Tag Archives: killer whale

Killer whale grandmothers boost survival of young, may explain menopause

Unlike the vast majority of mammals, human females can live decades after they are no longer able to conceive. In fact, scientists know of only four other animals besides humans that go through menopause, and they all live underwater (killer whales, short-finned pilot whales, belugas, and narwhals). A new study of killer whale grandmothers may help unravel the evolutionary threads that could explain menopause.

A 72-year-old orca female breaching the water. She hasn’t been able to conceive for some decades, but her leadership can dramatically improve a pod’s survivability. Credit: Kenneth Balcomb, Center for Whale Research.

Killer whales, also known as orcas, live in matriarchal pods in which both males and females stay with their mothers for life. Males typically don’t survive past age 30. Meanwhile, females will start reproducing at 15 and stop having babies in their 30s and 40s, experiencing menopause just like humans do. And, like humans, orca females can live for decades following their menopause.

According to one hypothesis, menopause evolved because it frees up resources in a tight-knit group and grandmothers have more incentive to look after grandchildren when they have young of their own to rear. In orcas, at least, there are some clear advantages, particularly considering their matriarchal social hierarchy.

Previous studies have shown that post-reproductive female orcas provide an important leadership role when foraging for food. In a new study, researchers at the University of York adds weighed to the important role of grandmother orcas, finding that they considerably raise the survival rates of pod calves.

The research team, led by Dan Franks, a biologist at the University of York, analyzed behavioral and demographic data spanning 36 years on two populations of killer whales. The populations included several pods, made up of different family groups, that foraged off the North West Pacific Coast of Canada and the United States.

Pods where there were more grandmothers who were no longer able to reproduce improved the survival chances of their grand-offspring, the data showed. Their positive impact was the most significant in times of food scarcity — pods that lost post-menopausal grandmothers lost more calves when there was less salmon to catch.

“The death of a post-menopausal grandmother can have important repercussions for her family group, and this could prove to be an important consideration when assessing the future of these populations. As salmon populations continue to decline, grandmothers are likely to become even more important in these killer whale populations,” Franks said.

The researchers believe that the evolution of menopause has increased a grandmother’s ability to take care of grand-offspring because they are free to focus time and resources on the new generation. The same evolutionary pressure may explain why humans go through menopause as well, according to the study published in the Proceedings of the National Academy of Sciences.

 “The findings help to explain factors that are driving the whales’ survival and reproductive success, which is essential information given that the Southern Resident killer whales – one of the whale populations under study – is listed as endangered and at risk of extinction,” Dr. Stuart Nattrass, from the University of York, added.

“We suspect when breeding grandmothers are supporting their own calves, their movement and activity patterns are constrained and they are not able to provide support and leadership in the same way as post-menopausal females. Also, grandmothers with their own calves will be busy caring for their own calves, and be able to invest less in their grand-offspring, compared to post-menopausal grandmothers.

“We are currently conducting observational studies with drones to directly study helping behaviour between family members in these killer whales.”

There are still many open questions regarding menopause. In the future, studies on narwhals, belugas, and short-finned pilot whales may help provide more insight. What scientists know already is that the ability to live beyond a female’s fertile years evolved three separate times in toothed whales — once for killer whales, once for short-finned pilot whales, and once for the shared ancestor of belugas and narwhals. Perhaps other creatures have different evolutionary motives for developing menopause, but in orcas, at least, it seems to be very important for the species’ survival.

How orcas hunt — and some surprising findings

The orca (also known as the killer whale) is not only an incredibly intelligent and social creature but it’s also difficult to study, and quite possibly endangered — we don’t really know because they’re difficult to study. In order to understand their ways, researchers tracked a group of them for over a decade, developing a new technique to analyze how orcas hunt beneath the waves.

Orcas are sophisticated and highly intelligent hunters — but that hasn’t stopped their numbers from decreasing in many parts of the world. Different groups live in different environments and have different diets, so it’s hard to establish how they are faring as a whole, but we know at least one group wasn’t doing so well.

‘The southern resident killer whale population was listed as endangered in the United States in 2005,’ says Jennifer Tennessen from the National Oceanic and Atmospheric Administration (NOAA).

The reason was likely the decline of Chinook salmon in the Pacific Northwest, which is their main source of food. But in order to confirm this, researchers had to understand just how (and how much fish) these whales hunt.

