Cave hyena - Misplaced Pages

Extinct subspecies of carnivore

Cave hyena Temporal range: Middle to Late Pleistocene, 0.5–0.020 Ma PreꞒ Ꞓ O S D C P T J K Pg N ↓

Crocuta crocuta spelaea skeleton from the Muséum de Toulouse.
Scientific classification
Domain:	Eukaryota
Kingdom:	Animalia
Phylum:	Chordata
Class:	Mammalia
Order:	Carnivora
Suborder:	Feliformia
Family:	Hyaenidae
Genus:	Crocuta
Species:	C. crocuta
Subspecies:	†C. c. spelaea
Trinomial name
†Crocuta crocuta spelaea Goldfuss, 1823

Cave hyena (Crocuta (crocuta) spelaea and Crocuta (crocuta) ultima) are extinct species or subspecies of hyena known from Eurasia, which ranged from Western Europe to eastern Asia and Siberia during the Pleistocene epoch. It is well represented in many European caves, primarily dating to the Last Glacial Period. It was an apex predator that preyed on large mammals (primarily large ungulates, such as wild horse and aurochs), and was responsible for the accumulation of hundreds of large Pleistocene mammal bones in areas including horizontal caves, sinkholes, mud pits, and muddy areas along rivers.

Often treated as subspecies or populations of the living African spotted hyena (Crocuta crocuta) to which they were closely related and heavily resembled, genetic evidence from the nuclear genome suggests that Eurasian Crocuta populations (including the west Eurasian Crocuta crocuta spelaea and Asian Crocuta crocuta ultima) were highly genetically divergent from African populations (having estimated to have split over 1 million years ago), with evidence suggesting limited interbreeding between Eurasian cave and African spotted hyenas. Some authors have suggested that the two subspecies should be raised to species level as Crocuta spelaea and Crocuta ultima.

Cave hyenas coexisted in Europe alongside both Neanderthals and modern humans. Evidence suggests that they consumed the remains of Neanderthals at least on occasion, with cave hyenas also being recorded in cave art.

The cause of the cave hyena's extinction is not fully understood, though it could have been due to a combination of factors, including human activity, diminished quantities of prey animals, and climate change.

Description

The size of cave hyenas varied depending on environment, with populations inhabiting colder climates having a larger body size than those inhabiting more temperate climates, an example of Bergmann's rule. A 2017 study estimated that on average cave hyenas weighed approximately 88 kilograms (194 lb), around 60% heavier than living spotted hyenas. In comparison to living spotted hyenas, some of the bones of the limbs are more robust (proportionally thicker and shorter), with the ulna being more curved. In the skull, the first and second upper premolars contact each other, while in living spotted hyenas they are separated by a diastema (gap), though collectively the differences between the skeletal anatomy of cave hyenas and living spotted hyenas are "relatively minor". The endocast (brain cavity) also shows differences between from that of the spotted hyena, with the living spotted hyena having a better developed front part of the brain, which may suggest differences in behaviour. Evidence from cave art suggests that cave hyenas had a similar physical appearance to living spotted hyenas.

Ecology

While "cave hyenas" did use caves, they were not confined to them, being present where caves were absent, and where present only using caves intermittently.

The cave hyena's diet differed little from contemporary African spotted hyenas, with the bones of prey often being cracked open/crushed in order to feed on the interior marrow, as is done by living spotted hyenas.

The diet of the cave hyena is thought to have primarily consisted of large ungulates like wild horse, aurochs, steppe bison, Irish elk/giant deer, wild boar, red deer and reindeer, with larger herbivores like the woolly rhinoceros and woolly mammoth probably being scavenged after death, with their young perhaps sometimes being targeted.

