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Bear and bigcats anatomy
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BTW why this image is not visible in my earlier post ?.... If i go to edit page it look fine.
 *This image is copyright of its original author Anyway From data bears meat diet varies from 3% to 85% (Kitchen scrap and cattle theft etc).So,bears can sustain without meat also. Monkeys,Dogs and Boars are also omnivorous but they don't store FAT and slept (hibernation) four months in a year.So,Bears living in cold regions (bodies) are evolved to store FAT.These cute,fatty,insect and fruit eating bears are not predators especially hibernating bears.Period. 
Being an omnivore is a powerful survival trait. In some locations, a grizzly is almost completely vegetarian while in other grizzly populations, the bears eats lots of meat. In the Himalayan mountains, the Himalayan brown bear, also called the "red bear" is almost completely vegetarian while the Tibetan brown bear, also called the "blue bear" is highly carnivorous when the opportunity presents itself. Basically, a grizzly is an opportunistic forager. As for hunting, within the same location, such as Yellowstone, where one grizzly might be an accomplished hunter of elk, another grizzly hasn't the foggiest idea of how to go about it. Bears are highly individualistic.
http://www.hdw-inc.com/historycultureofwildcats.htm
How have cats survived so long?? The answer lies in the fact that there is virtually only one mainstay of the cat's diet…and that is meat. Fresh meat killed by their mother or themselves is the only item on the feline diet, and that means survival for them is no easy matter. Their food is not found on trees, waiting to be eaten. Nature has supplied the cat with the intelligence, courage, and speed to become and to stay the fabulous hunter that it needs to be to survive. Hunting preoccupies a cat almost from birth. When one observes young kittens playing, they are play-acting hunting. The process of hunting means more than the food victory of the hunt, because a cat can hunt without eating, but cannot eat without hunting. It is now thought that because the diet of the cat has remained the same for eons of time, this may explain why the thirty two species of the family of cats resemble each other so closely, with the exception of their size and the traits necessary for appropriate camouflage. Cats have had no reason to change! Excellent hunters since the lynx-like "Ur-cat" of the Miocene from whom the modern cats descend, the cats have had no need to adjust their bodies or their diets in response to major changes in the world's climate. This is because the diets of the cats didn't change. To a cat, a fish who eats algae, a bird who eats berries, and a giraffe who eats acacias are all meat for the hunting. So, while the glaciers came and went, while the vegetarians struggled to try to digest new plants and adapt themselves to overwhelming global changes, the cats simply kept on hunting, waiting to pounce on whatever managed to survive into the next epoch. It is the same limber body of the cat that hunted successfully in the Pliocene that hunts successfully today. Because eating meat is so vital to the cat's survival, being a carnavore has contributed greatly to the evolution of the cat's physical appearance and personality. The cat since ancient times has had dagger-like eyeteeth for fastening firmly onto prey, and strong, triangular cheek teeth which are capable of severing the victim's spine and shearing the flesh into bite-sized chunks that the cat can swallow. Meat-eating has also caused the cat to have a short intestinal tract, since meat is easy to digest and doesn't require a long, heavy gut (which would only weigh the cat down, slowing his ability to pounce and preventing him from hunting as effectively). Meat-eating also explains the short digestive period, the rapid passage of food through the cat, and the nutritional residue in a cat's feces. This is a main reason why cats are so concerned with burying their feces, and they never mark with feces at home, only with sprays of urine.  (11-27-2016, 08:53 PM)Polar Wrote: @parvez said, "But if pushed to limits, they seem to gasp heavily."I have not seen a living creature gasping that heavily after a brief fight. Btw you told you will post videos about bears fighting for longer periods without getting tired out as in the video i posted. Can you share? (11-27-2016, 08:52 PM)brotherbear Wrote: Parvez says: The bears must have got intimidated by the big cats. They understood that they cannot continue being carnivores (as cats have started to be dominant) or being scavengers of other's kills. Everything against bears is ridiculous to you. What more can i say? Answer me the question. Why did the bear on left in the video i posted gasped so heavily after a brief fight. Can you show an animal that gasped that much and felt so helpless after a brief fight with their own species animals. I have seen animals tiring out, but this different. They are gasping, simply they lost energy to continue to fight effectively. Atleast, huge canids in groups those times must have intimidated them. Felines or canids, either of them must have intimidated the bears. But i am sure they must have got intimidated.
