Hyenas or Hyaenas (from Ancient Greek, hýaina) are feliform carnivoran mammals of the family Hyaenidae. With only four extant species (in three genera), it is the fifth-smallest biological family in the Carnivora, and one of the smallest in the class Mammalia. Despite their low diversity, hyenas are unique and vital components of most African ecosystems.
The four extant species are the striped hyena (Hyaena hyaena), the brown hyena (Hyaena brunnea), the spotted hyena (Crocuta crocuta), and the aardwolf (Proteles cristata).