In order to accomplish this, they attached monitoring tags to 21 whales to record their sounds and underwater movements. The team noted when they rise and descend from the surface, what their preferred routes are, and how they hunt. As if this wasn’t difficult enough, in order to be able to receive the data, Tennessen and colleagues had to follow the orcas in inflatable boats — regardless of the weather.

‘Fieldwork is one of the most exciting yet simultaneously challenging aspects of the research,’ says Tennessen.

It was all worth it in the end, though: once they got to shore, the team downloaded and analyzed the data, looking for patterns between movements and tell-tale echolocation clicks produced whenever whales closed in on a fish.

‘Once a fish has been detected, the killer whale angles its body steeply downward, begins a descent to depths of about 50-300m, and then remains underwater for about 7-10min while pursuing the fish’, says Tennessen, adding that they abruptly roll on their sides and change direction frequently during a pursuit.

They then input these patterns into a computer algorithm, identifying the details of these signature 126 occasions when the killer whales intercepted a tasty fish. There were a few surprises, though.

For starters, the whales did not always appear to be successful. This was surprising because making a decisive move consumes quite a lot of energy, which means that there should be a greater payoff.

Even more surprising was the realization that males hunt more than female — something which is unexpected from a matriarchal species, and has not been observed previously. Researchers suspect that this happens because male spend more energy.

‘[This] suggests that males may need to forage more in order to meet their greater metabolic needs,’ she concludes.

The study was published in the Journal of Experimental Biology.

Credit: Pixabay.

Killer whales display personality traits such as playfulness, cheerfulness and affection — just like humans or chimps

The orca (Orcinus orca), also known as the killer whale, has the second largest brain of all marine mammals. They have their own local dialects, coordinate each other in sophisticated hunting teams, teach one another specialized methods of hunting, and pass on behaviors that can persist for generations. These are really smart creatures, who are also extremely socially savvy. What’s more, according to a new study, orcas display distinct personality traits such as playfulness, cheerfulness, and affection, akin to chimps or even humans.

Credit: Pixabay.

Credit: Pixabay.

Researchers assessed the personalities of 24 captive orcas at  SeaWorld Orlando, SeaWorld San Diego and the Loro Parque zoo in Tenerife, Spain. The animals’ trainers and other staff that worked closely with the killer whales had to complete surveys that ranked each animal on a list of 38 personality traits. The traits were analyzed and then compared with previous studies of the same personality traits for chimpanzees and humans.

“This is the first study to examine the personality traits of killer whales and how they relate to us and other primates,” lead researcher Yulán Úbeda, a doctoral student in psychology at the University of Girona in Spain, said in a statement. “These similar personality traits may have developed because they were necessary to form complex social interactions in tightly knit groups that we see in killer whales, humans, and other primates.”

The psychologists measured personality traits with the ‘Big Five’ model, which describes personality across five dimensions: openness, conscientiousness, extraversion, agreeableness, and neuroticism. This simplified model describes personality traits using a combination of single adjectives and descriptive phrases.

The results suggest that killer whales have personality traits that are similar to both humans and chimpanzees, although they lean more towards chimps. Particularly, killer whales scored on par with chimps and humans for extraversion (e.g, playful, gregarious, sociable). Killer whales and chimps also shared personality traits for conscientiousness (e.g., constant, stubborn and protective) and agreeableness (e.g., patient, peaceable and not bullying).

Killer whales live in tightly knit social groups known as pods. Individuals hunt together, share food, and communicate using sophisticated language.  Remarkably, orcas — which are actually a species of dolphins found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas — can also imitate sounds from bottlenose dolphins, sea lions, and even humans. The fact that orcas have personality is perhaps best illustrated by the heartbreaking case of a 20-year-old killer whale, known as J-35 or Tahlequah, who began pushing her dead newborn calf off the coast of Vancouver Island. The grieving mother kept the calf afloat for 17 days while swimming hundreds of miles. Other members of the pods helped the mother, even though this had hurt the pod’s ability to hunt. The behavior was recorded in July and gained international news coverage.

“It is unbelievably sad,” Brad Hanson, a wildlife biologist at the Northwest Fisheries Science Center, told The Seattle Times. “It reflects the very strong bonds these animals have, and as a parent, you can only imagine what kinds of emotional stress these animals must be under, having these events happen.”