Wild horse are common in Late Pleistocene European cave hyena dens, implying that they were frequent prey, as zebras are for modern African spotted hyenas. In karst cave sites in the Czech Republic which accumulated during the Last Glacial Period, wild horses as well as woolly rhinoceros are the most common remains in cave hyena dens (though this to a significant degree probably reflects the durability of woolly rhinoceros bones making them able to be identified), with other remains including steppe bison, red deer, reindeer, European wild ass, chamois, alpine ibex, and cave bears (who may have been scavenged after dying in the caves). At the Fouvent-Saint-Andoche karst in France, a similar assemblage is found, albeit also including juvenile woolly mammoths, reflecting the similar cold conditions in both regions during the Last Glacial Period. At the Grotta Paglicci den in southern Italy, the assemblage is dominated by European fallow deer, red deer, roe deer and aurochs. At San Teodoro cave in northern Sicily which is a well known hyena den, remains of herbivores likely accumulated in the cave by hyenas include those of aurochs, steppe bison (with aurochs seeming to predominate over bison), European wild ass, wild boar, red deer, and the endemic dwarf elephant Palaeoloxodon mnaidriensis. At Kirkdale Cave in Yorkshire, northern England which dates to the Last Interglacial when Europe had a temperate climate similar to modern times, the assemblage includes juvenile straight-tusked elephant, Irish elk, red deer, European fallow deer, bison, and the narrow-nosed rhinoceros. At the Manot Cave site in Israel, the bone assemblage accumulated by cave hyenas is predominantly Persian fallow deer, as well as to a lesser extent goats, aurochs and equines. At Wezmeh Cave in the Zagros Mountains of western Iran, dating to the Last Glacial Period, remains include mouflon, wild goat, red deer, aurochs, wild boar, gazelles, and the narrow-nosed rhinoceros. Cave hyenas also appear to have extensively engaged in cannibalism, demonstrated as numerous sites.

Cave hyenas likely came into conflict with cave lions (which despite their name, probably only rarely if ever used caves) over carcasses, with remains of cave lions found in European cave deposits possibly being the result of being brought into the cave by cave hyenas. A significant number of these cave lion remains do not bear any evidence of consumption, which may suggest that like living spotted hyenas, they did not generally consume the remains of lions after killing them.

History of discovery and classification

Although the first full account of the cave hyena was given by Georges Cuvier in 1812, skeletal fragments of the cave hyena have been described in scientific literature since the 18th century, though they were frequently misidentified. The first recorded mention of the cave hyena in literature occurs in Kundmann's 1737 tome Rariora Naturæ et Artis, where the author misidentified a hyena's mandibular ramus as that of a calf. In 1774, Esper erroneously described hyena teeth discovered in Gailenreuth as those of a lion, and in 1784, Collini described a cave hyena skull as that of a seal. The past presence of hyenas in Great Britain was revealed after William Buckland's examination of the contents of Kirkdale Cave, which was discovered to have once been the location of several hyena den sites. Buckland's findings were followed by further discoveries by Clift and Whidbey in Oreston, Plymouth.

In his own 1812 account, Cuvier mentioned a number of European localities where cave hyena remains were found, and considered it a different species from the spotted hyena on account of its superior size. He elaborated his view in his Ossemens Fossiles (1823), noting how the cave hyena's digital extremities were shorter and thicker than those of the spotted hyena. His views were largely accepted throughout the first half of the 19th century, finding support in de Blainville and Richard Owen among others. Further justifications in separating the two animals included differences in the tubercular portion of the lower carnassial. Boyd Dawkins, writing in 1865, was the first to definitely cast doubt over the separation of the spotted and cave hyena, stating that the aforementioned tooth characteristics were consistent with mere individual variation. Writing again in 1877, he further stated after comparing the two animals' skulls that there are no characters of specific value.

Genetics

Analysis of the mitochondrial genomes of Eurasian Crocuta specimens shows no clear separation from African lineages. However, an analysis of full nuclear genomes of both European and East Asian cave hyenas published in 2020 suggests that African and Eurasian Crocuta populations were largely separate, having estimated to have diverged from each other around 2.5 million years ago, closely corresponding to the age of the earliest Crocuta specimens in Eurasia, which are around 2 million years old from China. The nuclear genome results also suggested that the European and East Asian populations (often assigned to the separate subspecies C. crocuta ultima) were strongly genetically divergent 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 these 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 East Asian Crocuta, suggesting gene flow between the two groups after the split between the East Asian and European populations. Some authors have suggested that the two subspecies should be raised to species level as Crocuta spelaea and Crocuta ultima. A 2024 study of a cave hyena genome from Sicily found that as with the 2020 study, there was strong genetic separation between Eurasian cave and African spotted hyenas, but unlike the 2020 study, there was no robust support for a basal split between East Asian/Siberian and European cave hyenas, with the Sicilian cave hyena found to be the earliest diverging cave hyena lineage, with less interbreeding with African hyenas than other European cave hyenas.

Distribution

Crocuta first appeared outside of Africa in Asia during the Early Pleistocene around 2 million years ago, before arriving in Europe at the beginning of the Middle Pleistocene around 800,000 years ago. Crocuta was widely distributed across northern Eurasia during the Middle-Late Pleistocene, spanning from the Iberian Peninsula, Britain and Ireland in the West, across southern Siberia, Mongolia and northern China to the Pacific Coast of the Russian Far East. C. c. ultima at times ranged as far southeast as Guangxi and Taiwan in southern China, as well as Thailand and Laos in Southeast Asia, while C. c. spelaea ranged into the Middle East, as far south as the Judaean Desert and as far east as the Zagros Mountains of western Iran. The northernmost records are from the banks of the Vilyuy River in Northeast Siberia, with indirect evidence of feeding on woolly rhinoceros carcasses suggesting cave hyenas may have reached the far northeast of Siberia near the Arctic circle.

