Ancient diets, ecology and extinction of horses
55 to 20 million years ago the Equus had different teeth than our modern Equus, their teeth where short-crowned. This indicated that these animals where browsers. Short crowned teeth are more equiped for browsing than grazing. They browsed mainly leafy and soft plants. Due to adaptation the teeth began to change and numerous clades (a group of organisms that consists of a common ancestor) evolved high crown teeth, more adapt to eat grasses.
In this study they investigated if tooth crown height in combination with isotopes and enamel microwear could tell more about the diet of 6 fossils of the late Hemphillian of the Bone Valley in Florida.
The 6 fossils represent 2 different clades of advanced hypsodont horses with similar high crown teeth and body size. Suspected was that all 6 horses would be grazers. However carbon isotopic and microwear data have shown that the horses were not all grazers. One was a browser and two others where mixed (both browsing and grazing).
Before this study, it was assumed that horses from the Bone Valley had a grazing diet. but after this study it is known that some horses also had a browsing diet, even if the where equiped with high crown teeth.
> From: Bruce J. MacFadden et al., American Association for Advancement of science 283 (1999) 824-827. All rights reserved to JSTOR. Click here for the online summary.
