Mass Grave of Elephant-Sized Sloths Poses Murky Mystery

By Jeanne Timmons on 04 May 2020 at 2:00AM

Death might have taken weeks; it might have been days. But when it struck, it struck ruthlessly.

Some 20,000 years later, the fossils of these enormous creatures would be found by chance. Many of the bones were disarticulated and had the type of gouges palaeontologists would interpret as traces of trampling by other creatures after they had died. Something catastrophic caused 22 giant ground sloths – many the size of modern elephants – to perish at the same time and in the same place. In a paper published last month, researchers describe what they think led to the sloths’ demise.

The remains of these giant ground sloths – as well as those of an ancient horse, deer, pampathere, and gomphothere – were found in the Santa Elena Peninsula in Ecuador. Fifteen of the giant ground sloths were adults; the rest were subadults and juveniles, a couple of them so tiny that they might have been newborns or even fetuses.

Humans have a long history of exploring and exploiting natural tar seeps in the Santa Elena Peninsula, and these are hardly the first fossils to be found in the asphaltic sediments. Tar seeps in the area enabled indigenous people to seal their boats; in recent history, oil could be found so close to the surface that people could dig by hand to extract it. This much digging into the ground has revealed the numerous fossil treasures preserved within. But, after clearing the edge of a hill, it was a local oil company in 2003 that discovered what would be referred to as “Tanque Loma” – the site of this mass-death assemblage and more. “Loma” means hill, and “tanque” refers to the oil containers that stand atop that hill.

Although the fossils were preserved in asphalt, the authors do not believe this was a true tar pit. When most of us think of Ice Age tar pits, our minds go directly to one of the most famous: the La Brea Tar Pits in California, a site we immediately associate with animals mired in tar with no escape. Yet, even though these giant ground sloth fossils were found in asphalt, the authors find no evidence that they died in it.

More:
https://www.gizmodo.co.uk/2020/05/mass-grave-of-elephant-sized-sloths-poses-murky-mystery/