Cave hyenas (Crocuta (crocuta) spelaea and Crocuta (crocuta) ultima) are extinct species or subspecies of hyena known from Eurasia, which ranged from Western Europe and West Asia to eastern Siberia, East Asia and Southeast Asia during the Pleistocene epoch. They are well represented in many caves, primarily dating to the Last Glacial Period. Cave hyenas served as apex predators that preyed on large mammals (primarily large ungulates, such as wild horse, steppe bison and aurochs), and were responsible for the accumulation of hundreds of large Pleistocene mammal bones in areas including horizontal caves, sinkholes, mud pits, and muddy areas along rivers. It was one of the main apex predators of northern Eurasian ecosystems alongside the cave lion (Panthera spelaea), with the two species likely engaging in hostile conflict over carcasses. Much like African spotted hyenas, they likely lived in clans.
Often treated as subspecies or populations of the living African spotted hyena (Crocuta crocuta) to which they were closely related and heavily resembled (though considerably larger in size), 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; thus, the species is an example of Bergmann's rule. A 2017 study estimated that on average cave hyenas weighed approximately , 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 dental anatomy of Asian C. (crocuta) ultima, has been described as indistinguishable from that of European C. (Crocuta) spelaea. The endocast (brain cavity) of cave hyenas were more similar to spotted hyenas than brown or striped hyenas. Compared to spotted hyenas, the cave hyenas had a larger and elongated brain, as well as having smaller relative anterior regions. Evidence from cave art suggests that cave hyenas had a similar physical appearance to living spotted hyenas, with a spotted pelt.
Distribution and evolution
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, around the time of the extinction of the "giant hyena" Pachycrocuta brevirostris in the region.
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 and North Korea. They ranged as far south as Uzbekistan in Central Asia and Azerbaijan in the Caucasus.Baryshnikov G. 1999. Chronological and geographical variability of Crocuta spelaea (Carnivora, Hyaenidae) from the Pleistocene of Russia. Deinsea 6:1155–74 C. c. ultima at times ranged as far southeast as Guangxi and Taiwan in southern China, as well as Thailand (southwards to peninsular Thailand), Cambodia and Laos in Southeast Asia. Crocuta hyenas also ranged into the Middle East, as far south as the Judaean Desert in Israel and the Nefud Desert in northern Saudi Arabia, and as far east as the Zagros Mountains of western Iran. Although records of Croctua are known from the Siwalik Hills of the northern Indian subcontinent dating to the Early Pleistocene, only a few records of Crocuta have been reported probably dating from the Late Pleistocene in the Indian subcontinent, including from Billasurgam Caves and Kurnool Caves in Andhra Pradesh, and from Tamil Nadu.Lydekker, R. (1892). The fauna of the Karnul caves. Palaeontologia Indica, 10, 23 – 58.Prasad, K. N. (1996). Pleistocene cave fauna from peninsular India. Journal of Caves and Karst Studies, 58, 30 – 34.Rao, C. R. N. (1932). On a new fossil hyaena. The Half-Yearly Journal of the Mysore University, 6, 99 –103. The northernmost records of cave hyenas 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.
Ecology
Habitat Much like African spotted hyenas, they were believed to have lived in clans based on fossils found within caves. Isotopic analysis further support this due to the clusters of isotopic values and limited variation among individuals, in addition to consumption of medium to large sized herbivores. However, because the shape of brain cavity indicates that the front part of the brain of cave hyenas was smaller than that of living spotted hyenas and more similar to that of non-social hyenas, some researchers have hypothesized that cave hyenas were less social than living spotted hyenas.
While "cave hyenas" did use caves, they were not confined to them,Diedrich, C. 2010. "Specialized horse killers in Europe – foetal horse remains in the Late Pleistocene Srbsko Chlum-Komín Cave hyena den in the Bohemian Karst (Czech Republic) and actualistic comparisons to modern African spotted hyenas as zebra hunters." Quaternary International, vol. 220, no. 1-2, pp. 174-187. being present where caves were absent, and where present only using caves intermittently, with some examples of open-air dens having been found in the fossil record, such as at Bottrop in Germany. The habitat of cave hyenas was highly variable, spanning from frigid steppe-tundra, to tropical savannah.
Diet The cave hyena's diet probably differed little from contemporary African spotted hyenas, and like living spotted hyenas, cave hyenas probably lived in groups (which in living spotted hyenas are called "clans") and were active predators rather than purely scavengers (with hunting being predominant over scavenging in the living spotted hyena). The bones of cave hyena prey were often cracked open/crushed in order to feed on the interior marrow, as is done by living spotted hyenas. Dental microwear indicates both adult and juvenile cave hyenas consumed copious amounts of bones.
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 (or alternatively generally only targeted when weak), with their young perhaps sometimes being targeted for active hunting.
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).Diedrich, C.G. & ŽÁK, K. 2006. Prey deposits and den sites of the Upper Pleistocene hyena Crocuta crocuta spelaea (Goldfuss, 1823) in horizontal and vertical caves of the Bohemian Karst (Czech Republic). Bulletin of Geosciences 81(4), 237–276 (25 figures). Czech Geological Survey, Prague. ISSN 1214-1119. 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 Perspektywiczna Cave in Poland, the assemblage is dominated by reindeer, with other remains present including bovids, equines, woolly rhinoceros and woolly mammoth. In Prolom 2 grotto in Crimea, the assemblage is dominated by saiga antelope, along with a smaller amount of wild horse, European wild ass and steppe bison. An assemblage of wild horse, steppe bison, elk and probably scavenged woolly rhinoceros, along with a small amount of long-tailed goral, moose, wild boar and Siberian musk deer, is known from the Geographical Society cave in Primorsky Krai in the Russian Far East. In Bukhtarminskaya Cave in Eastern Kazakhstan, the assemblage consists of wild horse, red deer, Siberian roe deer, and the large camel Camelus knoblochi, with additional fragmentary remains of woolly mammoth and woolly rhinoceros.
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 northern 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. At the Boh Dambang cave site in Cambodia, the assemblage includes wild boar, gaur, water buffalo, serow, sambar deer, Eld's deer, southern red muntjac and indeterminate rhinoceroses.
Competition Pathological evidence suggests much like spotted hyenas, during intraspecific conflicts, cave hyenas focused on the hind limbs. Cave hyenas also appear to have extensively engaged in cannibalism, demonstrated as numerous sites.