Parvez, bears did not become omnivores 20 million years ago because of any predator. Being an omnivore is simply a survival strategy probably brought on according to food availability. Do you believe that every omnivore on earth chose this lifestyle out of fear of some predator? Your theory is - as I said earlier - totally ridiculous. Before you go on with this radical spam, show us some scientific documentation showing these findings.
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Post #30: The evolution of bears begins in the early Miocene era, approximately 20 mya (million years ago), when the first bear type animal named Ursavus elmensis evolved from a dog-like ancestor (Hitchcock, 2004). Fossil records from U. elmensis show carnassial teeth with larger molars for more chewing area, a trait common to present day bears.
The teeth of the 20-million-year-old Ursavus elmensis were those of an omnivore. And no; if you wish to post here at Wildfact that bears were forced to become omnivores due to fear of some other predator - then either show us your scientific evidence - or end of topic. (11-28-2016, 06:17 PM)brotherbear Wrote: Post #30: The evolution of bears begins in the early Miocene era, approximately 20 mya (million years ago), when the first bear type animal named Ursavus elmensis evolved from a dog-like ancestor (Hitchcock, 2004). Fossil records from U. elmensis show carnassial teeth with larger molars for more chewing area, a trait common to present day bears. Don't you read my posts before replying? I have long back accepted that it is my mistake. Why do you repeatedly quote that post no. 31? You did not answer to my question. Why did bear gasp so heavily after a brief fight with smaller bear in the video i posted.
A good article about fast twitching, slow twitching muscle fibres, as this topic is on cats, i will post about cats and bear related.
http://neurosoma.com/primate-muscles-eit...ow-twitch/ Other members of the animal kingdom can have muscles that are all or almost all slow or fast-twitch fiber. For example, a chicken’s breast is all fast-twitch, which is why it is white in color, and a cat’s soleus muscle is mostly long-enduring slow-twitch fibers, allowing the cat to creep in stealth mode without fatiguing. When it comes time to pounce, cats use their gastrocnemius, which is almost all anaerobic fast-twitch fibers producing massive amounts of pyruvic acid, along with a few aerobic fast-twitch fibers to process the pyruvic acid. Cats can creep, pounce, and leap 10 times their height because both their nervous system and their skeletal muscle are different from ours. We primates tend to wear out rapidly when we slink around in stealth mode because all our muscles are about 50% fast-twitch, which exhaust rapidly. Confusion also exists as to whether or not the different types of skeletal muscle fiber use different blood and nerve supply; but because fast-twitch is dependent upon slow-twitch for its metabolism, the 2 types of fiber must co-exist side by side. And because they are intermingled and interface one with another, they live within the same fascicles (bundles of muscle fiber), which means they share the same corridors between their fascicles; therefore they must share and utilize the same nerve and blood supply. However the slow-twitch fiber uses the blood supply differently because its metabolism is aerobic; more capillaries cluster around the slow-twitch fiber, making more blood available to the slow-twitch fiber in order to deliver more oxygen to its aerobic powerhouse mitochondria. Small slow-twitch fibers are ½ to ⅓ the size of fast-twitch fibers and have weaker contractions, but they have longer endurance. They carry energy with adenosine: ADP coming to the mitochondria to be oxidized to ATP, and ATP traveling back into the interior of the cell with its energy. Slow-twitch also contain large amounts of myoglobin, an iron-containing protein similar to hemoglobin in red blood cells. Myoglobin combines with oxygen and stores it until needed, then engages in its principal function of speedily transporting oxygen to the aerobic mitochondria energy factories. It is iron-carrying myoglobin that gives slow-twitch muscle fibers their red color. While slow-twitch fibers make fewer contractions per second, they are able to adapt rapidly to changes in their environment, and therefore don’t react