Elephant Saves Her Baby Against Hyenas

The descendants of Plioviverrops reached their peak 15 million years ago, with more than 30 species having been identified. Unlike most modern hyena species, which are specialised bone-crushers, these dog-like hyenas were nimble-bodied, wolfish animals; one species among them was Ictitherium viverrinum, which was similar to a jackal. The dog-like hyenas were very numerous; in some Miocene fossil sites, the remains of Ictitherium and other dog-like hyenas outnumber those of all other carnivores combined. The decline of the dog-like hyenas began 5-7 million years ago during a period of climate change, which was exacerbated when canids crossed the Bering land bridge to Eurasia. One species, Chasmaporthetes ossifragus, managed to cross the land bridge into North America, being the only hyena to do so. Chasmopothertes managed to survive for some time in North America by deviating from the cursorial and bone-crushing niches monopolised by canids, and developing into a cheetah-like sprinter. Most of the dog-like hyenas had died off by 1.5 million years ago.
• Bone-crushing hyenas
By 10-12 million years ago, the hyena family had split into two distinct groups; that of the dog-like hyenas and the bone-crushing hyenas. The arrival of the ancestral bone-crushing hyenas coincided with the decline of the similarly built but unrelated Percrocutidae family. The bone-crushing hyenas survived the devastating changes in climate and the arrival of canids, which wiped out the dog-like hyenas, though they never crossed into North America, as their niche there had already been taken by the Borophaginae family. By 5 million years ago, the bone-crushing hyenas became the dominant scavengers of Eurasia, primarily feeding on large herbivore carcasses felled by sabre-toothed cats. One genus, Pachycrocuta, was a 200 kg (440 lb) mega-scavenger that could splinter the bones of elephants. With the decline of large herbivores by the late ice age, Pachycrocuta was replaced by the smaller Crocuta.