Hyena

• 1. Introduction

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  Hyenas belong to a family with only four living species, each in its own genus, making Hyaenidae the fifth smallest family in the entire order Carnivora. That scarcity is deceptive. Despite their low diversity, hyenas function as unique and vital components of most African ecosystems. They look and hunt like dogs, running down prey with their teeth rather than their claws, yet hyenas are actually closer, phylogenetically, to felines and viverrids, a resemblance to canids produced entirely by convergent evolution. Ancient Greek gave the animal its name, hýaina, and human cultures living alongside hyenas have folded them into folklore for just as long, viewing them as frightening creatures linked to witchcraft, grave robbing and stolen livestock. How did an animal shaped so much like its rivals end up related to cats instead, and how did a family that nearly vanished become the continent's most efficient scavengers?

• 2. A Family Nearly Erased

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  Twenty two million years ago, in the jungles of Miocene Eurasia, the first hyenas appeared while most other early feliform species still lived in trees. Plioviverrops, one of the earliest described hyena species, was a lithe animal resembling a modern African civet, living in Eurasia between 20 and 22 million years ago and identifiable as a hyaenid mainly through the structure of its middle ear and teeth. Its descendants split into two branches, lightly built dog-like hyenas and robust bone-crushing hyenas. The dog-like branch thrived 15 million years ago, with more than 30 identified species, one of them, Ictitherium viverrinum, resembling a jackal; in some Miocene fossil sites their remains outnumber those of every other carnivore combined. A shift in climate 5 to 7 million years ago, worsened by canids crossing the Bering land bridge into Eurasia, drove most of them extinct. Only the insect-eating aardwolf survived from that dog-like line, while one other species, Chasmaporthetes ossifragus, managed to cross the land bridge in the opposite direction, becoming the only hyena ever to reach North America, where it survived for a time as a cheetah-like sprinter before most of the dog-like hyenas died out by 1.5 million years ago. The bone-crushing branch fared better. By 10 to 14 million years ago it had split off as its own group, arriving as the family Percrocutidae declined, and by 5 million years ago it had become the dominant scavenger of Eurasia, feasting on carcasses felled by sabre-toothed cats. One genus in that group, Pachycrocuta, weighed 110 kilograms and could splinter the bones of elephants; in the early Middle Pleistocene it was replaced by the smaller genera Crocuta and Hyena.

• 3. Four Survivors

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  Four species remain today: the striped hyena, the brown hyena, the spotted hyena and the aardwolf. The aardwolf traces its ancestry straight back to Plioviverrops 15 million years ago, the sole survivor of the dog-like lineage, and its success likely rests on an insectivorous diet that faced no competition from the canids arriving from North America, since its digestive system was already suited to digesting the terpene excretions of soldier termites. The striped hyena may descend from Hyaenictitherium namaquensis of Pliocene Africa; its fossils are common there, with records reaching back to the Villafranchian, and their absence from the Mediterranean suggests it only spread into Eurasia after spotted hyenas went extinct in Asia at the end of the Ice Age. It was once widespread in France and Germany during the Pleistocene, and turns up at Montmaurin, at Hollabrunn in Austria, in the Furninha Cave in Portugal and in the Genista Caves in Gibraltar, where the European form matched the brown hyena in size. The spotted hyena split from the striped and brown lines 10 million years ago, descending from the Indian species Crocuta sivalensis of the Villafranchian; increasing competition over carcasses likely pushed its ancestors to hunt in teams, and sharp carnassial teeth behind their crushing premolars let them kill prey outright rather than waiting for it to die, turning them into pack hunters as well as scavengers. Spreading out of its homeland during the Middle Pleistocene, the spotted hyena colonised a vast range stretching from Europe to southern Africa and China, before disappearing from Europe, a retreat once blamed solely on the end of the last glacial period and the spread of closed forest, though researchers now believe human pressure played a role too, tied to the broader pattern of late Quaternary extinctions. Genetic study points to further explanations: an expansion or duplication of the olfactory receptor gene family appears in all four living species, likely behind their specialised feeding habits, while the spotted, striped and brown hyenas each show expansion in immune-related gene families tied to scavenging, along with mutations in the digestion genes ASH1L, PTPN5, PKP3 and AQP10, one of which, PTPN5, also affects bone mineralisation. Aardwolves show their own signature, expansion in the Lipocalin and UDP Glucuronosyltransferase gene families linked to processing toxins from the termite genus Trinervitermes, alongside mutations in the craniofacial genes GARS, GMPR, STIP1, SMO and PAPSS2.

