Paws and Jaws

[brobear]

MAN MEETS GRIZZLY - Gathered by F.M.Young - 1980.
When mature, a grizzly has claws from four to seven inches long; not curved and sharp like the black bear's, but large, slightly curved, and somewhat concave on the underside, very much resembling a chisel, and well-adapted for digging, tearing logs apart, and fighting, when necessary. With these unique tools the grizzly will remove huge quantities of earth and rocks quickly in pursuit of a rodent morsel or dig a pit large enough to bury the carcass of a range bull, which he carefully covers up to insure a future meal for himself. And of course the claws are formidable weapons in combat, cutting like razors and strong as steel. 
 

[brobear]

Grizzly canine teeth are not so long as those of a lion or a tiger, but long enough. They are built thick and are deeply rooted - made for brawling.
 
                                                

[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???

[brobear]

How does the bite-force of the grizzly compare with that of other bears?  
 
                                                             

[brobear]

The 91 kg ( 200 pounds ) Asian bear listed is surprisingly, an Asiatic black bear. Of all the living bears, the grizzly ( brown bear ) has the strongest bite-force. However, pound-for-pound, this changes: Giant panda first, sun bear in second place, and grizzly in third. Only because of his greater size does the grizzly come out in first place. The weakest bite-force among living bears ( not shown on the chart in post ) is that of the sloth bear.

[brobear]

The Brown bears also got the broadest canine teeth in proportion...( picture and information from GrizzlyClaws ). 
 
                                                                        

[brobear]

Strong jaws complemented with strong teeth.
                                                                        

[brobear]

The Grizzly Bear - The Narrative of a Hunter-Naturalist by William H. Wright - published in 1909.
This book is dedicated with the respect, admiration, and affection of the author to the noblest wild animal of North America, the grizzly bear.
These little animals hibernate, as do the grizzlies, but they turn in earlier; and in a region where they are found the bears take great delight in unearthing them, and sometimes will dig out carloads of earth and rocks to secure a small feast of the little fellows. This is the last food the grizzly obtains before he goes into his long winter sleep.
The claws of the grizzly are well adapted for this peculiar sort of work; yet, long and strong as they are, so much of it does he have to do that, by the time he is ready to go into winter quarters, they are worn down to the quick, and not much, if any, longer than those of the black bear. After his long winter's sleep, however, when he emerges from his den in the spring, he is once more armed with strong curved claws, from four to six inches long. In those parts of the country where he does not have to hustle so hard for roots and ground squirrels - for instance, in some parts of Wyoming, central Idaho, and Montana - the grizzly does not wear his claws down so close. Yet he seems, on the whole, to attain a larger growth where he has to work most.

[brobear]

sites.google.com/a/bsdvt.org/jackson-s-amazing-world/brown-bears

Do you want to learn about grizzly bears and brown bears? Well then, you came to the right place. This page you are going to learn about the mighty Brown bear and the fierce grizzly. You're going to learn about how big they are. I am going to tell you what they eat. Also, you're going to learn about the old wise grizzly bear, Ginger. Also, you are going to learn about the great Kodiak island. Also, some old bears, there are other old bears, too.
An average person weighs 155 pounds, but the mighty brown bear weighs 700 pounds. That's 4 times the size of humans. That's making our weight seem nothing compared to brown bears. Did you know that the Brown Bear does not live in VT?

The mighty brown bear has quite an appetite. It eats grass, fruit, insects, roots, plants, small animals, foxes, young deer, sheep, fish/salmon, and rodents. The Brown Bear prefers salmon.

The brown bear roams around the forests and mountains of northern North America, Europe, and Asia. Also the brown bears are found at Brooks Falls. Brown bears are there because there's a lot of salmon and that's the food they prefer. Also thats a place where they keep them safe. The brown bear also lives on Kodiak island. Also the Kodiak bear lives on Kodiak island. Kodiak island is in Alaska.

