Strength and Girth Comparison of Bears and Big Cats

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Grizzly. 
             

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Locomotion (Craighead et al 1995) (Weber 1986)
Favored gait is a slow shuffle.
Undisturbed bear walks 5.5-6.0 km/hr (3.4-3.7 mi/hr)
Adult bear can gallop at over 56 km/hr (35 m/hr) for 3 km (2 mi).
Can trot with average speed of 10-12 km/hr (6.2-7.5 mi/hr)
Tree-climbing: (Wilson & Mittermeir 2009)
All juvenile Brown Bears can climb trees
Adults in North America rarely climb trees (Black Bears do climb trees)
Adult Brown Bears in Europe and Asia climb trees
Often stand while stopped
Use trails that are shortest distance between feeding and resting areas
May hesitate 20 minutes while assessing an exposed area before entering open space.
Interspecies Interaction (Murie 1985) (Podruzny et al 1999) (Mowat & Heard 2006)

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Unlike wolves and the big cats, bears are simply not popular animals. Finding data and illustrations of bear anatomy is not an easy task.
 

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The Grizzly.
 

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www.natgeotv.com/uk/casey-and-brutus-grizzly-encounters/facts

Basic Anatomy of a Grizzly Bear
Bears are among the most massive and powerful animals on earth.
The grizzly bear got its name from its grizzled fur, fur that is shiny and shimmery on the tips.
Bears can have a 1.4 metre head.
A grizzly’s mouth gape measure around 30 centimetres and holds four 5 centimetre canines.
Grizzly bears have a bite-force of over 8,000,000 pascals, enough to crush a bowling ball.
Grizzly bears have a muscular hump on the upper back, which helps differentiate them from other bears in the wild.
On all four feet, grizzly bears can stand around 100 centimetres tall at the shoulder and nearly 2 metres long.
Standing up grizzly bears can measure over 2.5 metres tall.
Grizzly bears have “dish-shaped noses” with a sense of smell seven times stronger than a bloodhound’s.
Wild grizzlies have claws up to 10 centimetres long.
The front paws of a grizzly are about 20 centimetres by 20 centimetres.
One way you can identify grizzly tracks is the straight line of their toes and big claws sticking out about 2.5 centimetres away from the toes.
A grizzly bear has to eat almost 20,000 calories a day.
Behaviour of a Grizzly Bear
Adolescent bears are known as “sub-adults” until they reach maturity.
Sub-adults are bears that have just been kicked away from mother. They could be two, three, four years old but often once they’re kicked away from mother they remain in sibling groups.
Out in the wild grizzly bears smell horrible, because they roll around in every dead thing they come across to cover up their scent, so when they’re sneaking up on prey they smell like a dead thing, not an actual bear, so things don’t fear them.
During five months of hibernation, grizzlies will lose up to 30 percent of their body weight.
'Woofing' is a sound that means the grizzly is uncomfortable.
Adult male grizzlies are not social animals. They do not like competition for food or a female’s attention.
An adult bear can reach speeds of nearly 65 kilometres per hour.
Bears cannot sustain speed over long distances because their massive muscular bodies are not built for sprinting.

[brobear]

By Grraahh - 

 
"To survive in open habitat, a mammal must be able to defend itself from predators or be fast enough to escape them. Consequently, as the body size of some bear species increased, they probably occupied more open habitat for longer periods, and were able to increase the proportion of vegetation in the diet. Their larger size also made them better able to defend themselves from predators. As the diet became progressively more vegetative, there would have been continuing pressure for body size to increase so enough vegetation could be ingested and processed to substitute for a high quality diet of animal material. Larger body size also made it possible to travel more in search of patchy food resources and to store and carry more fat with which to survive during periods of seasonal or unpredictable food shortage. With increased body size and well-developed canines, some bears were able to kill ungulates and other mammals, defend carrion from competitors, and protect themselves from other predators. Through this unique combination of being able to be predators, scavengers, and herbivores, they were able to exploit several food bases." 

 "A vegetative diet alone is not a sufficient stimulus to produce large size, as is illustrated by several successful taxa of small mammals. Small animals are more vulnerable to predation than are large ones so they need to remain adjacent to escape habitat such as holes in the ground, trees, or thick vegetation. To survive in open habitat, a mammal must be able to defend itself from predators or be fast enough to escape them. Consequently, as the body size of some bear species increased, they probably occupied more open habitat for longer periods, and were able to increase the proportion of vegetation in the diet. Their larger size also made them better able to defend themselves from predators. As the diet became progressively more vegetative, there would have been continuing pressure for body size to increase so enough vegetation could be ingested and processed to substitute for a high quality diet of animal material. Larger body size also made it possible to travel more in search of patchy food resources and to store and carry more fat with which to survive during periods of seasonal or unpredictable food shortage. With increased body size and well-developed canines, some bears were able to kill ungulates and other mammals, defend carrion from competitors, and protect themselves from other predators. Through this unique combination of being able to be predators, scavengers, and herbivores, they were able to exploit several food bases."

"Small predators are restricted to small prey, so that one benefit of being large is that an animal can kill both small and large prey (Gittleman 1985). For example, brown bears are capable of taking advantage of relatively small animals such as ground squirrels and salmon in circumstances where their abundance makes such behavior energetically or nutritionally worthwhile (e.g., Stonorov and Stokes 1972, Murie 1981). Even so, the ratio between the size of the bear and its prey may be misleading since the predator's large size may be necessary to move heavy stones or earth to catch ground squirrels or to stay warm while standing in cold water for protracted periods while fishing for salmon. In the case of the more carnivorous bear species, their maximum size may have been influenced by the maximum size of generally available prey, as will be discussed below." 
 

[brobear]

Dr. Blaire Van Valkenburgh


Introduction


Bears are unusual members of the order Carnivora, an order which also includes cats, dogs, weasels, civets, and hyenas on land, and seals, sea lions, and walruses in the sea. With the exception of the highly predacious polar bear, bears tend to be the most herbivorous of the carnivores, feeding on fruits and tubers more often than prey. Moreover, all eight species are large, with the smallest of them, the sun bear, weighing more than the wolf, the largest of the canids. Indeed, the polar bear and Kodiak brown bear are currently the largest of all carnivores. Males of these species occasionally weigh in at up to 800 kilograms (1,760 pounds), nearly the size of an adult male bison. Surprisingly, the large size of bears is not achieved through the rapid growth of cubs. In comparison with other carnivores, newborn bear cubs are tiny relative to their mothers and grow slowly.