• 4. A Body Built to Crush

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  A hyena's torso runs short and fairly massive, wolf-like overall but with lower hindquarters and high withers, so the back slopes noticeably down toward the rump. The forelegs stand tall while the hind legs stay short, and the neck is thick. Their skulls resemble those of large canids on the surface, but run much larger and heavier with shorter facial portions, and like canids they walk digitigrade, with four digits on each bulging, pawpadded foot and short, blunt, non-retractable claws. Their coats run sparse and coarse, mostly without underfur, though most species carry a rich mane running from the withers or the head; every species but the spotted hyena wears stripes, a trait likely inherited from viverrid ancestors. Hyenas carry one more pair of ribs than canids, rough tongues like felids and viverrids, and no baculum, and in the spotted hyena alone the female outweighs and dominates the male, with external genitalia that closely resemble the male's own. Their teeth take the crushing further than any canid's: the upper carnassials sit unusually far back, at the point of peak jaw pressure, while the mandibles are far stronger at the canine teeth than a canid's, since hyenas crack bone with their front teeth and premolars rather than the rear molars canids use. That strength lets both striped and spotted hyenas kill dogs with a single bite to the neck without breaking the skin, and though the spotted hyena's bite is renowned for its strength relative to body size, a handful of other animals, including the Tasmanian devil, are proportionately stronger still. The aardwolf alone has lost most of this equipment, its cheek teeth reduced and sometimes absent entirely in adults. Hyenas lack scent glands near the groin but carry a pouch of naked skin at the anus, fed by large glands whose secretion, a white, creamy paste smelling of boiling cheap soap or of burning, hyenas smear onto grass stalks to mark territory, a smell humans can detect several meters downwind.

• 5. Habits That Set Them Apart

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  A hyena grooming itself looks almost feline, licking its genitals while sitting on its lower back with one leg pointed straight up, a posture shared with viverrids rather than dogs. Hyenas never lift a leg to urinate, since urination carries no territorial meaning for them; they rely on their anal glands instead, a habit shared with viverrids and mustelids but absent in canids and felids. When lions or dogs attack, striped and brown hyenas will feign death, while the spotted hyena fights back. The spotted hyena is famously loud, producing whoops, grunts, groans, giggles, yells, growls, laughs and whines, while the striped hyena stays mostly quiet, limited to a chattering laugh and a howl. Mating pairs of hyenas complete a series of short couplings with brief pauses, unlike the single drawn-out copulation typical of canids, and spotted hyena cubs arrive almost fully developed, eyes open and incisors and canines already erupting, though without adult markings yet, while striped hyena cubs are born already marked but with closed eyes and small ears; neither species regurgitates food for its young, and male spotted hyenas take no part in raising cubs, though male striped hyenas do. Diet splits the family further. The striped hyena scavenges as its main strategy but will also kill what it can overcome and round out its diet with fruit, while the spotted hyena, an active pack hunter of medium and large ungulates, runs prey down over long chases and dismembers it much as a canid would, killing as many as 95 percent of the animals it eats. The aardwolf feeds almost entirely on termites of the genus Trinervitermes and Hodotermes, lapping them up with a long, broad tongue, and can eat 300,000 Trinervitermes in a single outing. Except for the aardwolf, hyenas will drive lions and other larger predators off their own kills, a boldness at odds with the animal's reputation for cowardice in popular culture, and they operate mainly at night, though the highly social spotted hyena is the only species that lives in large groups, since striped and brown hyenas at most form family units that gather at kills. Spotted hyenas rank among the few mammals besides bats known to survive rabies infection, showing little disease-induced death during outbreaks that devastate other carnivores nearby, likely thanks to a high concentration of antibodies in their saliva, though beyond that little is understood about their immune system, and even less about the immune systems of the other three species.