Scientists are not sure if killer whales really do feel grief — a complex emotion that’s difficult to gauge, although it may be present in species that live in tight-knit groups, such as chimpanzees, elephants, and giraffes.
“Some previous studies suggest that the mother’s contact with the lifeless body could be important for the mother to make a psychological adjustment to the death of her offspring,” Úbeda said. “In any case, those behaviors show how complex these animals are.”
The current study suggests that the personality traits of killer whales and primates evolved independently of one another, as a byproduct of the advanced cognitive abilities required for complex social interaction — essentially convergent evolution in action.
As a caveat, the study, which was published in the Journal of Comparative Psychology, was performed solely on captive orcas, which have altered personalities like increased neuroticism and aggression. To the authors’ merit, it’s incredibly challenging to assess the personality traits of killer whales in the wild. That being said, the findings do not necessarily reflect the personality traits of killer whales found in the wild.

Half of world’s killer whales could disappear in next 30 years due to toxic pollutant

Although highly toxic polychlorinated biphenyls — known as PCBs — have been globally banned in 2001, the long-lived chemical is still taking a huge toll on marine wildlife. According to a recent study, half of the world’s orca populations could collapse in the next 30 to 50 years due to PCB contamination.

Credit: Pixabay.

The killer of killer whales

Orcas (Orcinus orca), also known as killer whales, have the second largest brain of all marine mammals. They have their own local dialects, coordinate each other in sophisticated hunting teams, teach one another specialized methods of hunting, and pass on behaviors that can persist for generations.

Remarkably, orcas — which are actually a species of dolphins found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas — can also imitate sounds from bottlenose dolphins, sea lions, even humans. Take Wikie, for instance, a killer whale which is able to produce human sounds such as ” “hello”, “Amy”, “ah ha”, “one, two” and “bye bye” (audio player below).

But these sensitive and highly intelligent creatures are in great distress. PCBs, organic compounds once used in capacitors, oil paints, and other industrial applications, are altering the orcas’ behavior, affecting their reproduction, and damaging their immune system — so much so that scientists fear many pods around the world will collapse because of it.

The manufacturing of PCBs was banned in the United States and other countries during the 1970s and 1980s after studies showed how dangerous they can be. In 2001, a worldwide PCBs ban was adopted at Stockholm. However, the chemicals still persist in the water and the food chain, jumping from the zooplankton to fish and seals, which are the orca’s favorite meals. With each jump up the food chain, the concentration of the toxic compound increases. Being at the top of the food chain, orcas have built up high concentrations of the carcinogens in their blubber.

According to a recent paper published in the journal Science, some orcas carry as much as 25 times the amount of PCBs known to alter fertility. Killer whales are particularly threatened in heavily contaminated areas like the waters near Brazil, the Strait of Gibraltar and around the UK. In waters around the British Isles, researchers estimate, only 10 killer whales remain. 

“This suggests that the efforts have not been effective enough to avoid the accumulation of PCBs in high trophic level species that live as long as the killer whale does. There is therefore an urgent need for further initiatives than those under the Stockholm Convention,” Dr. Paul Jepson from the Zoological Society of London’s Institute of Zoology said in a statement.

Not only are PCBs slow to decay in the environment, but they’re also passed down directly from mother orca to offspring through fat-rich milk. This means that the toxic chemicals remain in the animals’ body instead of being released into the environment. An orca can live as long as a human, which means that many individuals were still alive during PCB’s heyday, before the worldwide ban. Populations that look healthy today may still be at great risk, the researchers say.

“We know that PCBs deform the reproductive organs of animals such as polar bears. It was therefore only natural to examine the impact of PCBs on the scarce populations of killer whales around the world,” said Professor Rune Dietz from the Department of Bioscience and Arctic Research Centre, Aarhus University, who initiated the killer whale studies and is co-author of the article.

The researchers reviewed data from existing literature, along with their own records, which included information on PCB level in more than 350 individuals — that’s the largest number of killer whales ever studied. The data was fed into a model that predicted the effects of PCB on the mortality and number of offspring of killer whales over a period spanning a century. The results suggest that 10 of the 19 populations the authors studied were already in decline.

“The findings are surprising. We see that over half of the studied killer whales populations around the globe are severely affected by PCBs” postdoc Jean-Pierre Desforges from Aarhus University, who led the investigations, said in a statement.

