Stable Isotopic diets of Pleistocene horses from southern North America and South America: similarities and differences

PEREZ CRESPO, V. A.; ARROYO-CABRALES, J.; PRADO, J. L.; ALBERDI, M. T.

Salt Lake City

Congreso; SVP 76th Annual Meeting; 2016

SVP

Horses were a group of animals that in the past had great diversity of species and naturally lived on most of the planet, with the exception of Antarctica and Australia. This group originated during the Eocene in North America and diversified into several genera and species, moving across the continent into South America during the late Pliocene where it diversified again. Several species within the genus Equus lived in southern North America (USA: California, Arizona, Nevada, Texas and Florida; and México), as well as in South America during the Pleistocene. Carbon isotopic analyses show that horses from southern North America and South America were C3/C4 mixed feeders that fed upon important amounts of C4 plants?more in South American horses. However, some specimens lived on both continents with either C3 or C4 plant exclusive diets. This may suggest that the genus Equus was a generalist in its diet, but during the transition into the Holocene, all of those groups disappeared in the Americas. It is possible that due to climatic change, plants eaten by horses were replaced by other less nutritive ones; however, human hunting should not be ruled out as a contributing factor for their extinction.