Pleistocene sloth bear - Melursus theobaldi

[brobear]

Unlocking the mystery of sloth bear evolution - braincatalogue.org/Sloth_bear

Sloth Bear (Melursus ursinus)

Initially thought to be related to the South American sloths, Shaw and Nodder in 1791 called the species Bradypus ursinus, noting that it was bear-like, but giving weight to the long claws and the absence of upper middle incisors. Meyer (1793) identified it as a bear and called it Melursus lybius, and in 1817, de Blainville called it Ursus labiatus because of the long lips. Iliger called it Prochilus hirsutus, the Greek genus name indicating long lips, while the specific name noted its long and coarse hair. Fischer called it Chondrorhynchus hirsutus, while Tiedemann called it Ursus longirostris.

Sloth bears may have reached their current form in the early Pleistocene, the time when the bear family specialized and dispersed. A fragment of fossilized humerus from the Pleistocene, found in Andhra Pradesh's Kurnool Basin is identical to the modern sloth bears. The fossilized skulls of a bear once named Melursus theobaldi found in the Shivaliks from the early Pleistocene or early Pliocene are thought by certain authors to represent an intermediate stage between sloth bears and ancestral brown bears. M. theobaldi itself had teeth intermediate in size between sloth bears and other bear species, though its palate was the same size as the former species, leading to the theory that it is the sloth bear's direct ancestor. Sloth bears probably arose during the mid-Pliocene and evolved in the Indian Subcontinent. The sloth bear bears evidence of having undergone a convergent evolution similar to that of other ant-eating mammals.

[brobear]

I believe that the sloth bear can thank his early ancestor, the grizzly, for his habit of fight rather than scurry up a tree. It is thought that the first grizzlies which appeared in China roughly a million years ago, some spread down into India where they evolved into sloth bears.
A strange mystery... the sloth bear and the Asiatic elephant simply don't like each other. Why?
Same seems to hold true with sun bear and orangutan in Sumatra. Why?

[Polar]

Those Chinese grizzlies could go up to a ton in weight too!

[brobear]

palaeopedia.tumblr.com/page/116

The sloth bear, Melursus ursinus (1791)

Phylum : Chordata
Class : Mammalia
Order : Carnivora
Family : Ursidae
Genus : Melursus
Species : M. ursinus
Subspecies : M.u. inornatus, M.u. ursinus

Late Pliocene/Recent (Vulnerable)
1,9 m long and 190 kg (size)
India (map)
Sloth bears may have reached their current form in the early Pleistocene, the time when the bear family specialized and dispersed. A fragment of fossilized humerus from the Pleistocene, found in Andhra Pradesh’s Kurnool Basin is identical to the modern sloth bear’s. The fossilized skulls of a bear once named Melursus theobaldi found in the Shivaliks from the early Pleistocene or early Pliocene are thought by certain authors to represent an intermediate stage between sloth bears and ancestral brown bears. M. theobaldi itself had teeth intermediate in size between sloth bears and other bear species, though its palate was the same size as the former species, leading to the theory that it is the sloth bear’s direct ancestor. Sloth bears probably arose during the mid-Pliocene and evolved in the Indian subcontinent. The sloth bear bears evidence of having undergone a convergent evolution similar to that of other ant-eating mammals.

Adult sloth bears may travel in pairs, with the males being gentle with cubs. They may fight for food. They walk in a slow, shambling motion, with their feet being set down in a noisy, flapping motion. They are capable of galloping faster than running humans. Although they appear slow and clumsy, sloth bears are excellent climbers. They climb to feed and rest, though not to escape enemies, as they prefer to stand their ground. They are capable of climbing on smooth surfaces and hang upside down like sloths. They are good swimmers, and primarily enter water to play. To mark their territory, sloth bears will scrape trees with their forepaws, and rub against them with their flanks. Sloth bears have a great vocal range. Gary Brown, in his Great Bear Almanac lists over 25 different sounds in 16 different contexts. Sounds such as barks, screams, grunts, roars, snarls, whickers, woofs and yelps are made when angered, threatening or when fighting. When hurt or afraid, they shriek, yowl or whimper. When feeding, sloth bears make loud huffing and sucking noises, which can be heard over 100 metres away. Sounds such as gurgling or humming are made by bears resting or sucking their paws. Sows will emit crooning sounds to their cubs. The species is the most vociferous when mating, and make loud, melodious calls when doing so. Sloth bears do not hibernate. They make their day beds out of broken branches in trees, and will rest in caves during the wet season. Sloth bears are the most nocturnal of bears, though sows become more active in daytime when with cubs.