SPEED AND STRENGTH

All bears have a large head with small ears followed by massive shoulders and a short back and | tail, all of which are supported on thick limbs and broad paws. Compared with big cats, bears have longer snouts and shorter, stiffer backs. Relative to large dogs, bears have bulky legs and much more spreading feet. Unlike these other carnivores, and more like humans, bears walk on the soles of their hindfeet, with their ankle joint positioned just above the ground. This condition is called plantigrade, and differs from the digitigrade posture of cats and dogs, in which the “soles” of the feet are elevated, along with the ankle, and only the toes touch the ground. To understand why bears are built so differendy from cats and dogs, it is essential to explain the benefits of digitigrade feet.

Running around on your toes in a digitigrade posture is advantageous if speed is important. Speed is the product of stride length and stride frequency. Raising the ankle adds length to the part of the limb that determines stride length, that is from the shoulder or hip to the point of contact with the ground. Longer limbs take bigger strides, and digitigrade posture is therefore typical of mammals designed to run. Digitigrade animals also tend to have relatively long bones, or metapodials, making up the sole of the foot, adding further to total limb length. In addition, their limb muscles are much thicker close to the hip or shoulder joint, and taper towards the toes as long, elastic tendons. This construction reduces muscle mass near the ankles and feet, where the limb travels farthest during locomotion, and thus reduces inertial effects.

A The skeletons of a bear and a domestic dog illustrate the difference between plantigrade and digitigrade postures. The dog is digitigrade, standing on its toes with the soles of its feet (metapodials) off the ground. By contrast, the soles of the bear's hindfeet are flat to the ground, as in humans, giving it a plantigrade posture.

If one imagines the additional energy required to walk or run with ankle weights or heavy shoes, then the drawbacks of heavy feet become clear. There are yet further benefits to runners in having long tendinous muscle attachments. Tendons are elastic and act as energy-saving springs when running. They are stretched as the limb is flexed under the weight of the animal and then rebound, propelling the body forward and upward. So, digitigrade posture, long metapodials, and compact muscles with stretchy tendons are typical of carnivores built for speed.

Bears are clearly not built for speed. Although their forefeet are semi-digitigrade, their hind-feet are plantigrade. Moreover, their metapodials are short and their muscles thick throughout the length of the limb. In many ways, bears are built more like badgers than other similar-sized carnivores, such as tigers, and it shows in their speed. The top speed recorded for both black and brown bears is 50 kilometers (30 miles) per hour, whereas the range for the fully digitigrade lion and wolf is 55 to 65 kilometers (35 to 40 miles) per hour.

If bears are not built for speed, then what does the combination of massive limbs, plantigrade hindfeet, cumbersome paws, and a short back provide? Strength and mobility of limb movement are the answers. The stout limbs of bears are capable of producing large forces over a much greater range of motion than those of dogs or even cats. Bears use these capabilities when digging for food or shelter, fishing for salmon, climbing to escape danger, and battling with members of their own species as well as other predators. Imagine a wolf trying to perform a bear hug or climb a tree. Dogs have forfeited these abilities in favor of speed. Cats are more like bears in their range of possible movements, but lack strength. Bears may not be able to outrun danger, but can successfully defend themselves through brute force.

[brobear]

seaworld.org/en/animal-info/animal-infobooks/tiger/physical-characteristics

Cline Morphology

Four out the five living tiger subspecies' morphology (physical structure and appearance) exhibit a cline. A cline occurs when a single species gradually begins to look different over its geographic distribution as it adapts to varying climates and habitats. Therefore the species at the northern end of their geographic distribution may look very different in size, color, hair-density, etc. than their southern counterparts. The Tiger cline depicts subspecies decrease in size and have darker stripe coloration the further south their range extends.
The largest tigers are found in the north, gradually becoming smaller in the south.
Adult male Amur tigers (Panthera tigris altaica) may weigh up to 300 kg. (660 lb) and measure about 3.3 m. (10.9 ft) in length. Females are smaller, weighing between 100 to 167 kg (200 to 370 lb) and measure about 2.6 meters (8.5 ft) in length.
Adult male Bengal tigers (Panthera tigris tigris) weigh about 220 kg (480 lb) and measure about 2.9 m (9.5 ft) in length. Females are slightly smaller with an average weight of 140 kg (300 lb) and 2.5 m (8 ft) in length.
The South China tiger (Panthera tigris amoyensis) are native to South Central China. Males weigh about 150 kg (330 lb) and are about 2.5 m (8 ft) in length. Females weigh are smaller, weighing about 110 kg (240 lb) and are about 2.3 m (7.5 ft) in length.
Adult male Indo-Chinese tigers (Panthera tigris corbetti) may weigh up to 182 kg (400 lb) and measure about 2.8 m (9ft) in length. Females are smaller, weighing about 115 kg (250 lb) and measure about 2.4 meters (8 ft) in length.
Adult male Sumatran tigers (Panthera tigris sumatrae) may weigh up to 120 kg (265 lb) and measure about 2.4 m (8 ft) in length. Females are slightly smaller, weighing about 90 kg (198 lb) and measure about 2.2 m (7 ft) in length.

Legs, Feet & Claws
The hind legs of the tiger are longer than their front legs. This characteristic enables them to leap forward distances up to 10 meters (32.5 ft).
The bones of the tiger's front legs are strong and dense to support the large musculature needed to take down large prey.
The bones in each of the tiger's feet are tightly connected by ligaments enabling them to buffer the impact of landing from running, pouncing and leaping.
Tigers have large padded feet that enable them to silently stalk prey in the Asian jungles.

The claws of the tiger are up to 10 centimeters (4 in) in length and are used to grasp and hold onto prey. Each paw has four of these claws and one specialized claw called a dewclaw. A dewclaw is located farther back on the foot and thereby does not touch the ground when walking. Dewclaws function similarly to thumbs in that they are used for grasping prey and aid in climbing.
Tiger claws are retractable in that ligaments hold them in a protective skin sheath when their not being used. The ligaments are in a relaxed position when the claws are retracted thereby expending no musculature effort. Tigers retract their claws to ensure that they remain sharp for times when they are needed and to tread silently up to unsuspecting prey. Other ligaments will extract the claws when attacking prey or defending themselves which does require musculature effort.
Tiger claws are curved which enables them to superiorly grasp and hold large prey and climb trees head-first. However, the claws' curvature, the tiger's size and weight is a great hindrance in climbing down from trees. Tigers must either crawl backwards or jump down from trees, making them the most inferior climbers of the big cat family.
Head & Collarbone
The skull of the tiger is stout and rounded in shape which provides more support for their powerful jaws.

