiberglass but it is not biodegradable and the dust can be hazardous to human health. Clay pellets can be cleaned and reused, but are quite heavy. Growstones are made from recycled glass mixed with calcium carbonate for a lightweight and porous structure, like lava rocks. There are many other options such as sheepwool, rice husks, brick shards, packing peanuts, and perlite.

A huge brick of coco coir. Image credits: MatiasMiika

The types

There are also many different set-ups that can be used with different costs and advantages.

  • Wicking systems are passive and do not use any pumps. A wick (such as a piece of rope) brings the water and nutrients to the plants’ roots. This system is good for small plants that do not require a lot.

How wicking works. Image credits: Kirk Gordon

  • Deep water cultures use a reservoir with nutrient solution, in the which the roots are suspended. A pump supplies oxygen to the roots.
  • With the nutrient film technique, plants are grown in channels with a nutrient solution constantly running through these channels. The roots are not completely submerged in the water and the water is then recirculated.
  • In ebb and flow systems the plant roots are systematically flooded a few times a day with a nutrient solution. Gravity drains the solution away and pumps provide oxygen.
  • Drip systems are used often commercially. The nutrient solution is kept in a reservoir and pumped through tubes to each plant.

In aeroponics, plants roots freely dangle in an enclosed space. A nutrient solution is regularly sprayed on the roots. According to NASA, this system can reduce water usage by 98%, fertilizer by 60%, and pesticides by 100%. The root is aired out and remains dry, which reduces the risk of disease. There is more control over the root system and it is more cost efficient than other systems. Most plants can be grown with aeroponics, with the exception of fruit trees and root vegetables. NASA is leading this research because it has the potential to sustain human colonies on other planets. For human visits to Mars, aeroponics will likely be used because it uses little water and power and results in a high food output per area.

Fancy some space salad? Image credits: Richard Stoner II

 Fish + plants

It’s possible to combine aquaculture and hydroponics into aquaponics. The fish waste provides a food source for the plants and the plants filter and clean the water. Microbes and worms make the system work by converting the ammonia from fish waste intro nitrate, which provides the nutrients for the plants. Without the microbes, the fish excrements would build up and make the water toxic, instead the bacteria break down the toxins and recirculate them. Both plants and fish benefit; fish disease is rare in aquaponic systems and plants are also healthy.

An aquaponic system with catfish. Image credits: Ryan Somma

Green leaf vegetables, roses, and onions do well in this system. Tomatoes, cucumbers, peppers, melons have high nutrient requirements and can only be grown in aquaponic systems with high densities of fish.

Freshwater fish are usually raised in these systems. Tilapia is the most popular fish because it can tolerate crowding and changing conditions. Bluegill, catfish, perch, and cod are also raised this way. The plants are grown with one of the hydroponic techniques.

Tilapia can withstand crowding and changing conditions. Image credits: Bjørn Christian Tørrissen


If you’re a home gardener, it’s not too difficult (or expensive) to create your own simple hydroponic system. It can be as simple as growing an avocado seedling in a glass of water to creating your own nutrient film cultures.

Grow your own avocado plant easily! Image credits: KVDP

Why and how do jellyfish sting?

Ah, beach holidays: sun, water, sand, jellyfish… jellyfish?! It’s true that jellyfish are one thing to watch out for when you are swimming in the ocean. They’re hard to see, quite often nearly transparent, and many species can give painful stings. These stings are used as a defence mechanism and for capturing prey— and they can be dealt with easily to minimize pain.

Jellyfish may also join you for your swim. Image credits: Unsplash

The “why” and “how”

The reaction is intended as a defense response and to capture prey. Jellyfish are carnivorous and use their stingers to capture algae, zooplankton, and crustaceans. Its tentacles contain the weapons used to immobilize prey. Each jellyfish tentacle is packed with thousands of cnidoblasts, which are cells that contain nematocysts. Think of nematocysts as little harpoons full of venom. Touch triggers them to shoot. The stinging thread at the tip of the harpoon inserts itself into the skin and injects venom. The venom is a neurotoxin, which is meant to paralyze prey but is still painful for humans. Jellyfish venoms are complex and contain porins, neurotoxins, and lipids. The porins tear holes in blood cells and trigger an inflammation response in mast cells (cells in the immune system responsible for allergies and anaphylaxis). Some proteins in the venom cause local pain and skin lesions.

How a nematocyst discharges. Image credits: Spaully

Not every sting is equal

The amount of pain really depends on the species— some jellyfish have stronger venom and bigger cnidoblasts. Not all jellyfish have a painful sting. When swimming in a particular area it’s good to familiarize yourself with the types of jellyfish that can be found in that area to have an idea how toxic they are. In particular, look out for box jellyfish and Portuguese man-of-war— they are particularly dangerous. Even a tentacle that is not attached to a jellyfish can sting you. Jellyfish are more common in some months than others, such as in summer months when the water is warmer. Due to human-related changes to the ocean (such as overfishing, ocean warming, pollution), jellyfish are thriving and increasing in numbers, so large blooms are becoming more common.

With these defences in place, it is hard to imagine that any animal would eat jellyfish. Well, as you would expect for a creature that is 98% water and has lots of stingers, it doesn’t have very many predators. In addition to a few other fish, the massive ocean sunfish and sea turtles eat jellyfish. They are immune to the stinging cells and can enjoy a nice jelly dessert.

The huge ocean sunfish enjoys a jellyfish snack. Image credits: U.S. National Oceanic and Atmospheric Administration

If you get stung

Do not panic! Jellyfish stings are very rarely deadly. Okay, now that the not-panicking is out of the way, remove any tentacles that are still on the skin. Do not move much as moving can cause more venom to be released. Use tweezers, a knife, clean sticks or whatever is on hand (such as the edge of an ID or credit card) to remove the tentacles. You can also rinse it with seawater (NOT freshwater) to help get the tentacles off and reduce discomfort. If you happen to have some vinegar with you can pour it on the affected area, it deactivates the stinging cells of most jellyfish. The sting is alkaline so an acid like vinegar neutralizes it.

A minor jellyfish sting. Image credits: Kate Nevens

To relieve pain, you can immerse the stung skin in hot water as heat inactivates toxins. If pain persists, take a painkiller. If there are signs of an allergic reaction such as hives or trouble breathing, then call emergency health services.

Whatever you do, do NOT add fresh water, pee, meat tenderizer, or alcohol on the sting. When there are still pieces of tentacles, these actions either cause the nematocysts to fire more causing more pain, or at best, do nothing.