Relationships with hominids

Interactions

Kills partially processed by Neanderthals and then by cave hyenas indicate that hyenas would occasionally steal Neanderthal kills; and cave hyenas and Neanderthals competed for cave sites. Many caves show alternating occupations by hyenas and Neanderthals. There is fossil evidence of humans in Middle Pleistocene Europe butchering and presumably consuming hyenas. At a number of cave hyena den sites, the remains of Neanderthals have been found showing evidence of having been gnawed on by the hyenas, this may be the result of cave hyenas scavenging Neanderthal burials, though some of these remains may also be the result of cave hyenas attacking and killing Neanderthals.

In rock art

The cave hyena is depicted in a few examples of Upper Palaeolithic rock art in France. A painting from the Chauvet Cave depicts a hyena outlined and represented in profile, with two legs, with its head and front part with well distinguishable spotted coloration pattern. Because of the specimen's steeped profile, it is thought that the painting was originally meant to represent a cave bear, but was modified as a hyena. In Lascaux, a red and black rock painting of a hyena is present in the part of the cave known as the Diverticule axial, and is depicted in profile, with four limbs, showing an animal with a steep back. The body and the long neck have spots, including the flanks. An image on a cave in Ariège shows an incompletely outlined and deeply engraved figure, representing a part of an elongated neck, smoothly passing into part of the animal's forelimb on the proximal side. Its head is in profile, with a possibly re-engraved muzzle. The ear is typical of the spotted hyena, as it is rounded. An image in the Le Gabillou Cave in Dordogne shows a deeply engraved zoomorphic figure with a head in frontal view and an elongated neck with part of the forelimb in profile. It has large round eyes and short, rounded ears which are set far from each other. It has a broad, line-like mouth that evokes a smile. Though originally thought to represent a composite or zoomorphic hybrid, it is probable it is a spotted hyena based on its broad muzzle and long neck. The relative scarcity of hyena depictions in Paleolithic rock art has been theorised to be due to the animal's lower rank in the animal worship hierarchy; the cave hyena's appearance was likely unappealing to Ice Age hunters, and it was not sought after as prey. Also, it was not a serious rival like the cave lion or bear, and it lacked the impressiveness of the mammoth or woolly rhino.

Extinction

A 2014 study concluded that the youngest well-dated remains of cave hyenas in Europe date to around 31,000 years ago. A later 2020 study concluded that cave hyenas may have persisted as late as 7,000 years ago in the southern Iberian Peninsula based on radiocarbon dating of likely hyena coprolites found in caves in the region, but suggested that the dates should be considered with caution due to potential issues with contamination. A 2021 study found the youngest specimens in East Asia date to around 20,000 years ago. Potential causal factors for extinction include decreasing temperatures, competition with other carnivores, including humans for food and living space, and decreased prey abundance. Evidence suggests that climate change alone cannot account for the cave hyena's extinction in Europe and that other factors, such as human activity and decreasing prey abundance, are necessary to explain it.

Gallery

Cranium from Wookey Hole, now in Taunton Museum
Skull from Wookey Hole, now in Taunton Museum
Anterior and posterior views of the right forefoot, from Tor Bryan Caves near Torquay, now kept in British Museum
Anterior and posterior views of the right hind foot, from Tor Bryan Caves near Torquay, now kept in British Museum.
Permanent dentition of a Pleistocene cave hyena from Tor Bryan Caves near Torquay, now kept in British Museum.
Permanent dentition, from Tor Bryan Caves near Torquay (now kept in British Museum), Creswell Caves in Derbyshire (now kept in Manchester's Owen College Museum), Kirkdale Cave and Wookey Hole (now kept in Oxford Museum).
Jaws and cranium from Kent's Hole, Torquay (now in British Museum) and Wookey Hole (now in Taunton Museum).
Vertebrae from Wookey Hole (now in Taunton Museum).
Vertebrae from Wookey Hole (now in Taunton Museum).
Vertebrae from Wookey Hole (now in Taunton Museum).
Pelvis from Wookey Hole (now in Taunton Museum).
Scapula from Creswell Caves, Derbyshire (now in Owens College Museum, Manchester).