Banning PCBs clearly made things better for orcas, but the study’s findings suggest we need to do more in order to improve their outlook. PCBs are still present in legacy products, such as transformers or cable insulation, and these need to be carefully tracked and safely disposed of. Meanwhile, other threats to orcas such as noise pollution, climate change, and food scarcity need to be addressed in order to help populations recover.

Grieving orca carries dead calf for seven days in heartbreaking ritual

The calf only lived for half an hour, but its heartbroken mother still refuses to let go. In one of the most stunning mourning rituals ever observed in the animal world, the mother carried its calf’s body around for seven consecutive days.

J35 and her calf. Photo by Dave Ellifrit, Center for Whale Research.

She carries it ever so gently, either by the fin or on her head, not to make any dent in the tiny, lifeless body.

The orca goes by the rather unceremonious name J35 — but Jenny Atkinson, executive director of the Whale Museum on Washington’s San Juan Island, prefers to call her differently: Tahlequah, a moniker given her in the museum’s adopt a whale program.

Tahlequah is part of a population native to the coast of Victoria, British Columbia, called the Southern Resident killer whales (orcas are also called killer whales). The Southern Resident group has been suffering from environmental degradation and a dwindling food supply. Biologists also fear they are undergoing a genetic bottleneck, which can be extremely problematic for the group.

Like all orcas, Tahlequah and her family are constantly on the move, and typically bring joy to people watching them from shore. But her current journey, which has taken her some 150 miles around the San Juan Islands and Vancouver, has become a desolating spectacle — an almost perfect metaphor for the killer whales’ plight.

Tahlequah refuses to let go of her calf’s body, carrying with her everywhere she goes. Sometimes she carries it on her head, and sometimes she gently bites its flipper to bring it back up after it sinks. She brings it back to the surface every time, says Balcomb.

“We know it happens, but this one is kind of on tour almost, like she’s just not letting go,”  said Ken Balcomb, founder chief scientist for the San Juan Island-based Center for Whale Research,. “It’s a very tragic tour of grief,” he added.

Grief

It’s not unheard of for an orca to carry a dead calf around for hours. Smart and sociable, orcas have impressive cognitive abilities. They are socially aware and are able to form different types of calls, depending on the nature of the situation. Recent studies have also shown that orcas are able to learn and mimic the sounds of different species, such as dolphins and humans. Orca families also have their own culture, which drives genetic evolution. Grief is also a component of this culture — whales mourn their dead, just like we do. Typically, it lasts for a few hours, sometimes up to a day. Balcomb recalls a report from the 1960s that described a similar ritual that lasted for a week — but in all their combined experience stretching out over several decades, Balcomb and colleagues have never seen anything like this.

“It is unbelievably sad,” Brad Hanson, a wildlife biologist at the Northwest Fisheries Science Center, tells The Seattle Times. “It reflects the very strong bonds these animals have, and as a parent, you can only imagine what kinds of emotional stress these animals must be under, having these events happen.”

There’s nothing noticeably different about Tahlequah. She’s a normal, joyous whale, says Atkinson. She’s 20 years old, has an 8-year-old son, and had another pregnancy a few years ago that she didn’t bring to term.
“She has one successful calf, she may have had a miscarriage and now we have a third one that she met,” Atkinson adds. “And I can only imagine, once that baby took breath and swam by mom, that the bond they would have already hared had to have deepened. So maybe that makes this even more painful.”
The behavior is not without consequence. It’s not clear if Tahquelah is eating or not, but she is showing clear signs of emaciation. Dave Ellifrit of the Center for Whale Research says you can see the hollowed-out shape of her head behind her cranium, indicating that a great amount of fat has already been wasted. Michael Weiss of the University of Essex, working with the Center for Whale Research, also laments how small she has become, and how she moves around with the tiniest of blows. She is also showing signs of exhaustion, and she is not maintaining her connection to the other members of the pod. In a matriarchal society like that of the orcas, which greatly depends on mothers and grandmothers, Tahquelah’s precarious state can also threaten the others — which could be devastating.

A fading population

The threats to the local orca pods are grave and many, and the situation is unlikely to improve if things continue as planned.

“Southern Resident killer whales are gravely endangered, and they desperately need our help,” the Center for Whale Research homepage urges.

Balcomb and colleagues started monitoring the area’s orca population in 1976. At the time, it numbered 70 whales — after 50 individuals had been taken to become attractions in marine parks. After federal protection measures were introduced, the number peaked at around 100 and then started to decline again. Today, there are 75 individuals in the area — but that’s not the most pressing problem.