A Hawaii-based company has recently developed treatments to provide pain relief and even prevention for jellyfish stings. The main researcher involved, Angel Yanagihara, helped long-distance swimmer Diana Nyad to successfully swim from Havana to Key West in 2013. She had previously been prevented from this goal by the dangerous box jellyfish.

There is no reason to be more afraid of most jellyfish then you would be of a wasp or a bee. With the proper precautions, the risks and pain can be minimized and you can enjoy a relaxing vacation.

The different species of Christmas tree – and how to pick the best one

Confession: when I was younger I thought that all Christmas trees are the same species. There are actually many different species and they all have different traits. By learning about the traits of each you can choose the most perfect tree for you!

Here is a run-down on some of the most popular and available types:


Nordmann Fir

Latin name: Abies nordmanniana

Native to: the Caucasus Mountains south and east to the Black Sea

Pros: it has a nice conical shape, the needles stay on the tree for a long time, the needles are a nice color and not sharp.

Cons: on the more expensive side.

Fun fact: its soft white wood is often used for paper production.

Norway Spruce

Latin name: Picea abies

Native to: central, northern, and eastern Europe

Pros: structured pyramid shape, nice smell, easy on the wallet, soft needles

Cons: needles are a bit sharp and can fall off, sticky sap on trunk

Fun fact: the oldest tree in the world, nicknamed Old Tjikko, is a Norway spruce and is about 9,550 year old!

A Norway spruce in the wild. Image credits: Ivar Leidus

A Norway spruce in the wild. Image credits: Ivar Leidus

Silver Fir

Latin name: Abies alba

Native to: central and southern Europe

Pros: nice conical shape, good needle retention

Cons: may not be available at all tree markets, sparse foliage

Fun fact: was the first species used as a Christmas tree.

Silver firs have a striking needle color. Image credits: Hans

The Blue Spruce

Latin name: Picea pungens

Native to: Rocky Mountains in USA

Pros: blue-green color, nice conical shape, very symmetrical, holds needles

Cons: sharper needles

Fun fact: the latin word “pungens” means sharply pointed and refers to the needles.

The blue spruce has a nice natural conical shape. Image credits: USDA-NRCS PLANTS

The Scots Pine

Latin name: Pinus sylvestris

Native to: all across Eurasia

Pros: nice conical shape when young, long-lasting aroma, good needle retention

Cons: flexible branches aren’t good for heavy ornaments

Fun fact: One of the few used as Christmas tree and both Europe and North America.

Others: Noble fir (Abies procera), Serbian spruce (Picea omorika), Stone pine (Pinus pinea), Swiss pine (Pinus cembra)

It’s definitely not just found in Scotland. Image credits: Nova

North America

Fraser fir

Latin name: Abies fraseri

Native to: small area at higher altitudes in southern Appalachians

Pros: dark green soft needles, ships well, excellent needle retention, nice scent, strong branches, compact (good for limited spaces)

Cons: dense foliage not ideal for hanging many ornaments

Fun fact: named after the Scottish botanist who explored the Appalachians in late 18th century.

Christmas trees (including Fraser firs) are usually grown in plantations. Image credits:

Douglas fir

Latin name: Pseudotsuga menziesii

Native to: Western North America

Pros: nice dark green, blue-green color, soft needles, full looking, sweet smell

Cons: weak branches

Fun fact: This tree species is not a true fir and has its own unique species classification.

You probably won’t have a 9-foot-diameter Douglas fir in your living room. Image credits: Anders B. Wilse

Balsam fir

Latin name: Abies balsamea

Native to: across Canada and eastern USA

Pros: soft needles, retains needles well, fragrant, durable

Cons: more expensive

Fun fact: named for the balsam (resin) found in the bark, which was used to treat wounds in the Civil War.

Oh Balsam fir, oh Balsam fir, how soft are your needles. Image credits: Famartin

Eastern White Pine

Latin name: Pinus strobus

Native to: eastern North America

Pros: little fragrance (good for people who suffer from allergic reactions), retains needles

Cons: weak branches, little fragrance

Fun fact: largest pine tree in the USA.

Virginia Pine

Latin name: Pinus virginiana

Native to: Eastern USA

Pros: strong braches, cheap, nice scent

Cons: sharp needles

Fun fact: it has only started being used as a Christmas tree recently.

This pine needs to be mechanical sheared into the cone shape attractive for Christmas tree. Image credits: Famartin

Others: Blue spruce (Picea pungens)- see Europe, Scots Pine (Pinus sylvestris)- see Europe, Eastern Red Cedar (Juniperus virginiana), White Spruce (Picea glauca), Grand fir (Abies grandis), Noble fir (Abies procera), Red fir (Abies magnifica), White fir (Abies concolor), Pinyon pine (Pinus edulis), Jeffrey pine (Pinus jeffreyi)

When you buy a Christmas tree this holiday season, be an informed shopper and choose the one that matches your needs the most.

How to turn your smartphone into a functional microscope

Microscopes are too bulky and expensive for the average person, but you can still explore the intriguing world right below your nose. You can examine cells, see creatures too tiny to be viewed with the naked eye, and see how salt crystals are shaped like minuscule pyramids… and so much more!

Problem solved: it’s easy to turn your smartphone into a microscope for a fraction of the price! The bonuses here are that it is super mobile and you can take photos.

1. Get crafty

For an easy home-made microscope, you can buy a laser pointer and take it apart so that you remove the lens. By attaching it to your phone camera with sticky-tack or as in the video below, you can magnify anything that you want on the go. You can also create a mini-lab at home to view tiny organisms living in a puddle of water with the instructions here.


If you’re feeling inspired, you can make yourself a 10$ stand which can magnify up to 375X. With this magnification, it’s possible to see plant cells and their nuclei.

Or find a friend with a 3D printer for 1000X for 1$ of material costs.

2. Buy an attachment

If you’re not the crafty type, there are portable microscope attachments for smartphones available for purchase, as thin stickers and thicker plastic stick-ons.

Happy microscope-ing!


Venom versus poison: what is the difference?

Some scorpions are extremely poisonous.

Scorpions aren’t poisonous. Image credits: Minozig


Okay, it’s true that some scorpions are deadly but they are not poisonous, they are venomous. It’s a common mistake to call any animal that produces a dangerous toxin poisonous, but there is an important distinction.