The mighty brown bear can get up to 35 years old, that's older than me. In fact that's 24 years older than me. That's 15-5 years older than the biggest bear the polar bear.
In Conclusion: This is how amazing and fascinating the MIGHTY brown bear is.
Kodiak Island
You're probably thinking what's so special about Kodiak island well in this paragraph i'm going to tell you. Kodiak island is the home of the kodiak bear also the fierce grizzly bear and the mighty brown bear. Sadly there is only 3,500 kodiak bears left in the world. The kodiak bear is the largest bear in the world it can get up to 10 ft on its hind legs. Kodiak island is located in the alaskan island.
Interesting Facts About bears
The Latin word for Bear is Ursus.
There are many subspecies of brown bear.
Grizzly Bear Documentary
The Fierce mean grizzly has brown and dark brown fur. It is a lookalike of it's cousin brown bear. The grizzly bear is a little smaller than the brown bear but it may be smaller but it is stronger than the brown bear.


The grizzly bear has the strongest bite out of all bears the grizzly bear it has a whopping 1250 psi and the polar bear has 1235 that's 15 psi less than the fierce grizzly bear. The fierce grizzly bear is the strongest type of bear today.

A male grizzly bear is 680 pounds and a female is 290-440 that is 160 less than the male. That is equal to three grown men well if you want to be precise 12 pounds more than three grown men.

The grizzly bear is surprisingly almost ten feet on their hind legs. They are 9'8" on their hind legs. When the grizzly bear is not on its hind legs it's 4'9" tall.
Ginger The Grizzly Bear
Ginger is the oldest known grizzly bear. She was 40 years old. Ginger was the oldest bear to live at any North American zoo. Ginger died September 11 2015 at Columbus Ohio Zoo at 11:14 Thursday. Before Ginger died, a couple years ago, she was diagnosed with arthritis. Usually geriatric bears get it. (Geriatric means old.) She even outlived the other record, which was 39 years old. A usual female grizzly bear lives for about 26.8 years. She was 13.2 years older than a regular female grizzly bear. Carrie Pratt, curator of the North America region, said that the loss was hard for them because a lot of the keepers grew up with her. Working with her as seasonal team members then caring for her full time. Keepers for their whole careers and she also said it was very difficult.

Ginger was born in 1976. At her first long term home at the Cleveland Zoo she gave birth to five cubs, one in 1980 another in 1981 and three more in 1985. She later moved to Columbus, Ohio in November, 1987 where she met Growly, the pair had two cubs Sugar and Spicey, about two years later. Ginger and Growly became inseparable, which means they can't be separated, During their 15 year cohabitation. After Growly died in 2002. Ginger took an active interest in the new arrival of brown bear cubs (now full grown), Brutus and Buckeye.

[brobear]

www.smallanimalplanet.com/strongest-animal-jaw-strength/

This is just one of many online sites depicting animal bite-force. According to this particular site, the grizzly has a stronger bite force than either the lion or the tiger. Even though the grizzly is my favorite, I would have to see further evidence to accept this as fact... Grey Wolf - 406 psi, Lion - 691 psi, Tiger - 950 psi, Hyena - 1100 psi, Grizzly - 1250 psi, and Gorilla - 1300 psi.

*Note: Measuring bite force is not an exact science. I watched a nature documentary once and was surprised that the silverback gorilla and the boar grizzly have a similar bite force. Contrary to the results given here, I believe that lions and tigers have stronger jaws than a grizzly.

[brobear]

www.allgrizzly.org/skull--dentition

The figure immediately above provides a bit more information on the distribution and magnitude of the bite force generated by the teeth of various carnivores; work that was done primarily by Per Christiansen. A distinction is made between the bite force delivered by the canines versus the bite force delivered by the cheek teeth (i.e., molars/carnassials). Bite force is represented both in absolute terms (Newtons) as well as in terms standardized to the size of the associated animal. Each dot corresponds to a species, with bears denoted by a brown dot, and each bear species identified by a 3-letter acronym. The line represents a condition where the force delivered by the cheek teeth is equal to the force delivered by the canines.