Given these numbers, there should be about nine babies being born each year, to maintain the population. Instead, no calves have been born in the past three years. Functionally, the group is almost extinct, and things may yet be even worse.

Biologists have said that the whale population is decreasing due to noise pollution from ship traffic, as well as waste being thrown into the water. A recent measure would expand the Trans Mountain Pipeline, which carries crude and refined oil from Alberta to the west coast of British Columbia. This would further increase tanker traffic through the orcas’ habitat, exposing them to more noise, disruption, and potential spills.

But the biggest problem of the orcas is the food — or rather, the lack of it. Nearby populations (such as the Bigg’s killer whales) are doing much better because they eat seals, which are quite abundant. But Southern Resident killer whales feed on Chinook salmon, which are dwindling throughout the area. Listed as an endangered species for more than a decade, the orcas depend on a salmon species which is itself endangered, and that does not bode well. It’s not exactly clear why the salmon population is going down, but two common culprits — climate change and overfishing — are likely to blame.

It’s not like things are without hope. In May, Gov. Jay Inslee of Washington signed an executive order to protect Southern Resident orcas, bringing together a group of state, tribal, provincial and federal officials, to help protect the region’s orcas.

“The loss of a newborn orca calf from our endangered southern resident killer whale population underscores what’s at stake as we work to protect these iconic, beautiful animals from vanishing completely,” Mr. Inslee tweeted this week.

Among all this, a grieving mother and her lifeless child, a tragic story and a sign of what’s likely to come. Tahlequah is doing this for her own reasons but maybe, just maybe, she’s also trying to send out a message.

“She’s telling the story far better than I can that these whales are in trouble,” he says.”It’s a message. These are pretty amazing animals. They know they’re being watched, they know what’s going on and they know that there’s not enough food. And maybe they know that we have something to do with it.”

Killer whales shed light on the mystery of menopause

To this day, menopause remains a puzzling concept but researchers may be getting closer to the truth by studying orcas – killer whales.

Killer whales also reach menopause later in their life. Image credits: Robert Pittman / NOAA.

Menopause has only been identified in a handful of species, including humans, killer whales, and chimps. Killer whales start having calves when they’re around 15 and stop when they’re 30 or 40 even though they can live up to 100 years old. Now, a team led by Darren Croft of the University of Exeter published data from a 40-year-old study which offers an intriguing clue as to why the whales stop reproducing later in life.

What they found is that there seems to be some sort of biological contrast between orca generations. When older females reproduce at the same time as their daughters, the calves of the older generation have are twice as likely to not reach the age of 15. But when older whales had calves in the absence of a reproducing daughter, their offspring did just fine. Researchers believe this happens because of competition.

“It’s not that older mothers are bad mothers, that they’re not able to raise their calves as younger mothers,” says Croft. “It’s that when they enter into this competition with their daughters, they lose out and their calves are more likely to die.”

The competition, as it so often happens in nature, is centered around food. Older females are more likely to share their food with others because they feel a stronger sense of kinship to the group, while younger females feel more detached (they haven’t yet formed such a strong social bond). In fact, older females are key to the survival of others, while young mothers focus only on their calves.

“It’s not that older mothers are bad mothers, that they’re not able to raise their calves as younger mothers,” says Croft. “It’s that when they enter into this competition with their daughters, they lose out and their calves are more likely to die.”

The idea that menopause emerges as a genetic safeguard to the legacy of the family is not new and has been proposed in the case of humans as well – but in a different form. In many human cultures (both ancient and modern), grandmothers take extra care of their grandchildren. If they would have children of their own, then they wouldn’t place such an emphasis on their grandchildren and in time, the family is better off without the grandmother’s kids – this is called the Grandmother Theory. However, these new findings somewhat contradict the Grandmother Theory and come up with a different reason for menopause.

Anthropologist Kristen Hawkes, at the University of Utah doubts that this study tells the full story. She believes killer whales are very difficult to study and they’re doing all sorts of stuff we don’t yet understand so any parallel between them and humans is forced.

“They’re doing all kinds of stuff where you can’t see it, and even to get demographic data is just so tricky, because they’re all underwater and they’re long-lived,” she says.

