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(03-16-2019, 09:47 AM)Sanju Wrote: Hyena Genera are one of the most wide spread carnivores across Eurasia and Dark Continent. Different clades have different regions of origin in their respective continental ranges.
*This image is copyright of its original author
*This image is copyright of its original author
Image: A spotted hyena (Crocuta crocuta) in the January cold at Blijdorp Zoo in the Netherlands. Photo from Flickr user Silvain de Munck.
This is Giant Cave Spotted_hyena or Ice Age Hyena (C. crocuta spelaea) and lived during Middle to Late Pleistocene about 0.5–0.011 Ma. Spotted Hyena as a species had a 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. The cave hyena (Crocuta crocuta spelaea), also known as the Ice Age spotted hyena, was a paleosubspecies of spotted hyena. This is one of the widespread sprecies which ranged from the Iberian Peninsula to eastern Siberia.
It is one of the best known mammals of the Ice Age and is well represented in many European bone caves. The cave hyena was a highly specialised animal, with its progressive and regressive features being more developed than in its modern African relative. The cause of the cave hyena's extinction is not fully understood, though it could have been due to a combination of factors, including climate change and competition with other predators like the Panthera tigris acutidens or Wanhsien Tiger.
Another spotted Hyena considered species Crocuta sivalensis [Discovered by Kurtén, Björn (1968) "Pleistocene mammals of Europe"].
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Lars Werdelin and Margaret E. Lewis "The Taxonomic Identity of the Type Specimen of Crocuta sivalensis (Falconer, 1867)," Journal of Vertebrate Paleontology 32(6), (1 November 2012). Both Björn Kurtén and Camille Arambourg promoted an Asiatic origin for the species; Kurtén focussed his arguments on the Plio-PleistocenetaxonCrocuta 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 deposists dating from the early Pleistocene, a similar age to the Asian C. sivalensis.
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 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.
Its appearance in Europe and China during the Cromerian period 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.
The earliest migration of spotted hyenas from Africa to Eurasia began less than 3.5 million years ago, most probably from the area where the first spotted hyena fossils were discovered, reaching East Asia and most likely also Pakistan.
The second migration of spotted hyenas occurred less than 1.3–1.5 million years ago and resulted in the first arrival of hyenas in Europe and a separation of African spotted hyenas into a southern and a northern population.
The third spotted hyena migration took place 0.36 million years ago, starting from the northern African population and reaching both Europe and Asia. Unlike other African carnivores, with the exception of the leopard, there is no evidence to suggest that spotted hyenas underwent a genetic bottleneck during the Pleistocene.
The ancestors of the genus Crocuta diverged from Hyaena (the genus of striped and brown hyenas) 10 million years ago.
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A restoration of Pachycrocuta brevirostris. Credit: Tiberio Wikimedia
Pachycrocuta brevirostris (Short Faced Hyena or Giant Hyena) biggest Hyena of all time known to man which was as heavy as a lion but only as tall as a modern spotted hyena lived all over Africa, Europe, and Asia during Pliocene to Pleistocene, 3 to 0.5. million years ago. There are hundreds of skeletal elements from multiple fossil sites through the Old World. It has unknown phylogenetic relationship as sometimes considered as exceptionally large sized subspecies of Brown Hyena or Striped Hyena as well as with Spotted Hyena.
It has been proposed that Pachycrocuta was outcompeted and driven to extinction by the spotted hyena, which was formerly present in Eurasia as well as Africa.
Other than these there is a probability that most recent modern Tiger (tigris tigris) subspecies Caspian Tiger/Hyrcanian tiger/Turanian tiger, South China Tiger and Siberian tiger might have coexisted with the Cave Hyena for a short time period during Late Pleistocene and Early Holocene.
*This image is copyright of its original author
*This image is copyright of its original author
Cave hyenas
The world's most recent mass extinction, which occurred between the end of the Pleistocene and the dawn of the Holocene around 12,000 years ago. This was the extinction which wiped out the mammoths, mastodons, saber-toothed cats, and giant ground sloths, but, as with any extinction, the pruning back of ancient lineages is only part of the story.