Viewed in absolute terms (Panel B), bite force becomes ever more loaded on the molars or carnassials the greater the force that is delivered. Hence there is a trend downward in the ratio of canine force to molar force as force increases. Also of note, bears along with some of the largest cats deliver the greatest force of all the carnivores. Much of this is a function of size, which means that size matter when it comes to absolute bite force.

When standardized to size (Panel A), bears look less extreme. They actually tend to cluster lower down the curve, which means that, given their size, they are less well built to deliver bite force compared to many other carnivore species, especially of the Felids and Canids. The noteworthy exceptions are the polar bear (Uma) and the giant panda (Ame), which is not surprising. The polar bear is the most carnivorous of all bears (meaning, it needs to grasp and hold prey), whereas the panda is the most herbivorous (meaning it needs a powerful bite to grind the bamboo that comprises most of its diet).

[brobear]

shaggygod.proboards.com/

BEAR-INDUCED INJURIES
Bear-inflicted injuries range from minor, treated on an outpatient basis, to
complex, requiring hospitalization and surgery, typically resulting in significant cosmetic
and functional disability. In this regard, bear attacks are similar to most other animal
attacks, particularly those inflicted by large animals.
The character of such injuries is determined in part by the three main sources:
teeth, claws, and paws. The teeth of bears, especially the canines, are large and sturdy.
Although the teeth are not particularly sharp, the power of the jaw muscles allows the
teeth to penetrate deep into soft tissues and to fracture facial bones and bones of the hand
and forearm with ease. The trauma characteristically results from punctures, with
shearing, tearing, and crushing forces (Figure 43-20).
The claws are another important source of trauma. Although the claws on the
front pads can be as long as human fingers, they are not particularly sharp on grizzlies
and polar bears. The bear’s shoulders, however, provide the force and speed that allows
claws to cause significant soft tissue damage in a scraping maneuver that results in deep,
parallel gashes. Because black bear claws are sharper and more curved, the cuts tend to
have sharper, less ragged edges.
The bear paw is capable of delivering a powerful force, resulting in significant
blunt trauma, particularly to the head and neck, ribcage, and abdominal cavity, especially
solid organ rupture. Therefore victims of bear attacks should be evaluated for occult
blunt trauma.

ORIGINAL PAPER
Large carnivore attacks on hominins during the Pleistocene:a forensic approach with a Neanderthal example
Edgard Camarós

www.academia.edu/12436456/Large_carnivore_attacks_on_hominins_during_the_Pleistocene_A_forensic_approach_with_a_Neanderthal_example

"...The present observation of a total of 45 forensic cases iscommensurate with this known attack pattern of bears.Figure 2a shows that within the 38 case studies with bone modifications, the main bone damage is located in the head zone(skullandmandible)and upper limbs(clavicle,humerus,radius, ulna, metacarpals, and hand phalanges). Bears tend toattack the victims head, causing wounds and fractures in that zone, and humans react by protecting themselves with their arms, causing damage in that region. Long-bone diaphyseal linear, comminuted, and segmental fractures in the upper limb are not rare,and finger amputation is also common(Dharetal.2008). All these bony injuries are frequently associated with general soft-tissue wounds (Fig. 2b), as observed in other cases (Rasool et al. 2010). Therefore, bone modification after a bear attack would appear to occur in the body areas where other general non-bony wounds are inflicted by the animal..."

www.academia.edu/12436456/Large_carnivore_attacks_on_hominins_during_the_Pleistocene_A_forensic_approach_with_a_Neanderthal_example

Unfortunately, I don't have access to this paper,but ....
Grizzly bear (Ursus arctos horribilis) locomotion: gaits and ground reaction forces
Catherine L. Shine, Skylar Penberthy, Charles T. Robbins, O. Lynne Nelson, Craig P. McGowan

