Today’s sloths are small and slow-moving. They are vegetarians and feed mainly on leaves and fruit, although some species have been known to eat bird eggs as infrequently as they can. But their ancient ancestors were real giants – giant ground sloths and according to a new study, scientists have proven that they are omnivores and are very active carnivores.
Lead author of the study Julia Tejada, a research associate at the American Museum of Natural History and a postdoctoral researcher at the University of Montpellier, said: “Are they scavengers? or those who specialize in stealing the prey of other predators, before we can say for sure, more detailed and in-depth studies are still needed.”
“But now we have strong evidence against the long-held hypothesis that the giant ground sloth is a vegan animal.”
To determine what ancient terrestrial sloths ate, the researchers analyzed the amount of nitrogen isotopes found in their fur. They looked for an isotope called nitrogen-15, which indicates an animal’s position in the food chain – the more this isotope is present, the more meat it eats.
Although the researchers found that some giant ground sloths, such as Nothrotheriops shastensis of North America, were actually herbivores, they also discovered that several other giant ground sloths were carnivores. complex. One species of ground sloth found in Patagonia, Mylodon darwinii (M. darwinii), also known as Darwin’s ground sloth, has enough nitrogen-15 in its plumage to indicate that it eats both plants and meat.
This giant ground sloth was discovered by Charles Darwin in 1832 and it was later named after him – they are animals that weigh 2,200 to 4,400 pounds (1 to 2 tons) and can grow up to 13 feet (4 feet) long. meters). It lived in South America from 1.8 million to 10,000 years ago during the Pleistocene epoch.
“The results of the study clearly indicate that Mylodon is not a vegan, but is instead an omnivore,” explained Tejada and her co-authors in a published study. in Scientific Reports.
The team suspects that M. darwinii is more of a scavenger than a predator. The lack of bones in the sloth’s feces suggests that it either scavenged the carcass of other animals that were killed or may have obtained animal protein from eating eggs.
While the new findings are surprising, they also answer some longstanding questions about how these ancient giant ground sloths survived.
For example, M. darwinii has small teeth – the teeth and stomach seem too small for a thriving herbivore. This would seem to pose problems for vegans, but it is advantageous for omnivores, allowing them to easily digest high-energy foods. like meat.
Furthermore, scientists have long suspected that there simply wasn’t enough vegetation for all the herbivores that lived in South America at the same time as the giant ground sloth.
Therefore, sloths can eat both meat and plants. Indeed, its varied diet has helped the animal survive despite scarce resources. The researchers also suggest that it may have begun to adapt to eating meat to survive in resource depletion.
“These results provide the first direct evidence of omnivores in ancient sloths, and, accordingly, the need to reassess the entire ecological structure of ancient mammal communities. of South America,” said Tejada, “because the giant ground sloth represented a major component of these ecosystems over the past few million years”.
The researchers hope to learn more about their feeding habits and shed light on how giant sloths once lived. Certainly, there is much more to learn about these mysterious giants.