Ice age mammals

After the extinction of the non-bird dinosaurs at the end of the Cretaceous, mammals expanded to fill a wide range of ecological roles during the Cenozoic Era. The most familiar of these later animals are the large mammals of the Pleistocene epoch, the series of glacial periods commonly called the ice ages, which ended around eleven and a half thousand years ago. During the colder phases, ice sheets covered much of the northern continents and a cold, dry grassland known as the mammoth steppe stretched across the far north.

This environment supported a distinctive assembly of large herbivores and predators, collectively called megafauna. The woolly mammoth, a relative of modern elephants, was insulated by a thick coat of hair and a layer of fat and used its long curved tusks to sweep snow from vegetation. The woolly rhinoceros grazed the same steppe, and other animals of the period included giant deer, cave bears, cave lions and sabre-toothed cats. Frozen carcasses preserved in permafrost have given paleontologists unusually complete information about the soft tissue, stomach contents and even hair colour of some of these species.

Most of the largest ice age mammals died out as the last glacial period ended. The causes are debated and probably combined: rapid warming changed the vegetation and shrank the cold steppe, while expanding human populations hunted many large species. Paleoecology and the study of fossils, tracks and other animal traces help reconstruct how these communities lived and why they vanished.

Frequently asked questions

Were ice age mammals dinosaurs?

No. They were mammals that lived long after the non-bird dinosaurs went extinct, during the Pleistocene ice ages of the Cenozoic Era.

How was the woolly mammoth adapted to the cold?

It had a thick coat of long hair, a layer of insulating fat, small ears to reduce heat loss, and tusks it could use to clear snow from plants.

Why did the megafauna become extinct?

Likely a combination of rapid climate warming that transformed their grassland habitat and hunting pressure from growing human populations.