During the Pleistocene Epoch, from about 2.5 million years ago to ten thousand years ago, the Earth went through a series of ice ages. Northern continents were periodically trapped beneath enormous glaciers spanning hundreds of kilometers. These glacial periods were punctuated by warmer periods called interglacials that saw the great glaciers retreat.
The wildlife in Europe during the Pleistocene was much more varied than what is presently seen. They include the cave hyena, as well as cave bears, cave lions, woolly rhinoceroses, and several elephants. Many of these species have adaptations for the cold, including larger body size, thicker fur, and body fat.
Cave hyenas have been known from fossil remains since the 18th century. They were present in most of Europe from about 300,000 years ago to about 11,000 years ago. Like living hyenas, cave hyenas resembled wolves with long muscular necks and strong forelimbs. In contract to their living relatives, they are larger and more robust.