The Early Miocene (also known as Lower Miocene) is a sub-epoch of the Miocene Epoch made up of two stages: the Aquitanian and Burdigalian stages. The sub-epoch lasted from 23.03 ± 0.05 Ma to 15.97 ± 0.05 Ma (million years ago). It was preceded by the

Oligocene The Oligocene ( ) is a geologic epoch of the Paleogene Period and extends from about 33.9 million to 23 million years before the present ( to ). As with other older geologic periods, the rock beds that define the epoch are well identified but the ...

epoch. As the climate started to get cooler, the landscape started to change. New mammals evolved to replace the extinct animals of the Oligocene epoch. The first members of the

hyena Hyenas, or hyaenas (from Ancient Greek , ), are feliform carnivoran mammals of the family Hyaenidae . With only four extant species (each in its own genus), it is the fifth-smallest family in the Carnivora and one of the smallest in the clas ...

and weasel family started to evolve to replace the extinct '' Hyaenodon'', entelodonts and

bear-dogs Amphicyonidae is an extinct family of terrestrial carnivorans belonging to the suborder Caniformia. They first appeared in North America in the middle Eocene (around 45 mya), spread to Europe by the late Eocene (35 mya), and appear in Asia, an ...

. The

chalicothere Chalicotheres (from Greek '' chalix'', "gravel" and '' therion'', "beast") are an extinct clade of herbivorous, odd-toed ungulate (perissodactyl) mammals that lived in North America, Eurasia, and Africa from the Middle Eocene until the Early Plei ...

s survived the Oligocene epoch. A new genus of entelodont called '' Daeodon'' evolved in order to adapt to the new habitats and hunt the new prey animals of the Early Miocene epoch; it quickly became the top predator of

North America North America is a continent in the Northern Hemisphere and almost entirely within the Western Hemisphere. It is bordered to the north by the Arctic Ocean, to the east by the Atlantic Ocean, to the southeast by South America and the Car ...

. But it became extinct due to competition from ''

Amphicyon ''Amphicyon'' ("ambiguous dog") is an extinct genus of large carnivorous bone-crushing mammals, popularly known as bear dogs, of the family Amphicyonidae, subfamily Amphicyoninae, from the Burdigalian Epoch until the late Pliocene, with the creat ...

'', a newcomer from Eurasia. ''Amphicyon'' bested ''Daeodon'' because the bear-dog's larger brain, sharper teeth and longer legs built for longer chases helped it to overcome its prey.

External links

GeoWhen Database - Early Miocene
.01 Aquitanian (stage) Burdigalian 01 {{Geology-stub