The odd-toed ungulates radiate
Horses, rhinos and tapirs diversify across the northern continents and dominate large herbivory.
- When
- —
- Duration
- 21 million years
- Known to
- ± 2 million years
- Era
- Eocene, Cenozoic
Perissodactyls bear their weight on a central toe and ferment plant matter in the hindgut, a less efficient system than the ruminant stomach but one that processes bulk faster. Through the Eocene they are the dominant large herbivores of the northern hemisphere, in far greater variety than the seventeen species left today: alongside horses, tapirs and rhinos there are palaeotheres, the huge brontotheres, and the strange clawed chalicotheres. Their long decline begins when ruminants arrive.