Whatever the truth may be, menopause remains an intriguing mechanism — one for which biologists and anthropologists will doubtlessly argue for years to come.

Journal Reference: Darren P. Croft et al – Reproductive Conflict and the Evolution of Menopause in Killer Whales. DOI: http://dx.doi.org/10.1016/j.cub.2016.12.015

Cooperative prey hunting and sharing observed in Norwegian seal-eating killer whales

Drones have become increasingly used for research on cetaceans. Remotely controlled from distances of up to several hundred meters, drones enable the capture of unbiased behaviors whilst removing potential disturbances that could arise from boats standing directly around the animals. Moreover, drones enable observations of activities that may occur within the first meters below the surface, yet completely out of the observers’ sight.

Image credits: Norwegian Orca Survey

Image credits: Norwegian Orca Survey

In Norway, a research project regularly uses drones to investigate dietary habits and predation behaviours of killer whale groups. So far, and based on studies from the last three decades, Norwegian killer whales have been thought to be relying on the Atlantic herring as a main prey. However, a subset of groups also appears to regularly prey upon pinnipeds, as first documented by Vongraven & Bisther (2014). Part of an ongoing study that aims at monitoring the extent of killer whale predation on pinnipeds in northern Norway, a research team recently launched a drone above a group of killer whales hunting and feeding on a harbour seal. The drone captured stunning footages showing a group of killer whales cooperatively hunting and subsequently sharing a pinniped-prey. The video is available below.

https://www.youtube.com/watch?v=qN45uAJ1Aqw

With consistent heading, speed and between-individual spacing, the five killer whales, presumed to be foraging, were travelling with approximately 5 knots along the shoreline. Suddenly, the large male of the group showed drastic behavioral changes, displaying sharp turns, explosive breathings and arching his back while diving. In a matter of only a few seconds, all the four other whales adopted similar displays. Thereby, the perfectly synchronous surfacing behaviour that first characterized the travelling whales rapidly turned into a pattern where the whales were alternately coming up to breath. Each whale surfacing seemed to systematically dive straight downwards, and the whole group remained on this restricted spot, where something was apparently going on.

Explanations came shortly when the drone flying above the spot revealed a seal laying on the surface, apparently exhausted. The five killer whales were persistently circling it, leaving it with no chance to escape towards the haul-outs nearby. After a minute, the seal attempted a fast escape down to the bottom, as visible on the footage. The immediate reaction of the five whales, prompted by a flying start, was to rush after it. For a few minutes, the sea surface remained quiet. The seal may have escaped to the bottom where cavities and rocks offer hiding places. Yet, killer whales are skilled top-predators able to cooperatively search and handle all prey types and, eventually, the group came up back to the surface with the prey: dead.

Seal-eating killer whales that frequent Norwegian coastal waters appear to have different strategies to killing their seal-prey, based on the situation. As such, hitting a tired seal laying on the surface with a powerful tail-slap will stun or cause traumas that will weaken the prey, ensuring low risks of injury for the hunting killer whales. The killing method for a seal-prey hiding near the bottom remains uncertain. However, it is likely that the whales would wait for it to drown. Indeed, as shown on the footage, the whales appear to take turns to come up to breathe, ensuring that there are always predators down watching the prey, still holding its breath.

Upon return to the surface, interestingly, the oldest female of the group could be seen leading the carcass towards the surface and taking the first bites out. She then deliberately dropped the carcass, leaving an opportunity for the rest of the group to join the feast. On the footage, the five whales could be seen taking turns to feed on the carcass. After less than 15 minutes, the meal was over and the whales resumed their foraging behavior.

Food-sharing has been previously highlighted in other killer whale populations. As killer whales live in stable groups of related individuals, the benefits of cooperative foraging and prey-sharing are thought to result in increased fecundity and survival of the whole group, thus promoting kin perpetuation.

Drone footages obtained on this specific encounter enabled confirmation of effective predation and subsequent feeding, both of which are extremely valuable for ongoing studies. Great images once more support the killer whale as the ocean’s apex-predator.

This article is by Eve Jourdain and Richard Karoliussen from the Norwegian Orca Survey

Killer Whales Orcas

Culture drives distinct genetic evolution in killer whales — the first non-human animal to do so

Researchers at University of Bern, Switzerland, found that Orcinus orca (killer whales) populations have evolved distinct genetic lineages due to unique hunting strategies. Adults pass down knowledge about what and how to hunt to the young, a form of cultural transfer. This implies that culture has had such a profound effect on the orcas that individual groups have started to diverge. This has only been observed in humans before.

