- Sloth that lived about 1.8 million years ago wasn’t a strict vegetarian, study finds
- 10 feet tall Mylodon darwini, known as ‘Darwin’s ground sloth’, probably ate meat
- It was thought that it was a herbivore because most living sloths eat only plants.
- But chemical analysis of amino acids in preserved dull hair revealed differently
One study found that an extinct land sloth that lived in South America until 1.8 million years ago was not a strict vegetarian like most of its living relatives because it probably ate meat.
Researchers said the 10-feet-long giant was an omnivore that sometimes consumed meat as well as plants.
It was long thought that Mylodon darwini, also known as ‘Darwin’s ground sloth’, was a herbivore as most living sloths eat only leaves, fruit, and twigs, although some are occasionally an insect. Or snack on bird eggs.
However, chemical analysis of amino acids conserved in the hairs of ancient sloths revealed evidence of animal proteins, which suggests they may have been scavengers.
“Whether they were sporadic scavengers or opportunistic consumers of animal protein cannot be determined from our research, but we now have strong evidence refuting the long-standing belief that all sloths were herbivores, ” said lead author Julia Tejada, a research associate at the American Museum of Natural History.
Meat-eater: An extinct sloth that lived 1.8 million years ago in South America wasn’t a strict vegetarian like most of its living relatives because it probably ate meat, a study finds
What was the giant ‘Darwin’s land sloth’?
The first specimen of Mylodon darwinii was discovered by Charles Darwin in 1832.
The first specimen of the ancient ground sloth Mylodon darwini was found by Charles Darwin in 1832.
He identified it as belonging to the same family as modern sloths, but British anatomist and paleontologist Sir Richard Owen later described it as a new species, and named it in honor of its discoverer.
Mylodon, or ‘Darwin’s ground sloth’, lived throughout South America – from Bolivia in the north to southern Patagonia – between 1.8 million years and 12,000 years ago.
Unlike some of its relatives, it didn’t dig or climb trees, and it wasn’t a herbivore, according to new research from the American Museum of Natural History.
It is not known what caused its extinction, although climate change has been suggested as a possible cause.
The six living sloth species are relatively small, plant-eating tree-dwellers that live in the tropical forests of Central and South America.
However, hundreds of their extinct cousins, some as large as elephants, roamed the ancient landscape from Alaska to the southern tip of South America.
One of these species, known as Mylodon darwini, is thought to have weighed between 2,200 and 4,400lbs and was about 10 feet long. It lived during the Pleistocene epoch, between 1.8 million years and 12,000 years ago.
Based on previous research looking at tooth features, jaw biomechanics and recently preserved excreta from fossil species, as well as the fact that most modern sloths only eat plants, it was thought that Mylodon darwini was herbivorous. Were.
But these methods could not reveal with certainty whether an animal would have consumed a food that required little or no preparation and was completely digested, as in the cleaning of carcasses or any other type of meat. Happens in eating.
For this reason, this study used an innovative approach involving the incorporation of nitrogen isotopes locked into specific amino acids – biological compounds that are the building blocks of proteins – within animal body parts, known as ‘amino acid compound-specific molecules’. Known as ‘isotope analysis’.
These nitrogen isotopes are found in the food an animal eats and are preserved in the tissues of its body, including hair, nails, teeth or bones.
By first analyzing amino-acid nitrogen values in a wide range of modern herbivores and omnivores to identify what an eating plant, animal, or mixture would look like, the fossils could then be measured to determine the food they ate. .
This gives paleontologists a unique window into the diet of animals, allowing them to determine their ‘trophic level’ – whether they are plant-eating herbivores, mixed-food omnivores, meat-eating carnivores, or specialized marine Be an animal consumer.
Analysis: However, chemical analysis of amino acids conserved in ancient sloth hair (pictured) revealed evidence of animal proteins, suggesting they may have been scavengers
‘Earlier methods relied solely on bulk analyzes of nitrogen and complex formulas, which have many untested or weakly supported assumptions,’ said study co-author John Flynn from the American Museum of Natural History’s Division of Paleontology.
‘Our analytical approach and results suggest that many of the previous conclusions about tropic levels are at best poorly supported, or plainly incorrect and at worst misleading.’
The researchers used samples from seven living and extinct species of sloths and anteaters — which are closely related to sloths — as well as from a wide range of modern omnivores.
While the other extinct sloth in the study, the North American ground sloth Nothrotheriops shastensis, was determined to be a specialized herbivore, the data clearly marked Mylodon as an omnivore.
“We now have strong evidence to refute the long-held belief that all sloths were herbivores,” said lead author Julia Tejada.
Previous research has suggested that the ancient ecosystems of South America were more herbivores than was supported by available plants, indicating that some of those herbivores may have been finding other sources of food.
The evidence from this new study would seem to support that theory.
‘These results, providing the first direct evidence of omnivory in an ancient sloth species, demand re-evaluation…