Spotted hyena
The spotted hyena, also known as the laughing hyena, is a hyena species, currently classed as the sole extant member of the genus Crocuta, native to sub-Saharan Africa. It is listed as being of least concern by the IUCN due to 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. Populations of Crocuta, usually considered a subspecies of Crocuta crocuta, known as cave hyenas, roamed across Eurasia for at least one million years until the end of the Late Pleistocene. The spotted hyena is the largest extant member of the Hyaenidae, and is further physically distinguished from other species by its vaguely bear-like build, rounded ears, less prominent mane, spotted pelt, more dual-purposed dentition, fewer nipples, and pseudo-penis. It is the only placental mammalian species where females have a pseudo-penis and 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 with respect to group size, hierarchical structure, and frequency of social interaction among both kin and unrelated group-mates. The social system of the spotted hyena is openly competitive, with access to kills, mating opportunities and the time of dispersal for males depending on the ability to dominate other clan-members and form ally networks. Females provide only for their own cubs rather than assist each other, and males display no paternal care. However, the spotted hyena is also very cooperative with their clan-mates; often hunting, eating, and resting together, and making use of their numeracy and communication skills to fight off a common enemy. 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 to select an individual to attack. Once selected, their prey is chased over a long distance, often several kilometres, at speeds of up to.
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 unjudgmental form. Explicit, negative judgments 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.
Etymology and naming
The spotted hyena's scientific name Crocuta was once widely thought to be derived from the Latin loanword crocutus, which translates as 'saffron-coloured one', in reference to the animal's fur colour. This was proven to be incorrect, as the correct spelling of the loanword would have been Crocāta, and the word was never used in that sense by Graeco-Roman sources. Crocuta actually comes from the Ancient Greek word Κροκόττας, which is derived from the Sanskrit, which in turn originates from . The earliest recorded mention of Κροκόττας is from Strabo's Geographica, where the animal is described as a mix of wolf and dog native to Ethiopia.From Classical antiquity until the Renaissance, the spotted and striped hyena were either assumed to be the same species, or distinguished purely on geographical, rather than physical, grounds. Hiob Ludolf, in his Historia aethiopica, was the first to clearly distinguish the Crocuta from Hyaena as different animals, though he never had any first hand experience of the species, having gotten his accounts from an Ethiopian intermediary. Confusion still persisted over the exact taxonomic nature of the hyena family in general, with most European travelers in Ethiopia referring to hyenas as "wolves". This partly stems from the Amharic word for hyena, , which is linked to the Arabic word 'wolf'.
The first detailed first-hand descriptions of the spotted hyena by Europeans come from Willem Bosman and Peter Kolbe. Bosman, a Dutch tradesman who worked for the Dutch West India Company at the Gold Coast from 1688 to 1701, wrote of Jakhals, of Boshond whose physical descriptions match the spotted hyena. Kolben, a German mathematician and astronomer who worked for the Dutch East India Company in the Cape of Good Hope from 1705 to 1713, described the spotted hyena in great detail, but referred to it as a "tigerwolf", because the settlers in southern Africa did not know of hyenas, and thus labelled them as "wolves".
Bosman and Kolben's descriptions went largely unnoticed until 1771, when the Welsh naturalist Thomas Pennant used the descriptions and his personal experience with a captive specimen as a basis for consistently differentiating the spotted hyena from the striped in his Synopsis of Quadrupeds. The description given by Pennant was precise enough to be included by Johann Erxleben in his Systema regni animalis by simply translating Pennant's text into Latin. Crocuta was finally recognised as a separate genus from Hyaena in 1828.
Taxonomy, origins and evolution
Unlike the striped hyena, for which a number of subspecies were proposed in light of its extensive modern range, the spotted hyena is a genuinely variable species, both temporally and spatially. Its range once encompassed almost all of Africa and Eurasia, and displayed a large degree of morphological geographic variation, which led to an equally extensive set of specific and subspecific epithets. It was gradually realised that all of this variation could be applied to individual differences in a single subspecies. In 1939, biologist L Harrison Matthews demonstrated through comparisons between a large selection of spotted hyena skulls from Tanzania that all the variation seen in the then recognised subspecies could also be found in a single population, with the only set of characters standing out being pelage and size. When fossils are taken into consideration, the species displayed even greater variation than it does in modern times, and a number of these named fossil species have since been classed as synonymous with Crocuta crocuta, with firm evidence of there being more than one species within the genus Crocuta still lacking.File:Crocuta silvanensis skull.png|thumb|Skull of Crocuta sivalensis, an extinct Indian hyena proposed by Björn Kurtén as being the ancestor of the modern spotted hyena
The ancestors of the genus Crocuta diverged from Hyaena 10 million years ago. The ancestors of the spotted hyena probably developed social behaviours in response to increased pressure from other predators on carcasses, which forced them to operate in teams. At one point in their evolution, spotted hyenas developed sharp carnassials behind their crushing premolars; this rendered waiting for their prey to die no longer a necessity, as is the case for brown and striped hyenas, and thus they became pack hunters as well as scavengers. They began forming increasingly larger territories, necessitated by the fact that their prey was often migratory and long chases in a small territory would have caused them to encroach into another clan's land. It has been theorised that female dominance in spotted hyena clans could be an adaptation in order to successfully compete with males on kills, and thus ensure that enough milk is produced for their cubs. Another theory is that it is an adaptation to the length of time it takes for cubs to develop their massive skulls and jaws, thus necessitating greater attention and dominating behaviours from females.
Both Björn Kurtén and Camille Arambourg promoted an Asiatic origin for the species; Kurtén focussed his arguments on the Plio-Pleistocene taxon Crocuta sivalensis from the Siwaliks, a view defended by Arambourg, who nonetheless allowed the possibility of an Indo-Ethiopian origin. This stance was contested by Ficarelli and Torre, who referred to evidence of the spotted hyena's presence from African deposits dating from the early Pleistocene, a similar age to the Asian C. sivalensis. Modern scholarship supports an African origin for the genus, with the earliest fossils of the genus Crocuta dating to the early Pliocene of Africa, around 3.63 to 3.85 million years ago.
The earliest known fossil record of Crocuta crocuta in Africa is from the Cradle of Humankind, specifically from the Sterkfontein Member 4 which is dated approximately in minimum, and it is also common in deposits dated between. Analysis of the mitochondrial genomes of Eurasian Crocuta specimens shows no clear separation from African lineages. It also suggests that modern spotted hyena populations descend from a widely ranging Afro-Eurasian population that was only recently reduced in range to Africa exclusively. However, analysis of the full nuclear genome suggests that Late Pleistocene African and Eurasian Crocuta populations were largely separate, having estimated to have diverged from each other around, closely corresponding to the age of the earliest Crocuta specimens in Eurasia, which are around from China. The nuclear genome results also suggest that the European and Asian populations were distinct from each other, but were more closely related to each other overall than to African Crocuta populations. Analysis of the nuclear genome suggests that there had been interbreeding between African and Eurasian populations for some time after the split, which likely explains the discordance between the nuclear and mitochondrial genome results, with the mitochondrial genomes of African and European Crocuta more closely related to each other than to Asian Crocuta, suggesting gene flow between the two groups after the split between the Asian and European populations.
Its appearance in Europe and China coincided with the decline and eventual extinction of Pachycrocuta brevirostris, the giant short-faced hyena. As there is no evidence of environmental change being responsible, it is likely that the giant short-faced hyena became extinct due to competition with the spotted hyena.