Killer Whales Orcas

Credit: Pixabay

Humans are a globally dispersed species, but the populations vary in their genetic makeup. Environmental cues like temperature, food availability, the seasons and such force adaptations like dark skin in Africa, for instance. But besides the natural ecosystem, humans also receive inputs from their own fabricated microcosmos. We wear clothes, live in homes that shelter us from the elements and farm food.

These cultural cues will also trigger genetic changes, which will vary from population to population. Perhaps the clearest example is the domestication of cattle which forced the adaptation of lactose tolerance genes. Lactose tolerance varies greatly by geographical distribution, though. Up to 90 percent of Northern European populations are lactose tolerant, but in some Asian countries, 90 percent of the population is lactose intolerant.

Lactose Tolerance map

Credit; Nature

Like humans, orcas are also highly dispersed around the globe, living in waters ranging from the tropics to the poles. Like humans, orcas form communities which occupy a certain single area for a very long time, like a permanent settlement. In these communities, the orcas will develop their own hunting strategies, adapting to the kind of prey available. Some will target fish, while other groups or pods will specialize on seals.

These very niched strategies are sophisticated and require the kind of coordination and knowledge which isn’t available from birth. Instead, the adults will train the juveniles over decades if necessary.

Knowing this, some biologists wondered: will these distinct cultural trends result in distinct genetic populations in orcas just like in humans? Andrew Foote at the University of Bern and colleagues set out to answer this question. The team sampled and sequenced genetic material from 50 killer whales belonging to five distinct niches.

Results suggest the five cultural niches corresponded to exactly five distinct genomes, confirming the hypothesis. All of these groups share a common ancestor which lived as recently as 200,000 years ago, the researchers wrote in Nature Communications. 

Foote says each niche was occupied initially by a small group of founding members then gradually expanded. These founding members, which we can call eccentrics because they decided to venture into a new niche, were successful thanks to their individual flexibility. But the survival of the entire pod over centuries in the same niche relies on know-how transfer, hence culture.

This research is striking because it proves culture is powerful enough to transform the genetic makeup of populations, in humans and non-human animals alike. Is this the case of other animals besides humans and orcas? Should be, but there aren’t that many that can boast the necessary characteristics like sophisticated social structure, longevity and high-order intelligence. Whales and other primates might also confirm the findings.

Killer whales are so smart they can learn to speak “dolphin”

Killer whales are smart, we already know that; they’re also really scary. But a new study has shown that they are actually scary smart – up to the point where they can learn the language of another species.

Killer Smart

Image via Animal National.

Killer whales are actually a species of dolphins found in all oceans, from the frigid Arctic and Antarctic regions to tropical seas. They have extremely diverse diets and can adapt to what the local environment can provide. Killer whales are notable for their complex societies. Only elephants and higher primates, such as humans, live in comparably complex social structures. Due to the fact that they have complex social bonds, many scientists have argued that it is not humane to keep orcas (as they are also called) in captivity.

Killer whales have the second-heaviest brains among marine mammals, after Sperm whales. They are known to teach their offspring and to imitate other creatures. They also have advanced communication skills. The killer whale’s use of dialects and the passing of other learned behaviours from generation to generation have been described as a form of animal culture.

“The complex and stable vocal and behavioural cultures of sympatric groups of killer whales (Orcinus orca) appear to have no parallel outside humans and represent an independent evolution of cultural faculties” – a 2001 Cambridge study concluded.

Talk like a Dolphin

Image source.

In this new study, orcas who were familiar with bottlenose dolphins started making similar sounds to the dolphins, with more clicks and fewer longer calls; basically, they started to mimic the bottlenose dolphin language. This could indicate that orcas have their own language and dialects, University of San Diego graduate student Whitney Musser and Hubbs-SeaWorld Research Institute senior research scientist Dr. Ann Bowles published in The Journal of the Acoustical Society of America suggest. More proof is needed however.

“There’s been an idea for a long time that killer whales learn their dialect, but it isn’t enough to say they all have different dialects so therefore they learn. There needs to be some experimental proof so you can say how well they learn and what context promotes learning,” Bowles said.