sloth bears are expert hunters of termites, which they locate by smell. On arriving at a mound, they scrape at the structure with their claws till they reach the large combs at the bottom of the galleries, and will disperse the dirt with violent puffs. The termites are then sucked up through the muzzle, producing a hoovering sound which can be heard 180 meters away. Their sense of smell is strong enough to detect grubs three feet below ground. Unlike other bears, they do not congregate in feeding groups. They rarely prey on other mammals. Sloth bears may supplement their diet with fruit and plant matter: in March and April, they will eat the fallen petals of mowha trees and are partial to mangoes, sugar cane, the pods of the Golden Shower Tree and the fruit of the jack-tree. Sloth bears are extremely fond of honey. When feeding their cubs, sows are reported to regurgitate a mixture of half digested jack fruit, wood apples and pieces of honey comb. This sticky substance hardens into a dark yellow circular bread-like mass which is fed to the cubs. This “bear’s bread” is considered a delicacy by some of India’s natives.

[brobear]

Sept 4, 2018 19:56:21 GMT -5 Polar said:

Those Chinese grizzlies could go up to a ton in weight too!

Polar - IF you can find any info on the Chinese grizzly, please post it on the topic Pleistocene Grizzly. I have searched and come up empty. -Thank you. 

[brobear]

shaggygod.proboards.com/thread/143/sloth-bear-profile  
 
Evolutionary history

The sloth bear may have existed in its present form from the beginning of the Pleistocene Epoch (Erdbrink 1953), a period when the bears speciated and dispersed (Kurten 1968, Talbot and Shields 1996). A fossilised fragment of a humerus bone from the Pleistocene was found in the Kurnool basin of Andhra Pradesh and it is identical to modern specimens. According to Erdbrink (1953), it is not clear if the fossilised cranium from the early Pleistocene or late Pliocene found in the Shivaliks, is an intermediate stage between the sloth bear and the ancestor of the brown bear (Ursus arctos). This fossil, named Melursus theobaldi by earlier workers, has teeth of intermediate size between M. ursinus and other bears. However, because this fossil has a palate of the same peculiar form as present day sloth bear, Erdbrink believed that M. theobaldi is clearly a direct ancestor of the sloth bear. 
 
The sloth bear probably radiated from the ancestral stalk of ursids during the mid-Pliocene (Erdbrink 1953, Kurten 1968, Goldman et al. 1989, Talbot and Shields 1996) and evolved within the subtropical region, developing several morphological characteristics suited to its feeding niche and its habitat. Several features of the sloth bear appear to be concordant with the convergent evolution in other mammalian anteaters (Redford 1987, Joshi et al. 1999), including low reproductive rate, solitary habits, extended parental care, extensive carrying of young by the mother, and a low basal metabolic rate (McNab 1992). However, the low reproductive rate, solitary habits and extended parental care are features of the Ursidae in general. The basal metabolic rate of sloth bear too is similar to the omnivorous American black bear (Ursus americanus) (McNab 1992). Thus, it appears that the only feature that distinguishes the sloth bear from other omnivorous bears is the carrying of the young. This feature, however, is more likely to have been evolved because of predation pressure in the sloth bear habitat rather than myrmecophagy (Joshi et al. 1999).