The difference is in the way that the toxin is delivered to the victim. Poison is transmitted by being ingested, inhaled, or touched. Venom, on the other hand, is much more specific. It is only injected. Venomous animals have some sort of structure, such as stingers or fangs, that allow for toxins to be injected into another animal. When in doubt, you can use the adjective “toxic” without making any missteps.

Venom can be injected through fangs (here are the world’s largest snake fangs). Image credits: Brimac The 2nd

Both venomous and poisonous animals produce a toxin that harms or kills another organism. However, this distinction is important to make because venom is not necessarily poisonous. It might not cause harm if ingested or touched. Another difference is that poisonous creatures produce toxins constantly and cannot choose whether to be toxic or not, but venomous creatures can usually choose when to administer their venom. But there are also some venomous and poisonous animals that produce exactly the same toxin. For example, tetrodotoxin (10,000 times more toxic than cyanide!) is found both in pufferfish where it is poisonous and in blue-ringed octopuses where it is venomous.

Here are just a few examples of some poisonous and venomous critters:

Some poisonous creatures

  • Poison dart frogs: these 5 cm frogs contain enough poison to kill 20 humans.
  • Monarch butterflies: the caterpillars only eat milkweed and ingest the toxins present in the plants— this makes the butterflies unpalatable to predators.

The monarch’s coloration serves as a warning to potential predators. Image credits: Kenneth Dwain Harrelson

  • Pitohui, blue-capped ifrit, little strikethrush: these are 3 bird species that are endemic to New Guinea, their skin and feathers contain powerful neurotoxins that come from the beetles that they eat.
  • The flamboyant cuttlefish: this flamboyantly colored cephalopod contains toxic acids rendering its meat poisonous.

Some venomous creatures

The box jellyfish is known as one of the most dangerous venomous animals. Image credits: Peter Southwood

  • Box jellyfish: it has been responsible for 5 567 recorded deaths since 1954. Its stingers contain extremely powerful toxins that attack the heart, nervous system, and skin cells, and it is only possible to survive being stung by it if treated immediately.
  • Bees and wasps: you’ve probably been stung by a bee or wasp at some point and are aware of the pain caused by the venom. 
  • Dogfish sharks: unusually for sharks, venom (which is mildly toxic to humans) coats their dorsal spines.
  • European mole: their saliva contains toxins which can paralyze earthworms. The moles then store them alive for a tasty treat later.
  • Tarantulas: although there has not been a recorded human death due to tarantula venom it can be painful (similar to a wasp sting). The spider can inject venom through its bite and some species also have venom on barbed bristles found on the abdomen.

Now you can be precise in your classification of toxic animals— and know which to avoid!

How in vitro fertilization works: from petri dish to womb

Natural fertility drops dramatically mid-30s but more women want to have children later in life. The solution is often turning to fertility therapy, such as in vitro fertilization. Five million babies have already been born this way – half of this number were born just since 2007!

How it works

The first step to in vitro is for the woman to produce eggs. Women are usually given fertility medicine or hormones to get the ovaries to produce multiple eggs. This increases the odds! A lot of these medications are self-injectable and some women receive up to 90 shots in one cycle.

The ABCs of in vitro fertilization. Image credits: OpenStax College

When the eggs are ready but not yet released during ovulation, a hormone is given to the woman to cause the egg to mature. 36 hours later, the eggs are taken out. The patient is given pain medication for this procedure. A very thin needle is inserted through the upper vaginal wall. Using an ultrasound probe inserted in the vagina, fluid is removed from the follicles with gentle suction. The whole process takes about 20 minutes. The egg is then isolated from the follicular fluid and placed in a culture dish packed with nutrients.

This is where the sperm comes in. A sperm sample, from a partner or a donor, is acquired and it is washed and concentrated. This sperm is mixed with the egg to fertilize it. In cases of sperm motility problems, the sperm is sometimes injected directly into the egg. The petri dish with eggs and sperm is moved to an incubator at 37 degrees for 24 hours and monitored.

Sperm being directly injected into an egg. Image credits: Dovidena

The embryos are left to grow for 3-5 days. At this point, the embryos are about 8 cells large. The healthiest are selected to implant in the womb. The embryo(s) are transferred through a thin flexible plastic tube that is placed through the cervix into the uterine cavity. After 5-6 days after fertilization, the embryo “hatches” from its membrane and implants into the lining of the uterus. For older women or women with multiple failed in vitro attempts, a hole might be made in the membrane to help the egg hatch and implant. After the live embryo has been successfully implanted, the rest of the pregnancy generally proceeds like any other.

Don’t count your chickens before they hatch

The rate of implantation is lower for older women so multiple embryos are usually transferred to increase the probability of a pregnancy. If multiple embryos are transferred, it does increase the risk of a multiple pregnancy. Twins and more are common in women who have in vitro fertilization with two or more embryos implanted successfully. In some countries, there’s a limit to how many embryos can be transferred to prevent three or more babies at the same time.

The success of in vitro fertilization also decreases with age: it is 41-43% for women under age 35, 33-36% for women aged 35 to 37, 23-27% for women aged 38 to 40, and 13-18% for women aged over 40. A woman may have to go through several cycles of in vitro fertilization to have a successful pregnancy.

The chance of a pregnancy with in vitro fertilization decreases with age. Image credits: Pexels


One cycle can range from $12000-$17000, though it often takes more than one cycle to become pregnant. Some clinics offer multiple cycle plans and a refund if the treatment is unsuccessful at a higher premium. In addition, medication can cost between $1500 and $7000. Insurance does not usually cover in-vitro fertilizations, although the costs are covered in some countries with public healthcare.

To save costs, a woman can choose to have extra embryos frozen. If the first implantation is unsuccessful, the frozen embryos can be thawed out and implanted. This way the beginning of the procedure doesn’t have to be repeated and it is less expensive. This has a lower success rate: 37.2% of frozen embryos resulted in a live birth while 56.6% of fresh embryos did. Using frozen embryos may slightly increase the risk of miscarriage.

The risks of in vitro fertilization

All these artificial procedures, such as freezing and thawing, the petri dish environment, and medication and hormones, may harm the gametes and embryos and have lasting effects. The main risks for children conceived this way are birth defects and epigenetic disorders. In addition, the risk of a multiple pregnancy, a premature delivery, and a low birth weight is higher with in vitro fertilization. There has also been speculation about women passing on infertility to their offspring. The most invasive form of in vitro fertilization, when one sperm is injected directly into an egg, can pass abnormal genes to future children. It can also pass on male infertility. The first “test tube baby” was only born in 1978 so there have not been any long-term studies yet.

