Pachycrocuta was a genus of prehistoric hyenas. The largest and most well-researched species is Pachycrocuta brevirostris, colloquially known as the giant hyena as it is estimated to have averaged 110 kg (240 lb) in weight, the size of a lioness, making it the largest known hyena. Pachycrocuta first appeared during the late Pliocene about 3 million years ago and went extinct during the middle Pleistocene, 400,000 years ago.