[brobear]

animals.fandom.com/wiki/Sloth_Bear 
 
Sloth bears may have reached their current form in the early Pleistocene, the time when the bear family specialized and dispersed. A fragment of fossilized humerus from the Pleistocene, found in Andhra Pradesh's Kurnool Basin is identical to the modern sloth bears. The fossilized skulls of a bear once named Melursus theobaldi found in the Shivaliks from the early Pleistocene or early Pliocene are thought by certain authors to represent an intermediate stage between sloth bears and ancestral brown bears. M. theobaldi itself had teeth intermediate in size between sloth bears and other bear species, though its palate was the same size as the former species, leading to the theory that it is the sloth bear's direct ancestor. Sloth bears probably arose during the mid-Pliocene and evolved in the Indian Subcontinent. The sloth bear bears evidence of having undergone a convergent evolution similar to that of other ant-eating mammals.

[brobear]

animals.fandom.com/wiki/Sloth_Bear

Initially thought to be related to the South American sloths, Shaw and Nodder in 1791 called the species Bradypus ursinus, noting that it was bear-like, but giving weight to the long claws and the absence of upper middle incisors. Meyer (1793) identified it as a bear and called it Melursus lybius, and in 1817, de Blainville called it Ursus labiatus because of the long lips. Iliger called it Prochilus hirsutus, the Greek genus name indicating long lips, while the specific name noted its long and coarse hair. Fischer called it Chondrorhynchus hirsutus, while Tiedemann called it Ursus longirostris.

Sloth bears may have reached their current form in the early Pleistocene, the time when the bear family specialized and dispersed. A fragment of fossilized humerus from the Pleistocene, found in Andhra Pradesh's Kurnool Basin is identical to the modern sloth bears. The fossilized skulls of a bear once named Melursus theobaldi found in the Shivaliks from the early Pleistocene or early Pliocene are thought by certain authors to represent an intermediate stage between sloth bears and ancestral brown bears. M. theobaldi itself had teeth intermediate in size between sloth bears and other bear species, though its palate was the same size as the former species, leading to the theory that it is the sloth bear's direct ancestor. Sloth bears probably arose during the mid-Pliocene and evolved in the Indian Subcontinent. The sloth bear bears evidence of having undergone a convergent evolution similar to that of other ant-eating mammals.

[brobear]

en.wikipedia.org/wiki/Ursinae

Ursinae is a subfamily of Ursidae (bears) named by Swainson (1835) though probably named before Hunt 1998. It was assigned to Ursidae by Bjork (1970), Hunt (1998) and Jin et al. (2007). The genera Melursus and Helarctos are sometimes also included in Ursus. The Asiatic black bear and the polar bear used to be placed in their own genera, Selenarctos and Thalarctos; these are now placed at subgenus rank.

[OldGreenGrolar]

Sept 29, 2018 7:52:54 GMT -5 brobear said:

Sept 4, 2018 19:56:21 GMT -5 Polar said:

Those Chinese grizzlies could go up to a ton in weight too!

Polar - IF you can find any info on the Chinese grizzly, please post it on the topic Pleistocene Grizzly. I have searched and come up empty. -Thank you. 

These Chinese grizzlies are probably Pleistocene Ussuri brown bears.

[brobear]

Jan 5, 2020 7:15:21 GMT -5 brobear said:

animals.fandom.com/wiki/Sloth_Bear 
 
Sloth bears may have reached their current form in the early Pleistocene, the time when the bear family specialized and dispersed. A fragment of fossilized humerus from the Pleistocene, found in Andhra Pradesh's Kurnool Basin is identical to the modern sloth bears. The fossilized skulls of a bear once named Melursus theobaldi found in the Shivaliks from the early Pleistocene or early Pliocene are thought by certain authors to represent an intermediate stage between sloth bears and ancestral brown bears. M. theobaldi itself had teeth intermediate in size between sloth bears and other bear species, though its palate was the same size as the former species, leading to the theory that it is the sloth bear's direct ancestor. Sloth bears probably arose during the mid-Pliocene and evolved in the Indian Subcontinent. The sloth bear bears evidence of having undergone a convergent evolution similar to that of other ant-eating mammals.

We are told of Melursus theobaldi, the ancestral sloth bear. but told what? Nothing.

[OldGreenGrolar]

Lets hope there will be more information soon.