Spotted Hyena

The spotted hyena (Crocuta crocuta), also known as the laughing hyena, is a species of hyena, currently classed as the sole member of the genus Crocuta, native to Sub-Saharan Africa. It is listed as being of least concern by the IUCN on account of its widespread range and large numbers estimated between 27,000 and 47,000 individuals. The species is, however, experiencing declines outside of protected areas due to habitat loss and poaching. The species may have originated in Asia, and once ranged throughout Europe for at least one million years until the end of the Late Pleistocene. The spotted hyena is the largest known member of the Hyaenidae, and is further physically distinguished from other species by its vaguely bear-like build, its rounded ears, its less prominent mane, its spotted pelt, its more dual purposed dentition, its fewer nipples and the presence of a pseudo-penis in the female. It is the only mammalian species to lack an external vaginal opening.
The spotted hyena is the most social of the Carnivora in that it has the largest group sizes and most complex social behaviours. Its social organisation is unlike that of any other carnivore, bearing closer resemblance to that of cercopithecine primates (baboons and macaques) with respect to group-size, hierarchical structure, and frequency of social interaction among both kin and unrelated group-mates. However, the social system of the spotted hyena is openly competitive rather than cooperative, with access to kills, mating opportunities and the time of dispersal for males depending on the ability to dominate other clan-members. Females provide only for their own cubs rather than assist each other, and males display no paternal care. Spotted hyena society is matriarchal; females are larger than males, and dominate them.
The spotted hyena is a highly successful animal, being the most common large carnivore in Africa. Its success is due in part to its adaptability and opportunism; it is primarily a hunter but may also scavenge, with the capacity to eat and digest skin, bone and other animal waste. In functional terms, the spotted hyena makes the most efficient use of animal matter of all African carnivores. The spotted hyena displays greater plasticity in its hunting and foraging behaviour than other African carnivores; it hunts alone, in small parties of 2–5 individuals or in large groups. During a hunt, spotted hyenas often run through ungulate herds in order to select an individual to attack. Once selected, their prey is chased over a long distance, often several kilometres, at speeds of up to 60 km/h.
The spotted hyena has a long history of interaction with humanity; depictions of the species exist from the Upper Paleolithic period, with carvings and paintings from the Lascaux and Chauvet Caves. The species has a largely negative reputation in both Western culture and African folklore. In the former, the species is mostly regarded as ugly and cowardly, while in the latter, it is viewed as greedy, gluttonous, stupid, and foolish, yet powerful and potentially dangerous. The majority of Western perceptions on the species can be found in the writings of Aristotle and Pliny the Elder, though in relatively unjudgemental form. Explicit, negative judgements occur in the Physiologus, where the animal is depicted as a hermaphrodite and grave robber. The IUCN's hyena specialist group identifies the spotted hyena's negative reputation as detrimental to the species' continued survival, both in captivity and the wild.
== Description ==
The spotted hyena has a strong and well developed neck and forequarters, but relatively underdeveloped hindquarters. The rump is rounded rather than angular, which prevents attackers coming from behind from getting a firm grip on it. The head is wide and flat with a blunt muzzle and broad rhinarium. In contrast to the striped hyena, the ears of the spotted hyena are rounded rather than pointed. Each foot has four digits, which are webbed and armed with short, stout and blunt claws. The paw-pads are broad and very flat, with the whole undersurface of the foot around them being naked. The tail is relatively short, being 300–350 mm (12–14 in) long, and resembles a pompom in appearance. Unusually among hyaenids, and mammals in general, the female spotted hyena is considerably larger than the male. Both sexes have a pair of anal glands which open into the rectum just inside the anal opening. These glands produce a white, creamy secretion which is pasted onto grass stalks by everting the rectum. The odour of this secretion is very strong, smelling of boiling cheap soap or burning, and can be detected by humans several metres downwind. The spotted hyena has a proportionately large heart, constituting close to 1% of its body weight, thus giving it great endurance in long chases. In contrast, a lion's heart makes up only 0.45–0.57 percent of its body weight. The now extinct Eurasian populations were distinguished from the modern African populations by their shorter distal extremities and longer humerus and femur.
The skull of the spotted hyena differs from that of the striped hyena by its much greater size and narrower sagittal crest. For its size, the spotted hyena has one of the most powerfully built skulls among the Carnivora. The dentition is more dual purposed than that of other modern hyena species, which are mostly scavengers; the upper and lower third premolars are conical bone-crushers, with a third bone-holding cone jutting from the lower fourth premolar. The spotted hyena also has its carnassials situated behind its bone-crushing premolars, the position of which allows it to crush bone with its premolars without blunting the carnassials. Combined with large jaw muscles and a special vaulting to protect the skull against large forces, these characteristics give the spotted hyena a powerful bite which can exert a pressure of 80 kgf/cm2 (1140 lbf/in²), which is 40% more force than a leopard can generate. The jaws of the spotted hyena outmatch those of the brown bear in bonecrushing ability, and free ranging hyenas have been observed to crack open the long bones of giraffes measuring 7 cm in diameter. A 63.1 kg (139 lb) spotted hyena is estimated to have a bite force of 565.7 newtons at the canine tip and 985.5 newtons at the carnassial eocone. One individual in a study was found to exert a bite force of 4,500 newtons on the measuring instruments.
The spotted hyena is the largest extant member of the Hyaenidae. Adults measure 95–165.8 cm (37–65 in) in body length, and have a shoulder height of 70–91.5 cm (28–36 in). Adult male spotted hyenas in the Serengeti weigh 40.5–55.0 kg (89–121 lb), while females weigh 44.5–63.9 kg (98–141 lb). Spotted hyenas in Zambia tend to be heavier, with males weighing on average 67.6 kg (149 lb), and females 69.2 kg (153 lb). Exceptionally large weights of 81.7 kg (180 lb) and 90 kg (198 lb) are known. It has been estimated that adult members of the now extinct Eurasian populations weighed 102 kg (225 lb).
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