ABSTRACT

Locomotion of plantigrade generalists has been relatively little studied compared with more specialised postures even though plantigrady is ancestral among quadrupeds. Bears (Ursidae) are a representative family for plantigrade carnivorans, they have the majority of the morphological characteristics identified for plantigrade species, and they have the full range of generalist behaviours. This study compared the locomotion of adult grizzly bears (Ursus arctos horribilis Linnaeus 1758), including stride parameters, gaits and analysis of three-dimensional ground reaction forces, with that of previously studied quadrupeds. At slow to moderate speeds, grizzly bears use walks, running walks and canters. Vertical ground reaction forces demonstrated the typical M-shaped curve for walks; however, this was significantly more pronounced in the hindlimb. The rate of force development was also significantly higher for the hindlimbs than for the forelimbs at all speeds. Mediolateral forces were significantly higher than would be expected for a large erect mammal, almost to the extent of a sprawling crocodilian. There may be morphological or energetic explanations for the use of the running walk rather than the trot. The high medial forces (produced from a lateral push by the animal) could be caused by frontal plane movement of the carpus and elbow by bears. Overall, while grizzly bears share some similarities with large cursorial species, their locomotor kinetics have unique characteristics. Additional studies are needed to determine whether these characters are a feature of all bears or plantigrade species.

VGRF = vertical ground reaction force.
*Brown bears share some similarities with large cursorial species, their locomotor kinetics have unique characteristics.
*Vertical ground reaction forces is significantly more pronounced in the hindlimb,however,VGRF in forelim is still relatively high.
"The high medial forces (produced from a lateral push by the animal) could be caused by frontal plane movement of the carpus and elbow by bears"
It forced me to focused on the carpus of brown bears.

[brobear]

Interesting continue from post #19.
Sylvie McKenzie said she was driving along a highway a few kilometres west of Jasper when she noticed two bears running along the road ahead.She said she slowed down to let the bears cross the road, but only the female bear did so.

The second bear – a male – simply stopped and stared at her.

McKenzie said she then started driving, putting her car between the two bears.

Sylvie McKenzie
Asked whether she has any advice for drivers caught in the same situation in the future, McKenzie had simple advice: 'Stop, turn around, wait for a few minutes and go back.' (CBC)

"The male didn't like it at all, so he decided to take his feet, charge and hit my car with his two front paws," she said. "[He] just came and pounced on my car with full force and full speed."

McKenzie said the car rocked violently when the bear hit it, giving her a close-up view of the bear’s face.

"I could see his teeth, the drool on his face. I tried to speed up and put my foot on the gas pedal to get away as fast as I could."

Later, she found grizzly prints all over the side of her car, along with two big dents and several scratches.
It seem that carpal bone have a high resistance to mechanical deformation. Grizzly bear front paws are surprisingly heavy,maybe due to massive carpal bones?

This is the most accurate description of the striking ability IMHO:
"...The attack of a Bear is usually sudden and rapid, and he either tries to deal his opponent a blow with a forepaw by executing a rapid and violent movement to the side ,or he quickly trots up to his enemy ,suddenly lift himself on his hind-legs in the immediate proximity of his foe whom he tries to knock down with a violent stroke of the front-paw,or else he deals him a sound blow and gives him a quick bite..."

[brobear]

shaggygod.proboards.com/

Evolutionary implications of bite mechanics and feeding ecology in bears

Bite forces (BFs) based on a dry skull static model were computed for 122 specimens of all eight species of extant ursids. It was found that the giant panda has high BFs for its body size, and large moment arms about the temporomandibular joint, both muscle inlever moment arms and outlever moment arms to the carnassial and canine. The insectivorous sloth bear and to some extent the omnivorous black bears were the opposite. The small sun bear has very large canines and high BFs, which are not well understood, but could potentially be related to its frequent opening of tropical hardwood trees in pursuit of insects. Force profiles along the lower jaw revealed significant differences among the various species, both related to diet and inferred applied BFs. The panda is the only specialized ursid with respect to craniodental morphology and BFs, but is still unspecialized for herbivory compared with other large, herbivorous mammals, probably owing to a rather short evolutionary history, but possibly its morphology is constrained by genealogy. The low BFs in the sloth bear and its mandibular force profiles are derived for a diet of insects and fruit, requiring only low BFs and largely dorsoventral bite moments. In contrast, the unspecialized morphology and moderate BFs relative to body size of the polar bear and spectacled bear are probably also a result of a short evolutionary history.