In vitro fertilization looks poised to become even more important as the late-pregnancy trend continues. There are many exciting opportunities and risks that are associated with this procedure.

Chinese laws are fuelling animal testing for makeup

In 1933, a mascara called Lash Lure caused women to develop massive ulcers leading to blindness and even death for one unlucky woman. After that incident, the safety of makeup was strictly regulated. Animal testing has been used to test the safety of these products, but it is becoming unnecessary as accurate and cruelty-free methods are being developed instead. Many countries have already banned this practice, but China still requires animal testing for makeup that is sold in the country. This requirement is fuelling animal testing worldwide.

The scoop on animal testing

When a cosmetic company wants to use a new ingredient, they need to test it to make sure that it is safe for human usage. Over the past century, animal testing has been primarily used to see to test ingredients. No, it doesn’t involve giving a mouse a makeover. Chemicals are rubbed on shaved skin or dripped into eyes to test for irritation responses. The animals are conscious and given no form of pain relief during this treatment. These tests can result in blindness, sores, bleeding and death for the animals. When the test has been finished, all animals are killed.

Rabbits, guinea pigs, mice, rats, and hamsters are most commonly used for these tests. Image credits: Wikimedia Commons

Does it even work?

These tests are controversial because they inflict pain on the animals and the tests are often not applicable to humans. Since a mouse or rabbit is not the same as a human they often do not have the same response to chemicals. For example, allergy tests on guinea pigs can only predict the human reaction 72% of the time.  Alternative (animal-free) methods are now being developed and used for testing new ingredients.  These methods include using cultured human cells or donated human skin. Advanced computer modelling and studies with human volunteers are also used. Allergy tests are 90% accurate and other alternative tests are also more accurate than animal testing. There are also many already approved ingredients that can be used in makeup without testing on animals.

Guinea pigs do not have the same reactions to chemicals as humans. Image credits: National Cancer Institute

China: the black sheep

More and more countries are banning animal testing for makeup. The list includes the EU, Norway, Israel, India, Turkey, New Zealand, and South Korea. Most other countries don’t have bans but do not explicitly require animal testing. There is one exception. China requires animal testing for all cosmetics that are sold in the country.

Sometimes post-market tests are conducted on makeup without consulting the importing company. Therefore no product sold in China can be deemed animal testing free. This law is in place because the new methods for testing products are not recognized in China. Approximately 300,000 animals a year are used for cosmetic testing in China.

China’s beauty market is the 4th largest in the world, and makeup companies want to get a slice of this profit. Many companies that were previously against animal testing have switched their practices to be able to sell their goods in China. For example, Avon was cruelty-free since 1989 but permits testing again in order to sell to China. All Estée Lauder brands, Burt’s Bees, Mary Kay Cosmetics, and Yves Rocher have also allowed animal testing to enter the Chinese market. However, some companies, like Lush, the Body Shop, Urban Decay, have not entered China for this very reason.

A guide to China’s animal testing laws. Image credits: Ethical elephant

Not all that glitters is gold

The major beauty companies that sell worldwide have to create different product lines for China and the countries that ban animal testing. These companies still test on animals, but the products that you buy in a country where animal testing is banned should not be tested on animals.

However, earlier this year PETA UK discovered that nine major beauty companies were selling the same products in Europe and China. The products were tested on animals to be sold in Chinese stores, but they were illegally placed on the shelves in Europe too. Benefit, Bliss, Caudalie, Clarins, Clinique, Dior, Estée Lauder, and Gucci were all implicated.

Are these lipsticks cruelty-free? Image credits: aleksandra85foto

China’s law is causing companies to take a step backwards and continue to test on animals. This also makes buying cruelty-free products more treacherous for consumers. However, it’s still possible to buy makeup that is certified as animal testing free. The Leaping Bunny is the only internationally recognized certification for cosmetics, personal care products, and household cleaners. To be certified, companies must prove that they do not test on animals and their entire supply chain is audited. Here is another list of cruelty-free makeup brands. It’s still possible to look good without causing any animals to suffer.

That’s probably not cod that you are eating

There’s a lot to gain from slapping the wrong label on seafood. The root of the problem is that we’ve been overfishing our oceans and the result is a deficit of fish. Nonetheless, there is a massive demand for seafood around the world. Most seafood is imported to keep up with demand. There aren’t enough of the commonly eaten fish so fishers take other, less commercially appealing, species and pass them off for one of the more demanded types of fish. This problem is further augmented by high profits from fish fraud and very little law enforcement.

Can you tell which fish these fish sticks are made out of? Image credits: Superbass

When the scales, head, and fins are removed it’s really hard to tell which species a fish fillet is just by looking at it. It’s even trickier when a breaded crust or sauce is added. In this way, it’s quite easy to pass one fish off for another. A lot of fish are chopped into fillets in a built-in factory right on the boat. The fillets arrive to shore frozen in boxes so the secondary buyers might not even know what type of fish they are buying. Indeed, the fraud can occur at any point down the line; the fisher, processor, distributor, and final seller can introduce fraud at any point. Right now, it is impossible to keep tabs on all of the fishing in the world.

How common is it?

Studies that have identified a variety of samples from markets and restaurants have found that at least 1/3 of samples that were tested are not the fish that they were supposed to be.

Sushi restaurants are particularly notorious. In an Oceana study researchers found that 74% of sampled sushi was mislabeled. Even worse, 95% of all tested sushi restaurants were found to be guilty of selling mislabeled fish. And perhaps you shouldn’t order “yellowtail” sushi anymore- none of the restaurants tested served real yellowtail. It’s not that sushi restaurant owners are necessarily trying to cheat you out of a proper sushi dinner; they could be completely unaware and even cheated themselves by their supplies.

A smorgasbord of different fish. Image credits: DesignNPrint

Oceana has a world map in which you can view your country, or city, to see how common fish fraud is in your area.

Watch out for Red Snapper

The most popular fish to buy, such as red snapper, wild salmon, and Atlantic cod, could be mislabeled as much as 25-70% of the time! So be aware when you buy that frozen cod filet. Red snapper is often replaced by Rockfish, Malabar Blood Snapper, and slender Pinjalo. Atlantic cod is often replaced by Whiting, Pollack, Saithe, Oilfish, and Escolar. Escolar, also known as butterfish, is known for being quite tasty, however eating a large piece results in a trip(s) to the bathroom. Groupers are often fraudulent because there are 64 species that can officially be sold as grouper, so it’s easier to sub in another species without getting caught. Grouper is often replaced by catfish, Alaska Pollock, tilapia, and Nile perch. There are numerous other fish species that are substituted for the commercially familiar and favoured fish species. For instance, monkfish is sometimes replaced by pufferfish, which is toxic.