Tigers' powerful jaw muscles are attached to a bony ridge that lay on top of the skull called the sagittal crest. These muscles function to rapidly clamp down on prey with crushing force.

Tigers have a reduced-sized clavicle (collarbone). This characteristic enables them to attain greater stride lengths because the smaller clavicle allows for a wider, unrestricted range of movement of the scapula (shoulder blade) when running.
Dentition
Tigers have fewer teeth than other carnivores such as dogs (42 teeth) with only 30 teeth.
All cats have deciduous (temporary) teeth that come in within a week or two after birth. These teeth are referred to as milk teeth similar to humans' baby teeth. The milk teeth are eventually replaced by the permanent ones. Therefore they are seldom without a set of teeth.
Tigers have the largest canines of all big cat species ranging in size from 6.4 to 7.6 centimeters (2.5 to 3.0 in) in length. The canines have abundant pressure-sensing nerves that enable the tiger to identify the location needed to sever the neck of its prey.

The back teeth of the tiger are called carnassials which enables the tiger to shear meat from their prey like knife blades. They swallow large-sheared pieces of meat whole.
Tigers are capable of penetrating deeply into their prey because of the large gap between the carnassials (back teeth) and the canines hold prey tightly.
The small incisors located in the front of the mouth (between the two top and bottom canines) enable the tiger to pick off meat and feathers from their prey.
Digestion
The process of converting meat to protein (needed for energy) is significantly less complicated in carnivores than it is to convert grass to protein as some herbivores require. Carnivores do not require the vast amount of microbes (microscopic bacteria) living in their intestines to break down indigestible plant cellulose. Therefore tigers and other carnivores have small and light weight stomachs that do not hinder them when they are accelerating quickly to chase prey.
Tail
A tiger's tail is about one meter in length (3 ft) and may play a part in their visual communication (see communication- vision section).

Tigers use their tail for balance when making sharp turns in pursuit of prey.
Tongue
The tiger's tongue is covered with numerous small, sharp, rear-facing projections called papillae. These papillae gives the tongue is rough, rasping texture and is designed to help strip feathers, fur and meat from prey.

Hair & Coloration
The hair of the tiger provides camouflage, warmth and protection for them.
Tigers possess two types of hair, guard hair and underfur. The guard hairs are longer and more durable than the underfur and mainly function for protection purposes. The primary function of the tiger's hair is for warmth. The underfur traps air which insulates the tiger's body thereby keeping it warm.
Tigers are the only large cat species to have distinctive striping located on both the hair and skin of the tiger.
Many tigers possess stripes on their face, sides, legs and stomach. The striping is varied in width, length, whether they are single or double-looped, coloration from a light brown to dark black and are not symmetrical from one side of the tiger to the other.

The stripe patterning on top of the tiger's head resembles the Chinese character of "wang" which means "king."

The Chinese character of Wang means King.

Tiger Background Coloration:
Many tigers possess the light yellow-orange to deep reddish-orange background coloration.
Black or melanistic colored tigers have been reported but further research is required before assessing whether these sightings were of true melanistic tigers or darker versions of the orange tiger (with few large broad dark stripes).
Tigers with white background coloration are not considered albinos. An albino would be pure white in color (no striping) and would have pink or red eyes. White tigers are leucocystic meaning that they have a recessive gene that causes them to lack dark colors. Therefore they usually have a white color with light to medium brown striping and blue eyes. For unknown reasons, white tigers seem to grow bigger and at a faster rate than their orange counterparts.

There have been reported sightings of blue tigers. There is little evidence supporting this color variation in tigers. However, since the blue colored trait exists in some lynx and bobcat families; it is not ruled out as a possibility.
Tigers have distinctive white circular spots on the backside of their ears. There are two ideas as to the function of these eyespots. One of which is that they function as "false eyes"; making the tiger seem bigger and watchful to a potential predator attacking from the rear. The other idea is that they play a role in aggressive communication because when threatened tigers may twist their ears around so that the backs face forward. This prominently displays the distinctive white markings. The function of the white markings is probably a combination of both ideas.

[brobear]

From Peter - When wild lions hunt large animals, males often participate. They use their forelimbs to grab and their weight to tire it and to bring their victim down. The jaws are used to lock, to hold and to maul, not to kill as fast as possible. This method allows other members of the pride to close in and participate in the killing.

As killing a large and struggling animal can take a lot of time, lion skeletons and, in particular, skulls developed to deal with stress. This means they were reinforced in places where it matters most. If the jaws are used in this way (referring to male lions), there is a lot of pressure on the anterior part of the skull. This, most probably, is the reason the 'snout' of male lions was strengthened and why a bit of length was added. It also resulted in a convex mandibula. The combination of a longer and reinforced 'snout' and a convex mandibula resulted in a longish skull able to deal with pressure in the jaw region. The upper and lower jaw function as parts of a two-part lock.

If you want it visualized, imagine a human, say a professional hunter, with a spike in each hand. The spikes are used to contact a large animal and to hold on. The animal will try to escape by moving away from him. As it is much heavier than he is, he will be dragged forward. This means that the pressure created by the victim will move from his hands to his feet (a horizontal line). Some parts of his skeleton, for this reason, will need to be reinforced and it will most probably start with the bones in his hands and arms.

A solitary hunter can't kill a large animal in this way. Not without damage, I mean. A solitary hunter has to find another way to kill a large animal. He can either strengthen his body (a) or develop efficient killing tools (b).

Bears (a) strengthened their body. They are so strong that they can attack nearly all animals. More robustness and weight, however, also meant they lost the speed needed to contact most prey animals. For this reason, they added fish, carrots, fruits and insects to their diet. This works, but only if it's available. In the northern hemisphere, bears often face long winters. This means that energy deficits can be expected every year. If they live in regions that have good hunters, like big cats, they can consider following and displacing them, but this is not a structural solution. As the food problem never was quite solved, hibernation was the only option. This is the reason that bears always worry about the food problem. Compared to cats, bears are much more food-orientated.

Big cats (b) developed efficient killing tools, but most species living in the northern hemisphere face bears. As they are not large enough to keep them at bay, they often are displaced. Pumas, for this reason, have to hunt more often than expected. This results in energy deficits.

Tigers, however, do quite well in the bear department. Like lions, they hunt large animals. The difference is they hunt on their own, meaning they can't afford a long struggle. This is the reason they developed efficient killing tools. Compared to lions, tigers have larger and more robust canines. The long canines enable them to get to a vital spot fast. This means that they need to be able to concentrate maximum force at the tip of the canines. For this reason, their skull was reinforced in those parts that matter. Tiger skulls can be considered as anchors for the large canines.

