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The American black bear (Ursus americanus) is a medium-sized bear native to North America. It is the continent's smallest and most widely distributed bear species. American black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in search of food. Sometimes they become attracted to human communities because of the immediate availability of food. The American black bear is the world's most common bear species.
It is listed by the International Union for Conservation of Nature (IUCN) as a least-concern species, due to its widespread distribution and a large population estimated to be twice that of all other bear species combined. Along with the brown bear, it is one of only two of the eight modern bear species not considered by the IUCN to be globally threatened with extinction. American black bears often mark trees using their teeth and claws as a form of communication with other bears, a behavior common to many species of bears.
Despite living in North America, American black bears are not closely related to brown bears and polar bears; genetic studies reveal that they split from a common ancestor 5.05 million years ago (mya). American and Asian black bears are considered sister taxa and are more closely related to each other than to the other modern species of bears. According to recent studies, the sun bear is also a relatively recent split from this lineage.
A small primitive bear called Ursus abstrusus is the oldest known North American fossil member of the genus Ursus, dated to 4.95 mya. This suggests that U. abstrusus may be the direct ancestor of the American black bear, which evolved in North America. Although Wolverton and Lyman still consider U. vitabilis an "apparent precursor to modern black bears", it has also been placed within U. americanus.
The ancestors of American black bears and Asian black bears diverged from sun bears 4.58 mya. The American black bear then split from the Asian black bear 4.08 mya. The earliest American black bear fossils, which were located in Port Kennedy, Pennsylvania, greatly resemble the Asian species, though later specimens grew to sizes comparable to grizzly bears. From the Holocene to the present, American black bears seem to have shrunk in size, but this has been disputed because of problems with dating these fossil specimens.
The American black bear lived during the same period as the giant and lesser short-faced bears (Arctodus simus and A. pristinus, respectively) and the Florida spectacled bear (Tremarctos floridanus). These tremarctine bears evolved from bears that had emigrated from Asia to North America 7–8 ma. The giant and lesser short-faced bears are thought to have been heavily carnivorous and the Florida spectacled bear more herbivorous, while the American black bears remained arboreal omnivores, like their Asian ancestors.
The American black bear's generalist behavior allowed it to exploit a wider variety of foods and has been given as a reason why, of these three genera, it alone survived climate and vegetative changes through the last Ice Age while the other, more specialized North American predators became extinct. However, both Arctodus and Tremarctos had survived several other, previous ice ages. After these prehistoric ursids became extinct during the last glacial period 10,000 years ago, American black bears were probably the only bear present in much of North America until the migration of brown bears to the rest of the continent.
Build
Some specimens may develop a white "crescent moon" blaze on the chest. This white blaze, which is constant in Asian black bears, occurs in only 25% of American black bears.
Skull
The skulls of American black bears are broad, with narrow muzzles and large jaw hinges. In Virginia, the total length of adult bear skulls was found to average 262 to 317 mm (10.3 to 12.5 in). Across its range, the greatest skull length for the species has been reportedly measured from 23.5 to 35 cm (9.3 to 13.8 in). Females tend to have slenderer and more pointed faces than males. Their claws are typically black or grayish-brown.
The claws are short and rounded, being thick at the base and tapering to a point. Claws from both hind and front legs are almost identical in length, though the foreclaws tend to be more sharply curved. The paws of the species are relatively large, with a rear foot length of 13.7 to 22.5 cm (5.4 to 8.9 in), which is proportionately larger than other medium-sized bear species, but much smaller than the paws of large adult brown, and especially polar, bears. The soles of the feet are black or brownish and are naked, leathery and deeply wrinkled. The hind legs are relatively longer than those of Asian black bears. The vestigial tail is usually 4.8 inches (120 mm) long. The ears are small and rounded and are set well back on the head.
American black bears are highly dexterous, being capable of opening screw-top jars and manipulating door latches. They also have great physical strength. They have been known to turn over flat-shaped rocks weighing 310 to 325 pounds (141 to 147 kg) by flipping them over with a single foreleg. They move in a rhythmic, sure-footed way and can run at speeds of 25 to 30 miles per hour (40 to 48 km/h). American black bears have good eyesight and have been proven experimentally to be able to learn visual color discrimination tasks faster than chimpanzees and just as fast as domestic dogs. They are also capable of rapidly learning to distinguish different shapes such as small triangles, circles and squares
I hope you liked this post and as always have a chilled day from the viking.