• 6. Feared in Folklore

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  Depictions of the spotted hyena shift with the ethnic group telling the story, and in West Africa it is often hard to tell whether spotted or striped hyenas inspired a given tale, since both species frequently share the same local names. West African stories among the Beng of Côte d'Ivoire sometimes cast the spotted hyena as a bad Muslim challenging local animism, while in East Africa, Tabwa mythology portrays it instead as a solar animal that first carried the sun to warm a cold earth; elsewhere in West Africa the hyena more often stands for immorality, dirty habits and the reversal of normal life. In Tanzania, some believe witches ride spotted hyenas as mounts, and in the Mtwara Region a child born at night while a hyena cries is thought likely to grow into a thief, while hyena feces there are believed to help children walk early, leading some to wrap the dung in a child's clothing. The Kaguru of Tanzania and the Kujamaat of southern Senegal regard hyenas as inedible, greedy hermaphrodites, and a mythical tribe called the Bouda, said to exist in Mansôa as well, is reputed to transform into hyenas, these werehyenas killed on discovery and said never to revert to human shape once dead. Middle Eastern literature more often frames the striped hyena as a symbol of treachery and stupidity, and a physical incarnation of jinns; the Arab writer al-Qazwīnī, who lived from 1204 to 1283, wrote in 'Ajā'ib Al-Makhlūqāt of a tribe called al-Ḍabyūn, or hyena people, claiming that a hyena could single one of them out of a crowd of 1,000 and eat him. A Persian medical treatise from 1376 described how to cure cannibalistic people called kaftar, said to be half man and half hyena, while the writer al-Damīrī, in Ḥawayān al-Kubrā from 1406, called striped hyenas vampiric creatures that attacked people at night to drink blood from their necks, attacking only the brave, and Arab folklore held that hyenas could mesmerise victims with their eyes or their pheromones. Greeks held a similar belief until the close of the 19th century, that the undestroyed bodies of werewolves haunted battlefields as vampiric hyenas drinking the blood of dying soldiers. In Afghanistan, India and Palestine the striped hyena's image grows more varied still, feared yet also tied to love and fertility, giving rise to love medicines made from its body parts, and among the Baluch and in northern India, witches or magicians are said to ride striped hyenas by night. The Bible itself mentions the striped hyena, and the Arabic word for the animal, ḍab or ḍabu, survives in the names of a valley in Israel, Shaqq-ud-Diba and Wadi-Abu-Diba, meaning cleft or valley of the hyenas, which some scholars connect to the Valley of Tsebo`im named in 1 Samuel 13:18; in modern Hebrew, the same word, tsavua, means both hyena and hypocrite, and although the Authorized King James Version renders the term ayit tsavua in Jeremiah 12:9 as speckled bird, Henry Baker Tristram argued it more likely meant hyena. The spotted hyena's laugh-like call turns up as a stock simile in works including The Cobbler's Prophecy from 1594, Webster's Duchess of Malfi from 1623 and Shakespeare's As You Like It. The South African poet N. P. van Wyk Louw evoked a sinister, ominous presence in his allegorical poem Die Strandjutwolf, about the brown hyena.

• 7. When Hyenas Hunt People

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  Striped hyenas normally show extreme timidity around people, though they can turn bold at night, and on rare occasions have preyed on humans directly. Only the spotted and striped hyenas have ever been documented as man-eaters, and the pattern reaches back into prehistory: human hair has turned up in fossilized hyena dung dating between 195,000 and 257,000 years old. Some paleontologists argue that competition and predation from cave hyenas in Siberia delayed human colonization of Alaska, since hyenas may have stolen human kills or raided camps for the young and weak, and the oldest known Alaskan human remains coincide closely with the extinction of cave hyenas there. Hyenas readily scavenge human corpses; in Ethiopia they fed extensively on victims of the 1960 attempted coup and of the Red Terror, and in southern Sudan, attacks on living people increased during the Second Sudanese Civil War, when corpses lay readily available. Man-eating spotted hyenas tend to be unusually large; a pair blamed for killing 27 people in Mulanje, Malawi, in 1962 weighed 72 and 77 kilograms after being shot, and a 1903 report describes spotted hyenas in the Mzimba district of Angoniland waiting at dawn outside huts to attack residents as they opened their doors. Victims skew toward women, children and the sick or infirm; Theodore Roosevelt, writing in 1908 and 1909 from Uganda, described spotted hyenas regularly killing sufferers of African sleeping sickness as they slept outside in camps. Malawi in particular fears the spotted hyena, especially in the hot season when people sleep outdoors; the Phalombe plain recorded five deaths in 1956, five more in 1957 and six in 1958, a pattern that continued until eight people were killed in 1961, with attacks concentrated in September, when bush fires made hunting wild game harder for the hyenas. A 2004 news report counted 35 people killed by spotted hyenas over 12 months along a 20 kilometer stretch of road in Mozambique near the Tanzanian border. In the 1880s, a hyena attacked humans, especially sleeping children, over three years in Turkey's Iğdır Province, wounding 25 children and 3 adults in a single year, and further attacks followed in the South Caucasus, notably in 1908. Striped hyenas killed children sleeping in courtyards in Azerbaijan during the 1930s and 1940s, and in 1942 one mauled a sleeping guard in his hut at Qalıncaq. Children have been taken by night in Turkmenistan's Bathyz Nature Reserve, and a further child attack was reported near Serakhs in 1948. India recorded several incidents too: in 1962, nine children were believed taken by hyenas over six weeks in Bhagalpur, in Bihar State, and 19 children up to age four were killed in Karnataka in 1974, though a five-year survey of wild animal attacks in Madhya Pradesh found hyenas responsible for only three attacks, fewer deaths than those caused by wolves, gaur, boar, elephants, tigers, leopards and sloth bears in the same period.

• 8. Hyenas as Food and Medicine

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  In Somalia, hyenas have occasionally served as both food and medicine, a practice some Muslims consider halal under Islam while others dispute it. The custom traces back to the Ancient Greeks and Romans, who believed that different parts of a hyena's body could ward off evil and secure love and fertility, a use that has persisted, in altered form, into the present day.