You might think that you are eating anchovy… Image credits: Paul Asman and Jill Lenoble

You might be eating icefish instead. Image credits: Valerie Loeb

You might be eating icefish instead. Image credits: Valerie Loeb

$25 billion + down the drain

The main consequence of fish fraud is that the consumer is getting cheated and doesn’t really have a way to verify what he/she is actually eating. It has been estimated that 25 billion dollars are being lost just in the US each year from fish fraud alone! Those losses seem really high for a bunch of mislabeled fish, how can that be?

Well, the sheer volume of fish involved, we’re talking millions of pounds, and losses at all levels really add up. These losses can come from evading inspection fees, permits, and tariffs. In just one example, Vietnamese catfish was sold as grouper to evade 63 million dollars worth of tariffs in 2010. It is estimated that at least 10 million pounds of catfish are sold as grouper in the U.S. in one year. The incentive? A grouper dinner plate costs on average 25$, while catfish, especially ones from Vietnam that have banned antibiotics in them, sell for much less.

A tasty grouper fillet (or is it?!) for dinner. Image credits: Visit St. Pete/Clearwater

More losses come from deceitful packaging. Some seafood suppliers add more breading, ice, or conserving agents to make up for including less of the actual fish. Some fisheries soak their filets to make them appear larger and heavier when they really just contain more water. Up to 40% of the weight of many seafood products is actually ice.

A threat to human health

Fish can contain contaminants, toxins, and allergens. They cause the most food poisoning outbreaks of any other food group. When there is a lack of accurate information about the fish being consumed, the consumer can be vulnerable to a number of nasty health problems.

Almost all fish contain some mercury, but some can contain levels that are not suitable for children or pregnant women to eat. They can also contain harmful bacteria that cause food poisoning. Ciguatera is a type of food poisoning that is becoming more common. It is from large imported reef fish. It results in symptoms that can last for weeks, including nausea, diarrhea, weakness, and reversed temperature sensation.

Aquaculture fish are often passed off for wild-caught because of the much higher price tag. However, cultured fish often contain high amounts of antibiotics and dyes. Additionally, fish farms in Asia have looser regulations than in other parts of the world and fish are often farmed in polluted rivers and given antibiotics that are banned in many other countries.

Farmed fish are sometimes sold as “wild-caught”. Image credits:

Issues for conservation

When illegal fishing makes such a huge profit it is difficult to implement conservation measures. Illegal fishing practices occur in spite of restrictions or bans on areas or endangered fish species. Unfortunately, it’s hard to monitor fishing practices at sea; it’s almost impossible to know about violations and enforce rules.

It’s impossible to know about all the fishing that goes on in the whole world. Image credits: NOAA Photo Library

Because there appears to be unlimited supplies of breaded cod and tuna sushi, consumers have a misconception that fish are more abundant than they actually are. Consumers can’t make an informed choice because they cannot be sure of what they actually buy.

Moving towards traceability

One way to improve this problematic situation is to introduce a traceability system that tracks the fish throughout its journey from fishing boat to factory to store. Norpac, the fish export company, has developed its own tracking system that traces the fish to the end buyer. There are some other small-scale versions of traceability, but nothing is widely implemented yet. However, more and more consumers are demanding to know where their seafood is from and some large grocery retailers have started to switch to traceable seafood. The real change needs to come at a governmental level. The U.S.A. and EU have made some changes to improve traceability, but so far there are no plans for a comprehensive tracking system.

Another option is to have more rigorous inspections of imported seafood (right now inspections are minimal in most countries). Using DNA barcoding or qPCR probes you can identify the species by its DNA from a small piece of tissue. There are a few portable devices, such as GrouperCheck, that let you check if a piece of fish is a grouper. Theoretically, you could bring the device to a restaurant and check if the fish that you received is actually a grouper. Your dinner might get cold, though, it takes 40 minutes for the sample to be processed. There is a kit for red snapper that claims to test the sample in 20 minutes.

Whole fish are much easier to identify- like this red snapper. Image credits: Geeklikepi

As a consumer, there are a few ways that you can protect yourself against fish fraud. You can buy a whole fish instead of a cryptic fillet. The entire fish is much easier to identify. You can avoid buying the fish that are more commonly falsified, like red snapper, grouper, and Atlantic cod. Fish that are not imported from somewhere else are usually held to higher internal standards and safer to buy. It is important to gather as much information as possible about the fish that you buy!

Hibernation isn’t for the faint of heart

The leaves are falling from the trees, and temperatures are getting colder. As you brace yourself for the winter and snuggle up inside with a blanket, animals are also preparing themselves for the big freeze.

A typical winter scene, with not much food to be seen. Image credits: Public Domain Pictures

Normal activities, like searching for food and avoiding predators, take up lots of energy. Even keeping body temperature constant and digesting food uses energy. In winter, it’s harder to find food in areas at northern latitudes. There aren’t many plants, nuts, or other creatures around that could be a meal. The solution? For animals to decrease their energy requirements so much that they don’t need to be active in winter months. This state is called hibernation.

What is hibernation?

Hibernation is not sleep

Sometimes hibernation is referred to as a “deep sleep” but this is completely inaccurate. When sleeping, the brain is resting for a large part of the time. Body temperature, breathing, and heart rates vary but not to a large degree. Hibernation is more of a suspended animation. In hibernation, the brain never rests – it exhibits that same activity as an awake brain but with suppressed activity. Crazily enough, animals that rise from hibernation show signs of sleep deprivation and often have to sleep for days to be rested.

Hibernation is defined as a sustained period of a body temperature, metabolism, and breathing rate drop. It is essentially a coma-like state that can’t be woken up from easily.

Getting ready

First, animals eat lots of extra food to build fat stores for hibernation. This fat will feed the animal the whole winter so there has to be enough! Bears increase their calorie intake from 8,000 a day to 20,000 a day when preparing for the winter. This energy is stored as white and brown fat. Brown fat is a special type of fat that produces heat more efficiently than white fat. Animals use up the brown fat very slowly and it provides a quick shot of the energy to the animal when it arises from hibernation in the spring. Some animals take snacks with them when they hibernate, so they collect this food in the fall as well.