AMERICAN BLACK BEAR
The American black bear (Ursus americanus) is a medium-sized bear native to North America. It is the continent's smallest and most widely distributed bear species. American black bears are omnivores, with their diets varying greatly depending on season and location. They typically live in largely forested areas, but do leave forests in search of food. Sometimes they become attracted to human communities because of the immediate availability of food. The American black bear is the world's most common bear species.
It is listed by the International Union for Conservation of Nature (IUCN) as a least-concern species, due to its widespread distribution and a large population estimated to be twice that of all other bear species combined. Along with the brown bear, it is one of only two of the eight modern bear species not considered by the IUCN to be globally threatened with extinction. American black bears often mark trees using their teeth and claws as a form of communication with other bears, a behavior common to many species of bears.
Despite living in North America, American black bears are not closely related to brown bears and polar bears; genetic studies reveal that they split from a common ancestor 5.05 million years ago (mya). American and Asian black bears are considered sister taxa and are more closely related to each other than to the other modern species of bears. According to recent studies, the sun bear is also a relatively recent split from this lineage.
A small primitive bear called Ursus abstrusus is the oldest known North American fossil member of the genus Ursus, dated to 4.95 mya. This suggests that U. abstrusus may be the direct ancestor of the American black bear, which evolved in North America. Although Wolverton and Lyman still consider U. vitabilis an "apparent precursor to modern black bears", it has also been placed within U. americanus.
The ancestors of American black bears and Asian black bears diverged from sun bears 4.58 mya. The American black bear then split from the Asian black bear 4.08 mya. The earliest American black bear fossils, which were located in Port Kennedy, Pennsylvania, greatly resemble the Asian species, though later specimens grew to sizes comparable to grizzly bears. From the Holocene to the present, American black bears seem to have shrunk in size, but this has been disputed because of problems with dating these fossil specimens.
The American black bear lived during the same period as the giant and lesser short-faced bears (Arctodus simus and A. pristinus, respectively) and the Florida spectacled bear (Tremarctos floridanus). These tremarctine bears evolved from bears that had emigrated from Asia to North America 7–8 ma. The giant and lesser short-faced bears are thought to have been heavily carnivorous and the Florida spectacled bear more herbivorous, while the American black bears remained arboreal omnivores, like their Asian ancestors.
The American black bear's generalist behavior allowed it to exploit a wider variety of foods and has been given as a reason why, of these three genera, it alone survived climate and vegetative changes through the last Ice Age while the other, more specialized North American predators became extinct. However, both Arctodus and Tremarctos had survived several other, previous ice ages. After these prehistoric ursids became extinct during the last glacial period 10,000 years ago, American black bears were probably the only bear present in much of North America until the migration of brown bears to the rest of the continent.
Build
Some specimens may develop a white "crescent moon" blaze on the chest. This white blaze, which is constant in Asian black bears, occurs in only 25% of American black bears.
Skull
The skulls of American black bears are broad, with narrow muzzles and large jaw hinges. In Virginia, the total length of adult bear skulls was found to average 262 to 317 mm (10.3 to 12.5 in). Across its range, the greatest skull length for the species has been reportedly measured from 23.5 to 35 cm (9.3 to 13.8 in). Females tend to have slenderer and more pointed faces than males. Their claws are typically black or grayish-brown.
The claws are short and rounded, being thick at the base and tapering to a point. Claws from both hind and front legs are almost identical in length, though the foreclaws tend to be more sharply curved. The paws of the species are relatively large, with a rear foot length of 13.7 to 22.5 cm (5.4 to 8.9 in), which is proportionately larger than other medium-sized bear species, but much smaller than the paws of large adult brown, and especially polar, bears. The soles of the feet are black or brownish and are naked, leathery and deeply wrinkled. The hind legs are relatively longer than those of Asian black bears. The vestigial tail is usually 4.8 inches (120 mm) long. The ears are small and rounded and are set well back on the head.
American black bears are highly dexterous, being capable of opening screw-top jars and manipulating door latches. They also have great physical strength. They have been known to turn over flat-shaped rocks weighing 310 to 325 pounds (141 to 147 kg) by flipping them over with a single foreleg. They move in a rhythmic, sure-footed way and can run at speeds of 25 to 30 miles per hour (40 to 48 km/h). American black bears have good eyesight and have been proven experimentally to be able to learn visual color discrimination tasks faster than chimpanzees and just as fast as domestic dogs. They are also capable of rapidly learning to distinguish different shapes such as small triangles, circles and squares
I hope you liked this post and as always have a chilled day from the viking.
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