As tigers need to be able to exercise vertical pressure, their skulls are vaulted. Skulls of male lions in particular developed to withstand horizontal pressure. This means that a vault isn't needed. Tigers, biters, have relatively short faces, whereas skulls of male lions, maulers, are relatively long.


When captive lions attack humans, they use the same method as wild lions. This means that don't use their skull to kill as fast as possible, but to pin and maul their victim. This means that he or she, if not bitten in the head, stands a small chance to survive a mauling. I know of several cases of keepers mauled in this way. If lionesses attack, they, like tigers and leopards, target the neck or skull in order to kill their victim as fast as possible.

To conclude. Tigers, solitary hunters, have long and robust canines. Their skull developed to exercise maximum pressure at the tip of the canines. This is why they have short and rounded faces and a vaulted skull. Male lions can and do kill in the same way, but pride males in particular also often use their jaws to hold and maul a large animal. The pressure created by the struggling animals travels from nose to tail. For this reason, their skull developed to withstand significant pressure on a horizontal line. This is why male lions don't have a vault, this is why their 'snout' was lengthened and reinforced and this is why the angle of their canines isn't as acute as in tigers. The upper and lower jaw of a male lion serve as two parts of a steel lock. Once in, you can't get out.

All clear? If not, have another look at the pictures I posted. Watch the pressure lines.

[brobear]

jeb.biologists.org/content/jexbio/215/12/2081.full.pdf

SUMMARY

Hibernating bears retain most of their skeletal muscle strength despite drastically reduced weight-bearing activity. Regular neural

activation of muscles is a potential mechanism by which muscle atrophy could be limited. However, both mechanical loading and

neural activity are usually necessary to maintain muscle size. An alternative mechanism is that the signaling pathways related to

the regulation of muscle size could be altered so that neither mechanical nor neural inputs are needed for retaining strength. More

specifically, we hypothesized that muscles in hibernating bears are resistant to a severe reduction in neural activation. To test this

hypothesis, we unilaterally transected the common peroneal nerve, which innervates ankle flexor muscles, in hibernating and

summer-active brown bears (Ursus arctos). In hibernating bears, the long digital extensor (LDE) and cranial tibial (CT)

musculotendon masses on the denervated side decreased after 11weeks post-surgery by 18±11 and 25±10%, respectively,

compared with those in the intact side. In contrast, decreases in musculotendon masses of summer-active bears after denervation

were 61±4 and 58±5% in the LDE and CT, respectively, and significantly different from those of hibernating bears. The decrease

due to denervation in summer-active bears was comparable to that occurring in other mammals. Whole-muscle cross-sectional

areas (CSAs) measured from ultrasound images and myofiber CSAs measured from biopsies decreased similarly to

musculotendon mass. Thus, hibernating bears alter skeletal muscle catabolic pathways regulated by neural activity, and
exploration of these pathways may offer potential solutions for disuse atrophy of muscles.

[brobear]

nrmrsgren.weebly.com/m---movement.html

sites.google.com/site/tigerszucs/tiger-page-4

[brobear]

TIGER
Skeleton and Internal Organs
Humans as well as many other birds and animals, are made with an endoskeleton, meaning that it is inside the body (as opposed to an external shell). The skeleton is made up of hard and strong bones held together by ligaments, rather than cartilaginous structures (as is the case with sharks, for example). The internal organs are then protected inside this sturdy structure.

The structure of the skeleton of a tiger is common to that of the rest of the big cats in the wild, especially the lion.

The skull is designed considerably well. It protect the eyeballs and the brain, and is also built in a way that allows maximum strength in its jaw, which is essential considering it is required when using the hunting methods of biting down on the neck of the prey. The skull is short and rounded, concentrating on all of the support and power into the teeth and jaws. In addition, the tiger is designed better that the humans because a tiger’s septum is made from hard bone, separating the cerebrum and cerebellum and protecting the brain more effectively, whereas the human's is made of a membrane.

Teeth

Tigers have 30 teeth which is peculiar as most carnivores have 42. They back teeth are specially designed to allow them to tear large chunks from their prey. They often swallow the large chunks whole instead of taking the time to chew their food. That is because their digestive system is designed to break down the food. They can eat large amounts of food in one setting when the food is readily available to them.

The tiger's teeth are constructed with a gap between their back teeth and that allows them to bite deep into the neck of their prey. They will use their canine teeth to hold the animal in place until it dies. They small incisors at the front of the mouth are used to remove meat from bones and feathers from their prey. The tongue contains little spikes called papillae. They make the tough rough which helps them to remove fur and feathers from their prey before they eat it.

The longer hind legs of the tiger are made to allow jumping, covering up to 10 meters in a single leap. Their forelegs have a strong and solid bone running through, which reinforces the tiger's landings and makes them able to support a massive amount of muscle tissue. This means that they are as strong as possible, which is important as the tiger because they use their forelimbs to grab and hold onto to struggling prey. The collarbone of the tiger is designed to facilitate the ability to achieve longer strides and running speeds without hindrance.
Tigers are mainly active at dawn and dusk. They are strong swimmers and like spending time in the water. Despite their large size they can run at speeds of 35 - 40 mph and they can leap 30 - 33 ft in length and up to 16 ft high.

The spine of a tiger contains 30 vertebrae (as opposed to our 25) which is a feature that gives the tiger extra strength and flexibility.
The internal organs include:
Lungs – respiration
Heart – circulation of blood
Brain
Liver – processing of chemicals
Stomach – breakdown of food
Kidney – filtering of blood and removal of waste products
Intestines – breakdown and digestion of food
Bladder – holding of urine until ready for excretion

[brobear]

GRIZZLY
Process of Movement
Movement is one of the most important and necessary processes for a grizzly bear. Movement can help in dangerous situations such as:
Defending against dangers (predators, natural disasters)
Catching prey
Finding necessities

Movement is not possible without three vital systems:
Skeletal
Muscular
Nervous

With these three different systems, locomotion (the ability to move) can be achieved. The skeletal system will support the body in environment, protect organs inside the body, and support the movement done by the skeletal muscles (by exerting that contraction from the muscles to the environment - jumping, swimming and any physical movement).

The muscular system will conduct simple actions (pushing and pulling), working in antagonistic pairs with bones to move. Lastly, the nervous system tells the muscles to contract. Because of these three systems, locomotion is achieved.