Considering orcas have different dialects and even express different cultural behavior from one population to another, it seems entirely reasonable (and remarkable) that they are able to learn the language of another cetacean. The fact that they have similar vocal chords also helps in this aspect. However, the fact that they are larger makes it more difficult for them to vocalize.

But why do they do this? It’s still not clear. Researchers are currently more interested in to the how of the story:

“It’s important to understand how they acquire [their vocalization patterns], and lifelong, to what degree they can change it, because there are a number of different populations on the decline right now,” Bowles said. “And where killer whales go, we can expect other small whale species to go — it’s a broader question.”

The Killer whales of Eden, Australia

This story has nothing to do with the study I described above, but I think it paints a good picture on how adaptable orcas really are. The killer whales of Eden, Australia were a group of killer whales known for their co-operation with human hunters of other whale species. Basically, for one orca generation (about 90 years, from 1840 and 1930) they were seen near the port of Eden in southeastern Australia.

The killer whales would find target whales, shepherd them into Twofold Bay, and then alert the whalers to their presence and often help to kill the whales. The whalers would come in, kill the whales, and then allow the orcas to feed off the whales before the whalers brought the whales in. The leader of the orca group was called Old Tom; he would alert the human whalers to the presence of a baleen whale in the bay by breaching or tailslapping at the mouth of the Kiah River.

The unique behaviour of killer whales in the area was recorded in the 1840s by whaling overseer Sir Oswald Brierly in his extensive diaries. It was discussed in many scientific circles and described in many scientific studies. While co-operative hunting between humans and wild cetaceans exists in other parts of the world, the relationship between whalers and killer whales in Eden appears to be unique. What’s interesting is that the initiative for this cooperation came from the orcas – not from humans. It’s not clear how they came up with this idea or how they developed this behavior, but it highlights once again that killer whales are able to develop long-standing relationships with other species – even some as different as humans.

Documents reveal that SeaWorld gives its orcas antidepressants and psychoactive drugs

As if SeaWorld didn’t have enough press with the shocking Blackfish documentary, a document released by Buzzfeed reveals that the marine park gives its whales psychoactive drugs and anti-depressants. According to the Ontario Superior Court of Justice affidavit, SeaWorld’s whale trainers give the animals benzodiazepine, which has a valium-like effect on the mammals.

The document originated from a legal dispute between SeaWorld and rival company Marineland over the transport of a prized killer whale. In the statement it is said that benzodiazepine is similar in effect to Valium and Xanax – something which was linked to mental issues for the orcas. This was also documented in Blackfish. But how dangerous is this substance really?

Jared Goodman, Director of Animal Law at PETA said the document would be detrimental to SeaWorld.

“The veterinary records show that orcas at SeaWorld are given psychotropic drugs to stop them from acting aggressively towards each other in the stressful, frustrating conditions in which they’re confined instead of funding the development of coastal sanctuaries – the only humane solution,” Goodman said.

However, SeaWorld spokesperson Fred Jacobson defended the practice, claiming:

“Benzodiazepines are sometimes used in veterinary medicine for the care and treatment of animals, both domestic and in a zoological setting. These medications can be used for sedation for medical procedures, premedication prior to general anesthesia, and for the control of seizures. The use of benzodiazepines is regulated, and these medications are only prescribed to animals by a veterinarian. Their use for cetacean healthcare, including killer whales, is limited, infrequent, and only as clinically indicated based on the assessment of the attending veterinarian. There is no higher priority for SeaWorld than the health and well-being of the animals in its care.”

It’s important to try to remain objective here – we shouldn’t raise our pitchforks and go against SeaWorld… or at least we should wait before doing that. I for one, dislike this concept, which is basically an aquatic circus; you have marine animals which you are basically training to do tricks for human amusement – nothing more, nothing less. It’s pretty safe to say that these animals are not happy with this type of life, and if you add in antidepressants, you get a pretty grim picture.

Blackfish is a 2013 documentary directed by Gabriela Cowperthwaite – it focuses on the captivity of Tilikum, a killer whale involved in the deaths of three individuals, and the consequences of keeping killer whales in captivity. The coverage of Tilikum includes his capture in 1983 off the coast of Iceland, purported harassment by fellow captive whales at Sealand of the Pacific, incidents that Cowperthwaite argues contributed to the whale’s aggression. The documentary received rave reviews, and for good reason – it is an aggressive, impassioned documentary that will change the way you look at performance killer whales.