Next, animals need to find shelter to pass the winter in. They choose a place that is protected from the cold weather, such as a cave, burrow, or hollow log.

Looks cozy to me! Image credits: Pixabay

Different cues signal the right time to start hibernating. These cues depend on the animal, but low outdoor temperatures, short days, internal clock cues, or low available food supplies can trigger the start of hibernation.

Which animals hibernate?

Bears don’t hibernate!

Funny, this is the first animal that comes to mind when most people think about hibernation, but bears are not true hibernators. True, they do hunker down for the winter and their vital signs decrease. However, they don’t decrease their body temperature very much and they wake up easily without negative repercussions. However, bears are often classified as hibernators because they have similar behaviour and it’s easier to group them this way.

Bears are not true hibernators. Image credits: debbiedejager

Then who does?

Usually, smaller animals hibernate because they have higher energy requirements and their insulation (fur, skin) is not warm or thick enough to survive outside the whole winter. Many different animals hibernate, such as frogs, fish, turtles, and snakes. Numerous small mammals also hibernate, including skunks, chipmunks, hedgehogs, squirrels, mice, and bats. There’s even one bird that hibernates, the common poorwill.

The only bird that hibernates is the common poorwill. Image credits: Connor Long

How low does it go?

Hibernation completely changes these animals’ routine. First of all, many hibernators don’t eat or drink at all. Therefore they don’t poop or urinate. The urea from pee is broken into amino acids and recycled in the body. The animals don’t get dehydrated because they get what they need from stored fat.

Because animals don’t do much when they hibernate, cells don’t require the same energy. Therefore they don’t require as much oxygen and the heart doesn’t need to pump blood as often.

Animals who hibernate undergo some serious changes.

  • Breathing rates drop 50-100%.
  • Heart rates between 3 and 10 beats per minutes are typical.
  • Metabolism drops to 2% of the normal rate.

Now for some examples of these extreme lows in actual animals. The box turtle doesn’t breathe at all, but does absorb some oxygen through its skin. Its heart beats only once every 10 minutes. Bats breathe once every 2 hours and their heart beat drops from 1000 beats per minute to only 25. The chipmunk’s heart rate decreases from 200 beats per minute to 5. Hedgehogs breathe only once every 3.5 hours!

The mammal that breathes the least often during hibernation. Image credits: Tony Wills

Some animals undergo even more extreme changes. Yes, even more extreme than not breathing for 3 hours. The body temperature of the arctic ground squirrel goes below freezing. Because of this temperature stress, it loses bone density, brain tissue, and even teeth. But in the spring, it grows all of these back like nothing ever happened. The lungfish encases itself in a mucus sleeve, in which it can survive 3 years without water. It breathes through a little hole- pretty incredible!

One of the few fish that can breathe air can also survive for up to 3 years without water! Image credits: Joel Abroad

Other flavours of hibernation

  • Estivation: The reverse of hibernation, animals that estivate escape hot, dry weather in an inactive state. For examples, some reptiles, amphibians, molluscs become still and their breathing slows during hot months.
  • Brumation: Like hibernation but for reptiles. It is triggered by cold weather and shorter days. Reptiles require water during their brumation.
  • Torpor: the entry of an animal into a state of inactivity and decreased body temperatures. Hibernation is encompassed by this definition but it’s not necessarily long-term; an animal might go into torpor for a few hours to save energy.

Who knew that hibernation was so extreme! Perhaps you’ll appreciate your indoor heating and food from grocery stores a bit more this winter.

The Survivors: Living Fossils That Have Been Around for Hundreds of Millions of Years

The age of dinosaurs seems like a distant, foggy past that is far removed from our current time. We imagine giant lizards, massive scary sea creatures, and a moss and fern dominated landscape that almost seems like another planet it is so different from our own. Although they probably won’t appear in Jurassic Park, the ancestors of all of the animals that live today coexisted with the fearsome dinos. When dinosaurs started dying out approximately 65 million years ago, these animals were somehow able to survive. Most of these survivors evolved and diversified to form all of the biodiversity on the Earth today. However, some animals have remained pretty much the same for millions of years, hence they’re called living fossils. 

The Survivors

1. Coelacanth: This is one old fish; it was thought to have gone extinct with the dinosaurs until a living one was discovered in 1938. These fish live at depths of up 700 m and can grow up to 2 m long. 


This fish was thought to be extinct for 65 million years! Image credits: smerikal

2. Nautilus: These mollusks have stayed more or less the same for the past 500 million years. They are cephalopods, like octopuses and squid, but with a simpler brain.

An ancient mollusc that lives in the open sea. Image credits: Manuae

3. Frilled Shark: These sharks, named after the appearance of their gills, are thought to be a source for legends about sea serpents. Sharks, in general, are a very old group that has been around for 450 million years.

Sharks have been roaming the seas for a really long time. Image credits: Mario Sánchez Bueno

4. Horseshoe crab: Although not actually crabs, these arthropods have existed for 450 million years. Their blood has special bacteria-detecting properties used in human medicine.

One of the most primitive animals in existence. Image credits: Amada44

5. Platypus: The platypus is older than it looks; they have been dated back to 122 million years. Other mammals were alive and well then too (including our human ancestors) but the evolution of monotremes (egg-laying mammals) is much slower than other mammals, which means that they have not changed much in the past millions of years.


The cute, but evolutionary primitive montremes have existed largely unchanged for millions of years. Image credits: Klaus

6. Crocodiles: here is one large reptile that managed to survive what the dinosaurs didn’t. Crocodiles were much larger then than they are now. They likely managed to survive because of their low food requirements and ability to seek refuge in the water. Crocodiles as a group are 240 million years old, making them one of the oldest living fossils.

Crocodiles have been around for millions of years. Image credit: Pixabay

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How environmental DNA is revolutionizing biodiversity research

As you probably know from crime television shows, humans leave their DNA everywhere and forensics are a way to trace it back to the perpetrator of the crime. In a similar way, every living creature leaves traces of their DNA in the environment as their own genetic fingerprint. Spider webs and pee in the snow can reveal the identity of spiders and wolves without having to see the living creatures at all. Read on to find out how!

How it works

This DNA can come from shed skin, excrement, bodily fluids, and other sources from the host. The DNA is left in the environment, so it’s called environmental DNA, or eDNA for short. For fish, this is in the lake that they swim in and for millipedes it is in the soil. Water and dirt are the most common sources for eDNA. However, it can also be found in a number of other sources including snow, sediment, even air.

