Short-faced bear
| Short-faced bear | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
Arctodus simus in size comparison with a human |
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| Temporal occurrence | ||||||||||||
| Pliocene to Pleistocene | ||||||||||||
| 4.9 million years to 11,000 years | ||||||||||||
| Locations | ||||||||||||
| Systematics | ||||||||||||
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| Scientific name | ||||||||||||
| Arctodus simus | ||||||||||||
| Cope , 1897 | ||||||||||||
The short- faced bear ( Arctodus simus ), also known as the giant short-snouted bear or bulldog bear , was a very large representative of the bears that lived in North America until the end of the Pleistocene , about 11,000 years ago.
anatomy
It was believed to be one of the largest predatory mammals that lived on Earth during the Ice Age. However, some early giant carnivorous mammals such as Andrewsarchus , Sarkastodon, and Megistotherium appear to have been even larger.
According to the skeleton finds, the shoulder height was around 1.5 to 1.8 meters, and when erect he reached a height of 3.40 m. It was calculated that the male specimens weighed a little over 600 kg on average, but the largest males could probably weigh up to 1000 kg, a good 200 kg heavier than the largest Kodiak bears or polar bears . As with most of today's bear species, the sexual dimorphism in terms of size and strength was very pronounced in the short-faced bears. In the Riverbluff Cave, a cave in Missouri, claw marks of a short-faced bear were found at a height of 4.57 m, which proved that this bear was at least 3.65 m tall.
In addition to the particularly short snout, from which it owes its name, its anatomy shows other peculiarities within the bear family. Of all known bears, Arctodus had the most carnivorous (meat-eating) set of teeth. His canine teeth were strong and set apart like a big cat, which, together with the enormous jaw muscles, gave him a powerful death bite. In addition, the posterior teeth were very efficient breaking scissors for cutting up meat, tendons, skin and bones. Overall, the proportions of the skull are much more similar to those of a large big cat than to a brown or black bear .
For a bear, disproportionately long limbs indicate that as a runner it must have been much faster and more persistent than today's bears, which can easily reach the speed of a galloping horse over short distances . A particularly sloping back line and two prominent shoulder bumps are reminiscent of the physique of a hyena , although its mode of locomotion and feeding as a predator and opportunistic scavenger may have been quite similar. However, one should keep in mind that today's spotted hyenas are very active and successful predators that hunt even such large and well-fortified prey as zebras , and that only carnivores living on carrion do not occur. The success of the hunt for the hyenas is due to hunting in groups. Arctodus simus , however, was likely a loner.
distribution
The short-faced bear inhabited large parts of the North American continent. In the north, the species reached Alaska, where it is known for about 27,000 year old fossils from the Ikpikpuk River. By far the most common bone finds were made in present-day California. Data collected by accelerator mass spectrometry confirm that the short- faced bear did not become extinct until the transition from the Pleistocene to the Holocene , about 11,000 radiocarbon years ago.
Way of life
With its oversized olfactory organ, it would have scented a carcass of a large mammal from the Ice Age at that time, such as the woolly mammoth , from a great distance, only to break it open with its powerful jaws, crush the bones and prefer to eat the protein-rich bone marrow . As in today's African and Asian ecosystems, however, the carcasses of such large animals with long life expectancy and low reproductive rates will only rarely have enriched the menu of the Arctodus, and the short-snouted bear also lacked the massively enlarged and high-crowned posterior teeth of the bone-crushing hyena dentition, which is why it is questionable whether he was actually able to break the bones of really large animals in the first place.
With the extinction of the other large mammals at the end of the Ice Age ( Quaternary extinction wave ), no adequate food was found for him either, and he thus went about 11,000 years BC. Towards the same end. Most likely, the short-faced bear was also an opportunistic predator that mostly hunted, and its long legs, geared towards fast running, served it well. Large herbivores such as horses , bison , camels and various species of deer were probably among its preferred prey. Even among today's grizzly bears, there are always some that often hunt larger prey. The long-legged short-faced bear, who specialized in meat, was certainly also a very good hunter, capable of overpowering very large and defensive prey. On the other hand, like most other predators, it used every opportunity to eat fresh carcasses and take prey from smaller predators. To see him as a pure scavenger is speculative.
relationship
The closest relative still alive today is the spectacled bear in South America . A related form is known from Florida , Tremarctos floridanus , which, similar to the European cave bear, apparently specialized in vegetable food and was slightly larger than the recent spectacled bear. The extinction of the short- faced bear favored its smaller and weaker relatives, the brown bears , who were now able to spread further because, on the one hand, they had less competition and, on the other hand, the large, aggressive short- nosed bears might also be hunted and eaten.
Cryptozoology
In Kamchatka , the local Koryak hunters believe in the existence of a gigantic bear, which they call Irkulyen (= holy bear) and which, according to speculations by zoologists Paul Ward and Stan Bergman, could possibly have dimensions similar to Arctodus simus . However, it is precisely from this area that the largest Eurasian brown bears are known, which are almost the size of the North American Kodiak bears , and there are no bones found from short-faced bears outside of America, which is why these are more likely to be some oversized specimens of the brown bear.
literature
- Miles Barton: Wild America. Witnesses to the Ice Age. vgs, Cologne 2003, ISBN 3-8025-1558-7 .
- Ian Stirling (Ed.): Bears. All species from the rainforest to the polar ice. Illustrated by David Kirshner and Frank Knight. Orbis-Verlag, Munich 2002, ISBN 3-572-01332-1 .
- Kenneth B. Tankersley: In Search of Ice Age Americans. Gibbs Smith, Salt Lake City UT 2002, ISBN 1-58685-021-0 .
- Blaine W. Schubert, James E. Kaufmann: A partial short-faced bear skeleton from an Ozark cave with comments on the paleobiology of the species. In: Journal of Cave and Karst Studies. Volume 65, No. 2, pp. 101-110 ( PDF; 487 kB ).
- Gary Brown: Great Bear Almanac. 1996, ISBN 1558214747 , p. 340.
- Gary Brown: The Bear Almanac, 2nd: A Comprehensive Guide to the Bears of the World. The Globe Pequot Press, 2013, ISBN 978-0762788064 , p. 8.
Web links
- Research Report on University of Arkansas Excavation ( March 20, 2008 memento on Internet Archive )
- private page Vistaverde: Brown Bear vs. Arctodus simus
supporting documents
- ↑ [1] Riverbluff Cave - The official website. June 22, 2016.
- ↑ CS Churcher, AV Morgan, LD Carter: Arctodus simus from the Alaskan Arctic Slope. In: Canadian Journal of Earth Sciences. Volume 30, No. 5, 1993 pp. 1007-1013, doi : 10.1139 / e93-084 .
- ↑ Archived copy ( memento of the original dated November 14, 2014 in the Internet Archive ) Info: The archive link was inserted automatically and has not yet been checked. Please check the original and archive link according to the instructions and then remove this notice. Datasheets, San Diego Zoo, July 2009
- ↑ Blaine W. Schubert: Late Quaternary chronology and extinction of North American giant short-faced bears (Arctodus simus). In: Quaternary International. Volume 217 No. 1-2, April 15, 2010, pp. 188-194, doi : 10.1016 / j.quaint.2009.11.010 .