The skeletal system allows the animal to be supported in sudden changes of support in different environments. Examples are in water when different organism's bodies are made lighter (archimedes force). Another example is in land and air when the body is not supported as if in the water.

As shown in the diagram above, the grizzly bear's skeletal structure is a like to that of a dog or wolf, in where the snout is narrow and their neck is long. Though this is the case, the grizzly bear walks more like a human. Usually mammals walk on their toes (digitigrade) which helps them walk fast. But the grizzly bear puts it foot sole down on the ground just like a human.

The grizzly's hands are big enough to used for catching animals, attacking predators and protecting itself. The legs are also very short but strong enough to support the big body that it has. Both the hands and feet of the grizzly have phalanges which just like many bones of the grizzly, can be found in human anatomy.

Like most living things, a skeleton is a vital system. The skeletal system's process is to do three things, protect, support and provide movement for the body.

Protect
The bone tissue is a both hard and flexible material which helps protect the body from impacts. The bones also act as a cage for the grizzly's delicate organs which help to keep them securely in place.
Support
The skeleton acts as a strong frame for the body which is good for supporting organs, blood etc. inside the body. The skeleton gives shape to the body and supports the soft tissue which enables us to stand up and move.
Move
The skeleton helps in movement as it is made out of strong and rigid material. The body can rely on this skeleton to keep muscles on it to move the body. The skeletal system includes things called 'joints'.

There are three types of important joints:
There are immovable joints, which are used for solid casings for organs. For example, the skull in which it protects the brain and many other important body parts within it. Slightly movable joints, which are flexible enough to change position, but still very solid to keep structure. e.g. the grizzly's vertebrae. Lastly freely movable joints which are used to be regularly moved, such as those for the grizzly's legs (knee). Without joints, the legs and hands of the grizzly bear will not be able to pursue its purpose. (Grabbing, bending, flexing)

There are also three types of bones, long, irregular and fused. Long bones are bones which are high in length and strength. Muscles are powered and attached to these bones (e.g. arm, leg). Irregular bones are irregularly shaped (e.g. vertebrae) and fused bones are bones which are joined together (e.g. ankle bones).

Specialized Cells -
In every single bone, there is a special material called bone marrow. This bone marrow produces blood cells.

Red blood cells - These cells are one of the most important cells in the body. They are the cells which transport oxygen from the lungs to the different parts of the body.

White blood cells - These cells are important in the immune system of all organisms. These white blood cells help to defend against diseases.

The muscular system is the most important part of the movement process. Without muscles, the skeleton won't move and the nervous system has nothing to control. There are three types of muscles: Visceral (found in organs) , cardiac (found only in the heart) and skeletal (on the bones).

The only type of muscle controlled directly by the nervous system is the skeletal muscles. These kinds of muscles stick to the bones using a string material called tendons or generally called nerves. The tendons tell the skeletal muscles to contract or relax. The brain will give this command out and is transmitted from the brain to the spinal cord and then to the nerves connected to it (muscles).

Usually, the skeletal muscles don't work by themselves. They work in pairs called antagonistic muscles. The muscles go against each other - with one contracting and one relaxing. Using tendons and ligaments, this movement is done and the force is exerted to the environment - causing the grizzly's body to move.

Smooth- Smooth muscle cells are found inside organs of the bodies of organisms. They are what make organs move and do what they do. For example, in digestion the smooth muscle cells are what push food down. (Involuntary)

Cardiac- Cardiac muscle cells are only located in the heart, explaining the name 'cardiac muscles'. Its job is to control the automatic pumping of the heart, being directly controlled by the nervous system. It has a rectangular shape. (Involuntary)

Skeletal- These muscles are the most vital in the locomotion partnership. These muscles are directly controlled to the nervous system (Central Nervous Part) and are attached to bones. The skeletal muscles are what enables us to move as it does contracting and relaxing movements. (Voluntary)

The nervous system is the control system of all living things. The nervous system's main part is the central nervous system (CNS) which consists of the brain and the spinal cord (which runs down the vertebrae) From the brain, signals are sent down through the spinal cord, down to all the nerves. Once processed, these nerves send the signals to the connected muscles and then the muscles complete the action.

The second part of the nervous system is the peripheral nervous system (PNS). This essentially is the system which connects the muscles to the CNS - in fact we can call it the bridge to the brain and to the muscles.

If the grizzly bear also detects damage or pain, pain receptors in the skin can tell the CNS what to do (tell which muscle to move).

Specialized Cells-
Neurons- The most important part of the nervous system. It is the connector between the CNS to the muscles of the body.

A metaphorical way to try envision how this cell works is a telephone pole. The telephone pole connects the source of electricity, to our houses. The Neuron cell is what connects the electricity (Signals or commands from the brain) to houses (muscles).

Sensory, Motor and Response
Neurons can be sub divided into 3 different groups,sensory, motor and response.
Sensory neurons are what converts external stimuli (outside feelings such as touch) into internal signals/impulses which are then sent to the brain. As we touch something with ou hands, dendrites from the sensory nerves convert this touch to impulses which enables us to feel.
Motor neurons are neurons located in the vertebrae and and are in charge of telling muscle fibers to contract and relax.
Response neurons are what connects the sensory and motor neurons together. They also translate the signals so that it can be sent to the brain and back to the motor neuron.

[brobear]

Interesting article,
George Stevenson's brain appeared to be sweating, glistening on a bright red plastic picnic plate there in the heat of the day.
It was big as a big man's fist, and all around it, on other picnic plates, were slivers of other brains, like so many thin-sliced neural hors d'oeuvres. Some looked like spreading river deltas, carved deep with winding channels. One looked just like an elk hoof, stuffed tight with morel mushrooms.
With them on the table was a bone-white grizzly bear skull, top lopped to show inside, where Stevenson's juicy brown brain used to be. And beside that was a fully furred grizzly head, guillotined with eyes closed, ears perked up, sharp teeth curving over soft black lips.