Every animal has bits of DNA that are different from any other animal — these parts give them their special characteristics. Since no other creature has the same DNA, this a unique tag identify each one. These unique DNA tags are targeted in eDNA detection.

All of the information needed to identify the inhabitants of a lake is in a glass of water. Image credits: Ryan Hyde

First, an environmental sample is taken and then brought to a lab for molecular analysis.

There are two ways to analyze these samples.

1. For a particular animal:

Target a unique DNA tag for that animal. The result is either “yes” or “no” that the animal is there.

Why? to see if an endangered or invasive animal is in an area.

2. For all animals in an area:

Target a part of DNA. Since there is no specific tag, there will many different combinations within this part of DNA. With special software you can match each combination to the species that it is unique to. Therefore, researchers can find the identity of every species in a particular area.

Why? to get a picture of all the animals that live in an area.


DNA is the key to this method. Image credits: Vitaliy Smologin


Biodiversity studies are extremely important because knowing which animals are in an area affects management and conservation goals. These studies, especially with invertebrates, quite often discover new species.

Traditional biodiversity sampling involves catching fish, bugs, or animals by using nets or traps. Then the species are identified by their appearance. The advantages of eDNA over such practices is that it is very quick and cheap. In addition, researchers can check if an animal is there even if it is difficult to tell by any other method. For example, invasive or endangered fish are usually difficult to catch because there are so few of them. Environmental DNA detection can still detect the presence of just a few organisms.

Experts can even have difficulty identifying tiny invertebrates by their appearance. For these small critters, the eDNA approach can be more accurate than trying to identify the species by sight. All in all, this detection method has great applications for conservation and finding new species of animals.

What are other possible applications?

The possibilities of this method for revealing biodiversity are limitless. One example is that by collecting spiderwebs, the identity of spiders and their prey can be determined. In another application, carrion flies (they feed on animal carcasses) were collected in Africa, but not to find out any information about the flies themselves. They were collected because they contain DNA from animals that they fed upon. Because of this, the researchers were able to find out which mammals were present in the region. Similarly, in the Ai Lao Shan Nature Reserve in China, researchers are using animal DNA found in leeches to map wildlife populations in the park.

It is possible to ID a spider and its prey simply based on DNA traces left on the webs. Image credits: Shenrich91

“Yellow snow” is actually useful for determining which species, and even which individual, of a wild wolf population has urinated in that area. Also, saliva on twigs has been used to identify deer species. With all these possibilities, it is easier than ever to non-invasively get a picture of local diversity and track animals of interest.

The limitations

The main limitation of using eDNA is that you only ever see the DNA evidence and never the animal. DNA can come from many other sources not associated with the animal (such as dead animals, feces, and so on). For instance, DNA could be brought to an area by wind, a river current, or an animal. Alternatively, a mistake could occur in the analysis, detecting an animal that is not actually there. Although this can be a powerful method to identify species that are difficult to find, it should be validated using other approaches, like seeing the animal itself.

Additionally, the method is still pretty new and there are some aspects that need to be improved. The environment can affect the detection of the DNA. For example, in a river or lake, flow and sediment in the water can affect the detection result. eDNA detection does not work as a “one method fits all”. Each new application of the method has to be customized for the type of animal and environment.

Flowing water can dilute the eDNA concentration or bring it downstream. Image credit: Finetooth

All in all, this new method provides us with new ways to non-invasively gather information about biodiversity. Combining traditional methods and eDNA detection gives us the most powerful insight into biodiversity that we have ever had.

Damned Rivers: The Story of Pristine Rivers About to be Shackled for Energy

If you live in Europe, it’s hard to find a river that has not been polluted or dammed yet. However, a riverine treasure trove still exists: the Balkan Peninsula has many pristine free-flowing rivers well known to lovers of pure nature and adrenaline.

Unfortunately, this is about to change.

Currently, 2,683 hydropower plants are planned in this area stretching from Slovenia to the north of Greece. This is a massive increase from the current 714 plants in operation. Serbia and Greece have the highest number planned. Nearly every major river is targeted; even rivers that run through natural reserves are not safe. For example, the Mavrovo National Park in FYR Macedonia has a total of 2 large and 15 small hydro plants planned for it.


This is Europe’s last large wild river and it’s about to get dammed. Image credits: Krzysztof Dudzik.

Why build hydropower plants in the first place?

Hydroelectric plants work by damming the river so that the water’s level on that side of the dam is higher than the water on the other side. As it flows from the higher side to the lower side, the water drives a turbine to generate energy. The amount of energy produced by the dam depends on how far the water drops, the flow of the river, and the efficiency with which the energy is converted.


The inner workings of a hydropower plant. Image credits: Tennessee Valley Authority

Hydroelectricity is the most widely implemented energy source that provides fossil-fuel-free energy (though their carbon neutrality is under debate). It is considered a safe and reliable energy source. Many countries are divesting from fossil fuels in an effort to slow down climate change and they need to implement alternative energy sources. For instance, Macedonia is part of the “Regions 202020 Network” and has agreed to increase renewable energy by 20% and decrease greenhouse gas emissions by 20% by the year 2020. It is mainly switching to hydropower to do so.

Negative Consequences

There is also a darker side to this energy source that is usually misinterpreted as “green and renewable”. Currently, about 80% of the rivers in the Balkans are in good ecological condition. However, hydropower plants completely alter river habitats because they dam the river. Turning a flowing river into pools of standing water, similar to lakes, contributes to eutrophication and increases toxicity of the water.


Hydroelectric dams turn rivers into lakes. Image credits: U.S. Bureau of Reclamation

Consequently, this process has a large effect on wildlife in and around the river. Migrating fish have trouble crossing the dam and fish that enter the turbines can be harmed. These rivers are the home of the endangered Huchen fish, a salmon, that migrates to reproduce and would be severely affected by the proposed dams. The hydropower plants would exterminate many species including birds, other fish, and invertebrates that depend on fast flowing, oxygenated water for their survival.

This Balkan Lynx is one of the many species that will be affected the future dams. Image credits: Bernard Landgraf

That’s not all that will be destroyed. Roads and pipelines built for hydro power plants damage habitat on land. This is critical for a chain of species such as the Balkan lynx, endemic butterfly species, and other organisms that spend their lives between river and land. For instance, the rare butterfly Brown’s Grayling, which was sold for 1000 € a specimen, is threatened by a series of hydropower plants being built over a large part of its habitat. Ecologists are worried that the dams will destroy these unique habitats irreversibly. These rivers are very poorly studied so even the wealth of what could be lost is not completely known.