to nerve potentials not sustained for a certain period of time. As an example, in an electrical power system, a 20-amp slow-blow fuse can temporarily take “transients” or sudden pulses of voltage over 20 amps without blowing. That sudden spike would blow an ordinary 20-amp fuse, but a slow-blow fuse will adjust to that sudden transient spike – even one of 50 amps – providing the spike doesn’t last very long. In order for a 50-amp transient to heat the element enough to blow a 20-amp slow-blow fuse, it must sustain for a period of time. Large Fast-twitch fibers twitch 3 times faster, and are 2 to 3 times larger than slow-twitch fibers; this extra size gives them greater strength of contractions, but because they use no oxygen and twitch faster, they exhaust rapidly. Fast-twitch fibers carry energy with creatine phosphate. There is no myoglobin in fast-twitch fibers, but they do store glycogen (starch) throughout their interior for energy. Remember that the body’s sugar – glucose – is stored as glycogen in both the liver and muscles until it is needed. Although fast-twitch fibers twitch faster and exhaust faster than slow-twitch fibers, they adapt more slowly than slow-twitch fibers; it takes a high number of nerve pulses per second to trigger them. Although they squeeze more contractions into less time, they are slower to adapt to changes in their environment and will fire with short spikes of stimulation. This is important because it is what allows NeuroSoma to stimulate the flower spray nerve endings coming from the fast-twitch intrafusal chain fibers within the muscle spindle, while slipping under (not firing) the annulospiral nerve endings coming from the slow-twitch intrafusal bag fibers. This difference in adaptation rate is our ‘in’, and is why we can avoid activating the stretch reflex mechanism by stroking across the grain of muscle fibers.
From this it is very clear that bear's stamina may be because of slow twitch muscle fibres, where as it's massive blow is because of fast twitching muscle fibres. But while biting which muscle fibres come into action i do not know. I suppose fast twitch muscle fibres.
Parvez, you asked the question ( post #37 ): But do you have proof bears were omnivores since 20mya?
And I answered you in post #38. (11-28-2016, 06:43 PM)brotherbear Wrote: Parvez, you asked the question ( post #37 ): But do you have proof bears were omnivores since 20mya? Do you mean they originated as omnivores from dog like ancestors? Before post 37 itself i accepted my mistake, atleast sloth bear must have just got intimidated (not that they became omnivorous due to them) by bigger big cats in India. May be not all bears. Period  *This image is copyright of its original author  *This image is copyright of its original author Distribution of red(slow twitch) and white(fast twitch) muscle fibres in bear, In case of cat,  *This image is copyright of its original author Sources: http://www.dragoart.com/tuts/21615/1/1/bear-anatomy-drawing.htm http://www.dragoart.com/tuts/20910/1/1/cat-anatomy-drawing.htm  (11-28-2016, 06:42 PM)parvez Wrote: From this it is very clear that bear's stamina may be because of slow twitch muscle fibres, where as it's massive blow is because of fast twitching muscle fibres. But while biting which muscle fibres come into action i do not know. I suppose fast twitch muscle fibres. This isn't how muscles work in general. A creature can not just choose which muscle fiber types to activate and which to not. Bears (just like big cats and about any other animal) have both a mixture of fast-twitch and slow-twitch fibers, not to mention the differing sub-fiber types within both fast-twitch and slow-twitch categorization. Yes, big cats simply have more fast-twitch fibers (and in the right places too), which explains why they are able to make more explosive movements such as accelerating whilst running, jumping distances, and reflexes (although that can be neuro-muscular coordination). However, both bears and big cats seem to have an equal explosive force output in terms of grappling and shoving (bear actually has a slight advantage here). As for stamina, bears have an advantage here due to the things you mentioned, but there are numerous accounts of big cats fighting prey/predators for an extended period of time: same with bears themselves. |
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