These are the grisly tools Dr. Stevenson needs for his presentation: "Grizzly Bear Brain, Central Nervous System Structures."
"These bears are amazing creatures," Stevenson said. "I believe they have the most impressive olfactory system of any animal on the planet. Their nose is the very best."
Generally speaking, national park management, while admittedly complicated, is not brain surgery. Except today, when Stevenson, a pioneering neurosurgeon, has packed the room with Glacier National Park staffers for a brown-bag lunch seminar. Not a few of those brown bags were tucked quickly under chairs as Stevenson pried open the bear head and reached elbow-deep inside to point out its finer details.
Mostly, he was pointing out the snout, a full nine inches of highly evolved scent detection. It is, he said, like no other nose in the world.
A run-of-the-mill dog's sense of smell is roughly 100 times greater than a human's. A good hound dog's nose is perhaps 300 times better.
But a bear's scent system, Stevenson said, is at least seven times better than the hounds.
"It's remarkable," he said. "It's how they know the world."
When humans think about their hometowns, they think in terms of visual maps - down this street to that avenue, turn left at the bank, right at the stoplight. But bears don't see things that way. To get to their favorite huckleberry patch, they don't follow the trail to the tree with the broken limb, and then turn left at the big mossy rock.
"No, they have an olfactory map."
Take the scent of the trail to the smell of the anthill, then follow the smell of water to the perfume of huckleberries.
It is difficult, Stevenson said, for humans to imagine such a way of knowing, but for bears it's essential.
Each spring, when they emerge from the den, they are literally starving. There's no time to wander around and look for food, to look for tracks in the snow and to follow them, perhaps, to a protein meal.
"They have to smell food over huge distances, and then go straight to it," Stevenson said. "If they can't, they die."
An odd hobby
Stevenson was a neurosurgeon from 1965 until 1993, a pioneer of micro-neuro surgery. These days, he lives near Yellowstone National Park and is affiliated with the University of Wyoming.
Of late, he's been combining his lifelong career with his new neighbors the bears, and hopes to create a first-ever neuron-anatomy atlas of bear physiology, using brain anatomy to show how the big bruins work.
The biggest trouble, he said, is finding bear bodies to study. Part of his presentation includes a clip from a National Geographic documentary, in which he and his colleagues are seen sedating a bear and sliding her gently into the cavernous den of a modern MRI machine.
"You have to be very careful," he said, which seems a bit self-evident when you're talking about a bear in a hospital room.
The job is somewhat less nerve-wracking if the bear is dead. Occasionally, Stevenson said, wildlife officials will give him a call when a bear is killed. Then he rushes to Bozeman, where the state of Montana's wildlife laboratory is located - and the bear's head is drained of blood, pumped full of formaldehyde, stabilized and prepped for transport.
Then Stevenson puts it in his plastic cooler, hits the local grocery store for a bag or two of ice and heads for Missoula, where technicians at Community Medical Center work after-hours to make MRI images of bear brains.
It is, he admits, a decidedly odd hobby.
But it is paying off in terms of understanding how grizzly bears think and operate. Stevenson now knows, for instance, that the percentage of a bear's brain devoted to scent is at least five times greater than the percentage of human brain allocated to olfactory systems.
In other words, humans smell in black and white, while bears enjoy the full kaleidoscope.
"A polar bear will walk 100 miles in a straight line to reach a female ready to breed," he said. "That's what the bear's nose can do. They smell a million times better than we do."
A human brain weighs in at about 1,500 grams, huge compared to a 450-gram bear brain. And yet our olfactory bulb is the size of a pencil eraser. The bear's is the size of your thumb. That's a lot of smell power for such a small brain.
And even before the brain, he said, the bear's body is built to sniff.

The black pad on the bear's snout, like a dog's nose, is wired with hundreds upon hundreds of tiny muscles. Bears can manipulate their nostrils the way dexterous people control their nimble fingers.

The smells then travel up two 9-inch channels, with hundreds of times the surface area of a human's nose, to a spot where 10 million nerve strands and a billion receptor cells fire electrical signals directly into the brain, through countless tiny pathways and onto the brain's cribiform plate.

The large hippocampus "remembers" the scent, adding it to the mental map.

Just imagine the blinding brain punch a blast of pepper spray must deliver to that system.

"It's not just heat and discomfort," Stevenson said. "It actually scrambles the brain."

Inside a bear's head.

Stevenson's research, like his lectures, rambles wildly, like a big-bottomed bear across a broad landscape. But stick with him, because he's on the scent, and is headed somewhere particular.

He moves on to bear sight. ("They definitely see in color, but not the way we do. We're totally visual. There's no way bears see as well as you and me.") And bear hearing. ("I think their hearing is quite good. It's nothing compared to that nose, though.") At some point, he said, he'd like to "stain" bear brain cells, so he can track sight and sound directly.

He travels to museums and to the Smithsonian, spinning tales of tracking bear skulls and bear brains from coast to coast. He dives into the cerebellum, the homunculus, the arcane reaches of creased and folded tissue.

He rumbles into the vomer-nasal passages, that curious place between smell and taste, then takes off into the frontal sinus. He stops just long enough to hand you a business card - it says only "Bear Brain Anatomy" - and then launches into the neurophysiology of mammalian auditory pathways.

"This is a whole new way of knowing the species," Stevenson says as he tucks his brain back into its clear plastic jug of formaldehyde. He stacks the picnic plates, and tucks the skulls back in their packing boxes.

"For me, this is absolutely fascinating - like getting inside a bear's head and seeing with his eyes, smelling with his nose. It gives people an idea of how they see us, which is not something people think about very much."

trib.com/news/state-and-regional/...0bf59.html

[brobear]

What is the normal maximum length of a bear's canine teeth? wildfact.com/forum/
Polar bear canine = 5 inches max
Brown bear canine = 4.5 inches max
Cave bear canine = 6 inches max
Short faced bear canine = 6 inches max??? 
   
Adult lion canines are about 10 centimeters long and adult human canines are a little more than 1.5 centimeters long.  ( 3.94 inches ).
 
Bengal tigers have the longest canine teeth of any living felid measuring approximately 4 inches (100 millimetres) in large individuals.  
 
animalcorner.co.uk/animals/bengal-tigers/ 
 
www.nationalgeographic.org/activity/big-cats-big-teeth/
 

[brobear]

Yellowstone National Park - Home of America's most famous grizzlies. A beautiful but hostile environment where grizzly food selections are poor.
www.nps.gov/yell/learn/yellowstone-grizzly-bear-facts.htm

From Yellowstone Science 23(2): pages 44-45.
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Ursidae
Subfamily: Ursinae
Genus: Ursus (Latin word meaning "bear")

