New study reveals that Mylodon was an omnivore, unlike its strictly plant-eating relatives.
A new study led by researchers at the American Museum of Natural History suggests that Mylodon—a ground sloth that lived in South America until about 10,000 to 12,000 years ago—was not a strict vegetarian like all of its living relatives. Based on a chemical analysis of (fundamental biological compounds that are the building blocks of proteins) preserved in sloth hair, the researchers uncovered evidence that this gigantic extinct sloth was an omnivore, at times eating meat or other animal protein in addition to plant matter. The study, published today (October 7, 2021) in the journal Scientific Reports, contradicts previous assumptions in the field.
“Whether they were sporadic scavengers or opportunistic consumers of animal protein can’t be determined from our research, but we now have strong evidence contradicting the long-standing presumption that all sloths were obligate herbivores,” said lead author Julia Tejada, a Museum research associate and postdoctoral researcher at the University of Montpellier, France. Tejada began the work on this study as a Ph.D. student in the Museum’s Richard Gilder Graduate School collaborative program with .
Even though the six living sloth species all are relatively small plant-eating tree-dwellers restricted to tropical forests of Central and South America, hundreds of fossil sloth species, some as large as an elephant, roamed ancient landscapes from Alaska to the southern tip of South America. Mylodon darwinii, also known as “Darwin’s ground sloth,” is thought to have weighed between 2,200 and 4,400 pounds and was nearly 10 feet long. Based on dental characteristics, jaw biomechanics, preserved excrement from some very recent fossil species, and the fact that all living sloths exclusively eat plants, Mylodon and its extinct relatives have long been presumed to be herbivores as well. But these factors could not directly reveal whether an animal might have ingested food that requires little or no preparation and is completely digested, as happens in carcass scavenging or some other kinds of meat-eating.
To get a more complete picture, the new study uses an innovative approach based on nitrogen isotopes locked into specific amino acids within animal body parts, known as “amino compound-specific isotope analysis.” Found in different proportions in the food consumed by an animal, stable nitrogen isotopes are also preserved in their body tissues—including hair and other keratinous tissues like fingernails, as well as in collagen like that found in teeth or bones. By… Brinkwire News Summary.