Additionally, hydropower plants divert the water and change the surrounding area, making the area useless for farming, cattle grazing, and tourist activities. With the decrease in aesthetic value, tourism will be negatively impacted in an already poor region.

What can be done?

Part of the rush to build these hydropower plants is to have them finished before the Balkan countries obtain EU membership and have to comply with stricter guidelines. A master plan including local governments, the EU, and investors should be created to minimize the damage to these rivers.

In addition, the approved power plants should go through rigorous environmental assessments, and if possible, built to reduce the impact on the environment. The environmental assessments that have been conducted so far have been questionable, not the least because so little is known about these rivers.

These are the last pristine aquatic habitats in Europe and should be protected before they disappear. In looking for solutions to climate change we should make sure that our Balkan pearls are not lost in the process.

There is a campaign to stop this excessive damming called “Save the Blue Heart of Europe”. Their website has more information about the unique habitats under threat and the actions being taken to protect them.

Why do onions make you cry?

Onions are one of the few truly global foods, with every major cuisine using the onion as a key ingredient. This means that millions of people are reduced to tears when preparing this hardy vegetable, but why? There’s some chemistry behind this delicious vegetable and why it makes you cry.

The culprit. Image credits: Colin

Sulfuric acid in your eyes

When onions grow, they absorb sulfur from the soil to form amino acid sulfoxides. When you cut into an onion, you slice open the onion’s cells causing their insides to pour out, along with all these substances. These sulfoxides then react with enzymes to form sulfenic acid. It is quite unstable and rearranges to form syn-propanethiol S-oxide, a combination of sulfuric acid, sulfur dioxide and hydrogen sulfide. A lot of un-unpleasant substances!

This gas drifts up to the eyes of the cutter and makes contact with nerve-endings on the surface of the eye. Nerves recognize it as dangerous and interpret the contact as a burning sensation, so the tear response reflexively makes tears to combat the irritation.


The contents of these onion cells are what makes you cry. The amino acid sulfoxides responsible for making you cry are absorbed from the earth when the onion grow. Interestingly, it is the same substance that gives the onion its taste. Image credits: Umberto Salvagnin

Cooked onions don’t hurt

Cooking the onion inactivates the enzymes so that it doesn’t irritate your eyes while you are cooking or enjoying your meal. The sooner you cook it, the sooner it stops hurting.

The cooking part isn’t so bad. Image credits: DocteurCosmos

What can you do?

No one likes crying, and if you do have some reason to cry, it definitely shouldn’t be onions. There are many different strategies to try if you are tired of weeping every time you are trying to make French onion soup. They all revolve around keeping the sulfuric gas from reaching your eyes.

  • Block the gas completely. You can wear regular or fancy safety goggles, but make sure that they are sealed at the sides.
  • Slow down or inhibit the reactions that create the irritating compound. Freezing the onion for 15 minutes or keeping it in the refrigerator results in a sting-free cutting experience.
  • Re-direct the irritating gases. Cutting under running water works though it is rather logistically difficult. A more practical method is to turn on the kitchen stove vent and cut under it.
  • Draw out the sulfuric compounds from the onion. Soaking the onions in water for 15 minutes works but causes the onions to lose some flavour.
  • Buy different onions. Sweet onions, scallions, and red onions cause less irritation while white onions are the worst at making you cry because they absorb more sulfur from the soil.

Other old wives’ tales that that do not hold up in practice are lighting a candle and chewing gum while cutting.

So, there you have it – why onions make you cry, according to science, and how you can stop it. Bon appétit!

Why do men even have nipples?

If you feel silly for wondering why men have nipples you can feel a bit better knowing that Darwin asked himself the same question. What is the point of having nipples if men can’t breastfeed?

Darwin’s idea was that both men and women used to be able to breastfeed their children. Then men who breastfed passed some disadvantage on to their offspring, such as being able to raise fewer of them than women, and the ability was inactivated over time due to disuse. However, the answer to this question actually lies in human development rather than evolution.

Spoiler alert: it all happens when you’re an embryo. Image credits: Anatomist90.

As the embryo starts to grow within the mother’s womb, it is a generic human being. If it continues to grow undisturbed it will be born as a female. At week 4 of development, milk lines develop; they are stripes of tissue that extend from the armpits to the thighs and later regress to form two nipples. Sometimes, extra nipples can be left along this pathway (that’s how Mark Wahlberg got a 3rd nipple).

However, if a Y chromosome is present, the embryo will sexually differentiate to become male by producing factors which block the development of female structures. Sexual differences appear in week 7, with the gonads differentiating into a testis or ovary. So nipples are present before the sex of an embryo is fixed.

A man with extra nipples. Image credits: Thomas Godard.

Nipples in men do not pose a disadvantage so they are not evolutionarily selected against, as Darwin thought, so men continue to have nipples. It is difficult to lose an organ if it is not harmful, even if it is no longer useful. For example, humans still have tailbones and appendixes although neither is useful anymore.

Men having nipples may cause you to wonder:

Can men breastfeed?

If you’ve tried this at home, you’ll know that the answer is no. However, there is a rare condition called galactorrhea where affected men can lactate. This condition is often brought on by a testosterone deficiency or imbalance. Alcoholism, severe starvation, or other liver stress can cause male lactation because the liver usually controls the release of prolactin, which is a hormone that regulates milk production.

Can men get breast cancer?

It is rare but some men do get breast cancer. Only about 0.001% of men get it. Men have a small amount of breast tissue, an amount that is similar to a girl before puberty and is still vulnerable to cancer-causing mutations.

Do other male mammals have nipples?

Most other mammals have nipples; the word mammal even comes from the Latin “mamma” which means teat. However, there are exceptions. Monotreme (egg-laying mammals) males, such as platypuses, do not have nipples but then again neither do the females; they excrete milk through modified sweat glands. Other exceptions are male horses and some male rodents, which do not have nipples either.

On the other end of the spectrum, two species of bats, dayak fruit bats and masked flying foxes, have milk-producing males — although it is not known what role, if any, that they have feeding offspring. Some male goats have also been found to produce milk. Theoretically, lactating males should evolve in animals with one monogamous partner, unreliable food sources, and when both parents care for the offspring.