Species: arctos (Greek word meaning "bear")
Common Names: grizzly bear, brown bear, silvertip
Names in Other Languages: Spanish: Oso café/grande, French: Ours brun
Group of Bears: sleuth
Life Span: 20-30 years; oldest known in GYE 31 years
Pelage: from black to brown to light blonde
Locomotion: tetrapedal, plantigrade
Speed: 35-40 mph
Claw Length: average 1.8 inches (45 mm), longest 5.9inches (150 mm);claw length and shape allow efficient digging of foods from the ground but are less efficient for tree climbing than black bear claws
Tree Climbing Ability: cubs and younger, smaller bears are proficient tree climbers; however, adult male and female grizzly bears are also capable of climbing trees
Tail Length: 3-4.5 inches
Body Temperature: 36.5-38.5°C (98-101°F) during active season;34.4-35°C (94-95°F) during hibernation
Respiration: 6-10 per minute; <1 per minute during hibernation
Heart Rate: 40-50 beats per minute; 8-19 beats per minute during hibernation
Eyes: blue at birth, brown as adults, and greenish yellow in headlights in the dark
Vision: possibly equal to human vision; exhibits color vision and excellent night vision
Genetics: 74 diploid chromosomes
Number of Bones: male = 225, female = 224 (not counting the metapodial sesamoid bones and hyoid bones)
Number of Teeth: 42
Dental Formulae: I 3/3, C 1/1, P 4/4, M 2/3 = 42 (upper [each side] = 3 incisors, 1 canine, 4 premolars, 2 molars; lower [each side] = 3 incisors, 1 canine, 4 premolars, 3 molars)
Feeding Habits: omnivorous carnivore; opportunistic generalist
Caloric Requirements: normal (May-Sept): 5,000-8,000 kcal/day; hyperphagia: 20,000 kcal/day; hibernation 4,000 kcal/day
Average Body Mass: adult male = 413 lb (187 kg); adult female = 269 lb (122 kg)
Heaviest Known Weight in GYE: adult male = 715 lb (324 kg); adult female = 436 lb (198 kg)
Estimated Number Currently Living in the GYE: 714
Area Occupied in GYE: 58,000 km2 (22,394 mi2)
Average Home Range Size in GYE: males = 874 km2;females = 281 km2
Social Behavior: generally solitary except at concentrated food sources (ungulate carcasses, trout spawning streams, moth aggregation sites, etc.), during courtship, or when accompanied by young
Adult Sex Ratio: 50:50 (M/F)
Age Composition: 19% cubs, 13% yearlings, 25% subadults (2-4 yrs.), 43% adults
Period of Courtship: mid-May through mid-July
Delayed Implantation: grizzly bears exhibit obligate delayed implantation or embryonic diapause
Gestation: 235 days (implantation of embryo delayed until late November/early December)
Birth Period: late January/early February
Birth Location: in winter den
Den Entry: pregnant females –1st week November;other females –2nd week November;males –2nd week November
Average Denning Duration: females with cubs –171 days;other females –151 days;males –131 days
Den Emergence: males –4th week March; other females –3rd week April;pregnant females –4th week April
Typical Den Types: excavated (i.e., dug) = 91%;natural cavity = 6%;snow = 3%
True Hibernators?: yes, although bears are shallow hibernators and do not drop their body temperatures as low as many hibernators, they are considered to be true hibernators
Weight Loss During Hibernation: 15-30% of body weight
Average Age of First Reproduction (FEMALES): 5.8 years
Litter Size: range 1-4 cubs per litter; average 2.04 cubs per litter
Interbirth Interval: average = 2.78 years
Reproductive Rate: 0.336 female cubs/female/year
Survival Rate: cubs = 55%;yearlings = 54%;subadults = 95%; adult females = 95%;adult males = 95%
Causes of Mortality (GYE): human causes = 85%;natural causes = 15%
Period of Maternal Care: 18 to 42 months;average = 30 months
Nursing Characteristics: females have three pairs of functional nipples
Bear Milk: 30% fat, 15% protein
Cubs' Eyes Open: at approximately 21 days
Weaning: nutritional dependence on mother's milk ends at approximately 24 weeks;offspring may continue to nurse occasionally until they separate from their mothers

[brobear]

wild-lifeanimal.blogspot.com/2013/01/brown-bear-stronger-animal.html

Brown Bear The Stronger Animal

Brown bears (Ursus arctos) is a large bear distributed in most northern Eurasia and North America. Bear adults generally have a weight between 100 and 635 kg (220 and 1,400 lb) and the largest subspecies, Kodiak Bear, rivals the polar bear as the largest member of the bear family and as the largest land carnivores.

There are several recognized subspecies within the brown bear species. In North America, two types are generally recognized, the coastal brown bear and the inland grizzly bears, and two broad types can define all brown bear subspecies. An adult grizzly in the Yukon interior life may weigh as little as 80 kg (180 lb), while the adult brown bears in Alaska live near shore on diet, nutritional stable spawning salmon may weigh as much as 680 kg (1,500 lb). Exact amount of overall brown subspecies remains in debate.

While the brown bear range has shrunk and has faced local extinctions, still listed as a species of concern by the IUCN with a total population of around 200,000. In 2012, this and the American black bear is the only bear species are not classified as endangered by the IUCN. However, the subspecies of California, North Africa (Atlas bear), and Mexico hunted to extinction in the nineteenth and twentieth and Marsican brown bears in central Italy is believed to have a population of only 30 to 40 bears.

Prime rate, including the brown bear from Russia, the United States (most of Alaska), Canada, the Carpathian region (especially Romania, but also Ukraine, Slovakia, Poland, and so on), the Balkans, Sweden and Finland, where it is the national animal. Brown bear is the most widely distributed of all bears.

Brown bears have long, thick fur, with manes long enough in the back of the neck. In India, brown bears can be reddish with silver tips, while in China, brown bears are bicolored with a yellow-brown tunic or white on her shoulder. North America may Grizzlies dark brown (almost black) to cream (almost white) or yellowish brown. Black hair usually have white tips. Winter fur is very thick and long, especially in northern subspecies, and can reach 11 to 12 centimeters (4 to 5) in the Withers. Winter thin hair, but rough to the touch. Summer fur is much shorter and sparser, and its length and density varies geographically.

Brown bears have very large claws and curved, those attending the forelimbs become longer than the hind feet. They can reach 5 to 6 cm (2.0 to 2.4 in) and sometimes 7 to 10 cm (2.8 to 3.9 in) along the curve. They are generally dark with a light tip, with some forms having completely light claws. Brown bear claws are longer and straighter than American black bears.

Blunt claws, while those of black bears sharp. Because of the structure of their claws, as well as their excess weight, adult brown bears can not climb trees as the two species can black bears. The claws of the brown bear is big enough. Hind legs adult bears were found usually measure 21 to 36 cm (8.3 to 14 in) long, with a large Kodiak bear has been measured up to 46 cm (18 in.) along their hind legs.

