Cave hyena

Reconstruction, Heinrichshöhle, Germany.

The main difference between the spotted hyena and the cave hyena lies in the different length of the bones of the hind and front limbs. In the cave hyena, the humerus and the femur are longer, indicating an adaptation to environments other than those of the spotted hyena. The former was also a heavier and more robust animal: an almost complete specimen, found from the Los Aprendices cave in northern Spain, was estimated to weigh 103 kilograms. As in the spotted hyena, the females were larger than the males. A study of 16 fossil specimens of Pleistocene Crocuta indicated that the cave hyena was subject to Bergmann's rule, becoming larger during glacial periods and smaller during interglacial periods. The same study revealed a progressive increase in carnivorous tooth adaptations during glacial periods, indicating that it was an even more active hunter than today's spotted hyena, a behaviour necessitated by the need to feed on calorie rich fresh meat in a freezing environment. Rock paintings in the Lascaux and Chauvet Caves indicate that the cave hyena had the characteristic patches and mane of the spotted hyena. It has been proposed that it possessed thicker fur than the spotted hyena as an environmental adaptation.

Cave hyena with cub, depicted on a Moldovan postage stamp

Cartoon by William Conybeare (1822) of Buckland discovering the Kirkdale hyena dens.

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.[4]

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.[4]

Analysis of the mitochondrial genomes of Eurasian Crocuta specimens shows no clear separation from African lineages. However, analysis of full nuclear genomes 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 Asian populations (the latter often assigned to the separate subspecies C. crocuta ultima) were distinct from each other, but were more closely related to each other overall than to African Crocuta populations.[1] 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 Asian Crocuta, suggesting gene flow between the two groups after the split between the Asian and European populations.[1]

The youngest known specimens of cave hyenas in Europe date to around 31,000 years ago,[9] while the youngest specimens in East Asia date to around 20,000 years ago.[10] Potential causal factors for extinction include decreasing temperatures, competition with other carnivores, including humans for food and living space, and decreased prey abundance.[9]

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

• Pachycrocuta

Wikimedia Commons has media related to Crocuta crocuta spelaea.

• (in French) Cuvier, Georges, Note sur les ossemens fossiles d’hyènes, Nouveau Bulletin des Sciences, Tome 1, 1807-1809 (pp. 149–150).