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 stood about 90–100 cm (35–39 in) at the shoulder and it is estimated to have averaged 110 kg (240 lb) in weight, approaching the size of a lioness, making it the largest known hyena. Pachycrocuta first appeared during the late Pliocene about 3 million years ago and became extinct during the middle Pleistocene, 400,000 years ago.