Adults have a big, very built concave skulls, which are large in body proportions. High forehead and skull steeply.The projections growing up well when compared with those from the recent Asian black bears have a sagittal crest not exceed more than 19-20% of the total length of the skull, while the former has a sagittal crest consists of up to 40 - 41% of the length of the skull. Weaker skull projections developed in sows than in boars.

Brain shell is relatively small and elongated. There are a lot of geographic variation in the skull, and presents itself especially in dimension. Grizzlies, for example, tend to have flattering profile of European and American coastal brown bears. Russian bears tend skull length from 31.5 to 45.5 cm (12.4 to 17.9 in) for males, and from 27.5 to 39.7 cm (10.8 to 15.6 in) for females. Zygomatic arch width in males is 17.5 to 27.7 cm (6.9 to 11 in.), and 14.7 to 24.7 cm (5.8 to 9.7 in) in women. Brown bears have very strong teeth: a relatively large incisors and canine teeth large, highly curved lower. Three maxillary first molar undeveloped and single crowned with one root.

Molar on both smaller than the other, and usually not in adults. It is usually lost at an early age, leaving no trace alveolus in the jaw. The first three of the mandibular molars are very weak, and often lost at an early age. Although they have powerful jaws, brown bear jaws are not able to breach large bones with the ease see hyenas.

The Brown Bear is the most different sizes of species extant bears. Dimensions of brown bears fluctuate very greatly according to sex, age, individual, geographic location, and season. The normal range of physical dimensions for a brown bear is the length of the head-and-body 1.4 to 2.8 m (4.6 to 9.2 ft) and a shoulder height of 70 to 153 cm (28 to 60 in). Males always larger than the female, usually with around 30% more weight in the race. Tail relatively short, ranging from 6 to 22 cm (2.4 to 8.7 in) in length.Young year usually weighs 2-27 kg (4.4 to 60 lb), while yearlings usually weighs 9-37 kg (20 to 82 lb).

In general, expensive brown bear at least when they emerge from hibernation in the spring and then reach peak weight when preparing for hibernation in the fall (as they often gorge on large food items).

Several subspecies showed considerable variation. While the Eurasian brown bear (U. a. Arctos) and grizzly bear (U. a horribilis.) From Northern Europe, Yellowstone National Park or interior Alaska seasonal average weight between 115 and 360 kg (250 and 790 lb), bears the yukon Delta, British Columbia interior, Jasper National Park and southern Europe may weigh 55-155 kg (120-340 lb) on average. From Syria bear (U. a syriacus.) And Gobi Desert (U. a gobiensis.) Subspecies is about the same mass as small Eurasian brown and grizzly bear and can measure very small as 1 m (3.3 ft) in head-and-long body.

At the other end of the scale of interior brown bears, grizzly normal, brown bear Eurasian and East Siberian brown bear (U. a collaris.) Has been weighing up to 680 kg (1,500 lb), 481 kg (1,060 lb) and 600 kg (1,300 lb ), respectively.

Due to lack of genetic variation within subspecies, environmental conditions in a particular region may play the biggest part in the weight variation. Interior brown bears are generally smaller than often perceived, to be around the same weight as the average African lions average estimate of 180 kg (400 lb) in males and 135 kg (300 lb) in females.

Largest inland brown bear subspecies appears to be Ussuri brown bear (U. a lasiotus.), Probably ancestors of modern American grizzly, which in turn is comparable to the size of a bear littoral as described below.

Brown bears are found in the coastal areas of Alaska and the Russian Far East is the largest. Kodiak bears are the largest subspecies (U. a. Middendorffi), followed by the Kamchatka brown bear (U. a beringianus.), Though bears from other coastal areas of East Asia and western North America can be comparably large. In the districts, the average girl from 181.4 to 318 kg (400 to 700 lb) and average men 272-635 kg (600 to 1,400 lb). It is not uncommon for male Kodiak bear weight up to 680 kg (1,500 lb) in the fall with some specimens reaching 780 kg (1,700 lb) or more.

[brobear]

Example: How should we compare the girth of a grizzly with that of a tiger? 
 
This is my opinion and to be completely honest, I can not imagine any other method being more accurate:
First, you find a healthy full-grown male specimen of each of the two species which measure the same head-and-body length or the same bipedal height. You will find that head-and-body length normally compares very closely with bipedal height. Then you measure the girth, such as neck girth and chest girth. -just that simple.  
To make this comparison method even more clear: If we were to compare a reticulated python with a green anaconda, we would measure the girth of two snakes of equal length - savvy?

[brobear]

I just posted over at wildfact.com/forum/ using Bengal tiger data by pckts: a Bengal tiger with a head-and-body-length advantage of nearly a foot has a chest girth equal to the smaller grizzly.

Comparing Bengal tiger ( head-and-body length 6 feet 3 inches ) to Yellowstone grizzly ( head-and-body length 5 feet 5 inches ).

Bengal tiger - Chest girth = 4 feet 3 inches / Shoulder height = 3 feet 3 inches / Weight = 489 pounds.

Yellowstone grizzly - Chest girth = 4 feet 3 inches / Shoulder height = 3 feet 1 inch / Weight = 426 pounds. 
   
With nearly a foot advantage in length, the Bengal tiger only has a weight advantage of only 63 pounds. 

[brobear]

( IMO) There is a reason why bears are more robust than cats. A cat is a full-time predator. He is designed for a combination needed for successful hunting and killing. For the big cats, this combination includes a need for stealth, running speed, agility, quick reflexes, leaping ability, the strength to pull down heavy prey animals, and the tools of the trade needed.

A grizzly is an omnivore and an opportunist. He is a part-time hunter. He can afford the extra bulk. In a way of looking at it, a grizzly is rather like an odd mix of tiger and buffalo. He is both predator and herbivore. Just recently a poster over at wildfact.com/forum/ was attempting to claim that a tiger has a greater girth than a grizzly at size-parity. He couldn't be any wronger.
Posters of the big cat fan-boy persuasion used to argue that a grizzly would lose to a big cat in a face-off because the cat is a full-time predator and fully carnivorous. Truth is, the reason a grizzly can defeat the big cat rests in the fact that the bear is an omnivore. As an omnivore, the grizzly can afford the extra bulk which provides greater brute strength. Also, as an omnivore, the grizzly is a "Jack-of-all-Trades" meaning he has a greater need of intelligence. Bears are substantially smarter than cats. With his ape-like intelligence, his bull-like brute strength, and with the tools of a predator, the grizzly is the normal winner in a face-off with a big cat.