Tag Archives: holocene

Giant sloth.

Timeline for giant sloth extinction rewritten by new analysis

The giant sloth may have lived in the slow lane, but it went extinct much faster than previously estimated, a new study reports.

Giant Sloth Bones.

Lithic tool associated with giant ground sloth bones.
Image credits Gustavo Politis, Pablo Messineo.

Researchers at the National University of Central Buenos Aires, Olavarría, Stafford Research, and La Brea Tar Pits and Museum, report that the giant sloth went extinct before the Holocene, the current geological period.

Dirty collagen

Prior research had found that the giant sloth disappeared during the Pleistocene, the geological epoch spanning from about 2.5 million to 11 thousand years ago — the last period of repeated glaciations to grip the Earth (right before the Holocene). However, there was also some evidence pointing to the survival of this species in certain pocket areas (of today’s Pampas, Argentina) up to the Holocene.

The present study comes to invalidate that hypothesis: the giant sloths went completely extinct before the onset of the Holocene, it explains. This new paper used a more stringent testing technique to date the remains of giant sloths found at the Campo Laborde dig site in Argentina. The team recovered collagen from the remains — they note that a single bone had recoverable collagen — that they dated using the radiocarbon technique and used to establish the new timeline for the sloths’ extinction.

The study also provides a glimpse into what went wrong with earlier dating attempts: the collagen used in the current study had been heavily contaminated with compounds leaching from the soil around it. Earlier dating efforts had not taken this contamination into account, they explain, which fouled the results. The team used chemical purification techniques to clean up the collagen before running their analysis, and then extracted specific amino acids that could only have come from the sloth itself, the team explains.

Giant sloth.

Giant sloth.
Image credits Eden, Janine and Jim / Flickr

Their analysis shows that the giant sloth went extinct around 10,570 years ago. This would push the timeline of their disappearance out of the Holocene (previous research found that the animals went extinct around 9,730 years ago, which is during the Holocene).

It’s a distinction that might sound pedantic, but it’s actually quite significant. Humans are currently considered the driving force behind the extinction of many ancient megafauna species, including the giant sloth. The new findings don’t exonerate our ancestors, but they do suggest that they were only part of the problem; their hunting of the giant sloths certainly helped, but it likely happened during a time when the species was buckling, likely under environmental strain from changing climate patterns.

The findings also raise the possibility that other species of huge mammals, especially those in South America (but possibly other places around the globe as well) didn’t make it to the Holocene either. If the collagen in the remains those studies were based on is found to be contaminated, the findings could be off the mark by thousands of years.

The paper “A Late Pleistocene giant ground sloth kill and butchering site in the Pampas” has been published in the journal Science Advances.

Incredible cave lions found preserved in Siberian permafrost

Paleontologists have unearthed two spectacular cave lion cubs, preserved by the permafrost in the Sakha Republic, also known as Yakutia.

These cubs suffered a tragic fate, but they will now be admired by the entire world. Picture: Academy of Sciences of Yakutia

The last glacial period, popularly known as the Ice Age, was the most recent glacial period within the Quaternary glaciation occurring from 100,000 to 12,000 years ago. At the end of this ice age, several species couldn’t adapt to the changing conditions and went extinct – the so-called sabre-tooth cat, wooly mammoth and cave bears among them.

Another, perhaps less known species that went extinct at the end of the ice age was the cave lion. Cave lions looked more like today’s tigers, although genetic analysis revealed that they are more related to modern lions than tigers. These active carnivores probably preyed upon the large herbivorous animals of their time, including horses, deer, reindeer, bison and even injured old or young mammoths. Some cave paintings show them hunting together in a pack, and likely took cover in caves – hence the name. Most of their bones were found in caves, and there is a pretty good fossil record of them. However, these are the most well preserved fossils ever found. They may very well be the best preserved fossils in the world.

‘The find is sensational, no doubt,’ said a source close to the discovery. It is known the remains are free of dangerous infections such as anthrax following initial microbiological analysis, but no other significant details or pictures will be released before the official presentation, which will take place sometime in November.

Along with the lions, scientists also found other animals, incredibly well preserved by the permafrost. Pictures: Academy of Sciences of Yakutia, RGO

Like many other animals, they went extinct at the end of the ice age, but their case is a bit more mysterious – they had all the chances to survive the environmental change. They had few, if any predators, they were smaller than herbivores and better prepared for warmer temperatures and were not prone to getting bogged down in swamps, like wooly mammoths or rhinos. These cubs might answer that question.

Paleontologists also made other remarkable findings in the area, which will be presented together at the same presentation in November.

 

Long term climate study suggests record warming is ahead of us

By observing several indicators, a team of researchers from Oregon State University’s College of Earth, Ocean and Atmospheric Sciences concluded that in as few as 87 years from now, temperatures are expected to be bigger than anytime in the existence of the human species.

holocene

Paleoclimatic research is providing a more detailed look on how the planet’s average surface temperature fluctuated over the Holocene – the current geological era we are in that began ~12.000 years ago. This is practically the time in which the human species really evolved as a civilization, making its mark on the planet, abandoning the hunter-gatherer traditions to settle down into an agricultural, settlement focused lifestyle.

They used indirect markers, like pollen and shells from marine organisms to chart long time warming and cooling trends. They concluded that the hottest period was during the start of the Holocene, with temperatures in the past decade going close to those numbers, but not quite reaching them – that however, will soon change.

“By the year 2100, we will be beyond anything human society has ever experienced,” said study leader Shaun Marcott, a postdoctoral researcher at Oregon State University’s College of Earth, Ocean and Atmospheric Sciences.

According to NASA, the average global temperature for 2012 was 14.61 degrees Celsius (58.3 degrees Fahrenheit); even an increase of a single degree can have catastrophic consequences – bare in mind, this is the average temperature for the entire year for the entire globe. Basically, every 1.8-degree Fahrenheit increase brings with it a (roughly) 20 meter increase in sea levels – but that’s really the least of the problems. In the past century, temperatures have risen by 1.3 degrees, and the trend is accelerating

global warming

This research, which was published in Science, was not the first one to reach this kind of conclusion using such proxies, but it is first to pull together so many of them from all over the world, clearly indicating the rate and magnitude of global warming:

 

“We know that there were periods in the past that were warmer than today — for example, the Cretaceous period 100 million years ago,”  said Michael Mann, a physicist and climatologist at Pennsylvania State University. “The real issue is the rate of change, because that’s what challenges our adaptive capacity.”