Hyenas are the animals of the family Hyaenidae of suborder feliforms of the Carnivora. It is the fourth smallest biological family in the Carnivora (consisting of four species), and one of the smallest in the mammalia. Despite their low diversity, hyenas are unique and vital components to most African and some Asian ecosystems.
Hyenas have relatively short torsos, and are fairly massive and wolf-like in build, but have lower hind quarters, high withers and their backs slope noticeably downward toward their croups. The forelegs are high, while the hind legs are very short and their necks are thick and short. Their skulls superficially resemble those of large canids, but are much larger and heavier, with shorter facial portions. Hyenas are digitigrade, with the fore and hind paws having four digits each and sporting bulging pawpads.
Like canids, hyenas have short, blunt, non-retractable claws. Their pelage is sparse and coarse with poorly developed or absent underfur. Most species have a rich mane of long hair running from the withers or from the head. With the exception of the spotted hyena, hyaenids have striped coats. Their ears are large and have simple basal ridges. Their vertebral column, including the cervical region are of limited mobility. Hyenas have an additional pair of ribs than canids, and their tongues are rough like those of felids. Males in most hyena species are larger than females, though the spotted hyena is exceptional, as it is the female of the species that outweighs and dominates the male.
Their dentition is similar to that of the Felines, but is more specialised for consuming coarse food and crushing bones. The carnassials, especially the upper, are very powerful and are shifted far back to the point of exertion of peak pressure on the jaws. The other teeth, save for the underdeveloped upper molars, are powerful, with broad bases and cutting edges. The canines are short, but thick and robust. The strength of their jaws is such that both striped and spotted hyenas have been recorded to kill dogs with a single bite to the neck without breaking the skin. The spotted hyena is renowned for its strong bite proportional to its size, but a number of other animals (including the Tasmanian devil) are proportionately stronger. The aardwolf has greatly reduced cheek teeth, sometimes absent in the adult, but otherwise has the same dentition as the other three species.
Hyenas groom themselves often like felines. However, unlike other feliforms, they do not "wash" their faces. When attacked by lions or dogs, striped and brown hyenas will feign death, though the spotted hyena will defend itself ferociously. The spotted hyena is very vocal, producing a number of different sounds consisting of whoops, grunts, groans, lows, giggles, yells, growls, laughs and whines. The striped hyena is comparatively silent, its vocalisations being limited to a chattering laugh and howling.
Spotted hyena cubs are born almost fully developed, with their eyes open and erupting incisors and canines, though lacking adult markings. In contrast, striped hyena cubs are born with adult markings, closed eyes and small ears. Hyenas do not regurgitate food for their young and male spotted hyenas play no part in raising their cubs, though male striped hyenas do.
The striped hyena is primarily a scavenger, though it will occasionally attack and kill any defenseless animal it can overcome, and will supplement its diet with fruits. The spotted hyena, though it also scavenges occasionally, is an active pack hunter of medium to large sized ungulates, which it catches by wearing them down in long chases and dismembering them in a canid-like manner. The aardwolf is primarily an insectivore, specialised for feeding on termites, which it consumes by licking them up with its long, broad tongue. An aardwolf can eat 300,000 termites on a single outing. Hyenas are also known for their characteristic calls which sound like laughs.