No mass extinction has ever entirely extinguished life on earth. There have always been survivors, and, thanks to the contingent nature of evolution, these were the creatures which set the stage for the succeeding radiations of life in a world stripped of its previous ecological richness. Yet species and lineages which survived mass extinction events have not always emerge unscathed. In the world's latest mass extinction, horses and camels were extirpated from the continent of their origin - North America - and predators which once prowled much of the northern hemisphere, such as lions, had their ranges severely restricted. Among tattered remnants of the Pleistocene world are spotted hyenas (Crocuta crocuta), and in a new study published in Quaternary Science Reviews scientists Sara Varela, Jorge Lobo, Jesús Rodríguez, and Persaram Batra have presented an analysis of climate's role in the disappearance of the bone-crushing mammals from the European continent.
In terms of global ecology, the waning days of the Pleistocene were marked by at least two major events. The world's vast ice sheets retreated as the global climate became warmer and wetter, and by 50,000 years ago our species had begun to spread out of Africa to continents beyond. Both events have been taken as triggers for the extinction of the world's megafauna, and both likely had an influence on populations of spotted hyenas in Europe. What Varela and colleagues wanted to find out was whether the disappearance of the European hyenas could be attributed to climate change, and, if climate was not solely responsible, what else might have pushed them over the edge.
As reviewed by the authors, spotted hyenas were present in Europe for about 1 million years and ranged from the western coast of the Iberian Peninsula to the Ural Mountains. To determine the particular climatic niche of these hyenas over the span of space and time, Varela and co-authors combined the known distribution of hyena fossils with climate data to estimate the existence of preferred hyena habitats at five time periods from 126,000 years ago to the present. During this time the earth went from interglacial to the last "ice age" and back to an interglacial again, and so the biogeography of hyenas during the waxing and waning of the glaciers has the potential to illustrate the effects of climate change on European hyenas.
As it turned out, the spotted hyena is a hardy species which was widespread during the oscillating climate shifts. Even though many of the Pleistocene hyenas endured colder and drier conditions than their living counterparts in Africa, some of the prehistoric fossil sites had conditions comparable to areas where spotted hyenas live today. Hence, it cannot be said that the European hyenas were strictly adapted to either cold or warm climates and were a victims of a change in temperature alone. Spotted hyenas were clearly capable of living in both glacial and interglacial conditions - by all accounts there should still be European hyenas - but just because hyenas survived into the height of the ice age does not mean that conditions were ideal for them.
While spotted hyenas ranged over almost the whole of Europe during much of the past 126,000 years, at the 21,000 year mark the intense cold restricted them to a band of habitats south of present-day Lithuania. In this situation, Varela and colleagues hypothesize, the hyenas could have been placed under intense climatic stress and experienced the fragmentation of their populations. This would have been a critical time for the European hyenas in which they were especially vulnerable to changes in the abundance of prey, perhaps further altered by competition with humans, but this hypothesis has yet to be examined in full detail. For now it is clear that changes in temperature and precipitation alone cannot account for the extirpation of the European hyenas, but exactly what ushered them off the evolutionary stage remains unknown.
The ultimate cause of the cave hyena's extinction is still poorly understood. While climate change has been forwarded as a possible reason, it is insufficient to explain the animal's complete extinction; although the extremely cold conditions following the Last Glacial Maximum (LGM) diminished favourable hyena habitat in Northern Europe, and separated cave hyena populations from their African kin, there were still habitable localities in Southern and Central Europe at that time, and the animal survived many other cold periods during the Pleistocene.
In the Iberian Peninsula, climate change was ruled out as the sole cause of the cave hyena's extinction, for although the LGM resulted in a mass extinction of several hyena prey species, the red deer and several other herbivore species survived and would have still have adequately sustained hyena populations.
In Western Europe at least, the cave hyena's extinction coincided with a decline in grasslands 12,500 years ago. Europe experienced a massive loss of lowland habitats favoured by cave hyenas, and a corresponding increase in mixed woodlands. Cave hyenas, under these circumstances, would have been outcompeted by wolves and humans which were as much at home in forests as in open lands, and in highlands as in lowlands. Cave hyena populations began to shrink after roughly 20,000 years ago, completely disappearing from Western Europe between 14-11,000 years ago, and earlier in some areas.
(Varela, S., Lobo, J., Rodríguez, J., & Batra, P. (2010). Were the Late Pleistocene climatic changes responsible for the disappearance of the European spotted hyena populations?)
Wow, you know a lot about both species. This information is very appreciated. I'll ask you this, do you think the social structure of Pachycrocuta was affected by the habitat like it does with wolves?