Adaptation of the muscles of mastication to the flat skull feature in the polar bear (Ursus maritimus).

The muscles of mastication of the polar bear (Ursus maritimus) and those of the brown bear (U. arctos) were examined by anatomical approach. In addition, the examination of the skull was carried out in the polar bear, brown bear and giant panda (Ailuropoda melanoleuca). In the polar bear, the rostro-ventral part of the superficial layer of the M. masseter possessed the abundant fleshy portion folded in the rostral and lateral directions like an accordion. Moreover, the rostro-medial area of the superficial layer became hollow in the nuchal direction when the mouth was closed. The M. temporalis of the polar bear covered up the anterior border of the coronoid process of the mandible and occupied the almost entire area of the cranial surface. The M. pterygoideus medialis of the polar bear was inserted on the ventral border of the mandible and on the ventral part of the temporal bone more widely than that of the brown bear. As results of our measurements of the mandible, an effect of the leverage in the polar bear was the smallest in three species. In the polar bear, the skull was flat, and the space between zygomatic arch and ventral border of the mandible, occupied by the M. masseter was the narrowest. It is suggested that the muscles of mastication of the polar bear is adapted to the flat skull feature for supplementing the functions.

Text extract from Naturalist Terry Domico:


"The brown bear is stout and rather chunky in shape, with a large hump of fat and muscle over the shoulders and very long claws. It has a wide, massive head that some people describe as being somewhat "dish faced" in appearance. That big head is equipped with extremely powerful jaws. I once saw a big male, trapped in a leg snare set by researchers, take out its frustration on some neighboring trees. In one bite he bit completely through a 4-inch (10-cm) -diameter pine, snapping it off. It also chewed through several 6- and 8-inch (15- and 20-cm) -diameter trees. One stump looked as though it had been dynamited. When we slammed the sharp end of a geologist's pick into the trunk of one of those trees, it only penetrated about 1.5 inches (3.8 cm) into the wood."

Domico, T. and M. Newman. 1988. Bears of the world. Facts on File.

[brobear]

shaggygod.proboards.com/

Measurement of a bear's bite force (depending on which specie of bear) is not an easy task. Some variables are difficult to quantify. There is anecdotal evidence of a bear's bite force strength as explained from the literature (see relating posts/threads) and similarly there are data provided in the form of popular media by bear specialists/biologist:


"Grizzly bears have a bite-force of over 8,000,000 pascals, enough to crush a bowling ball."

1 Pascal = 1 N/m2.

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

[brobear]

California Grizzly by Tracy I. Storer and Lloyd Tevis, Jr.

The feet of bears are large because the animals are plantigrade, the palm or sole as well as the toes being provided with durable pads that regularly make contact with the ground ( fig. 7 ). In this respect they differ from the speedier dogs, cats, and other lithe carnivores that habitually run on their toes. The forefoot of grizzlies - and that of black bears - has a large pad on the palm that is wider than long and somewhat rectangular. Each of the five toes has a small oval pad. The hind foot of the California grizzly was a huge structure in fully adult males. For example, that of the big individual which served as the type of Ursus magister ( USNM 160155 ) measured 12 inches in length without the claws, and 8 inches in greatest breadth. The sole pad is crudely triangular, with the base foremost against the pads of the five toes. All the pads are surfaced with tough, cornified epidermis over a substantial mass of resistant connective tissue. This covering of the foot is the sturdy, self-renewing "shoe."

The front claws of grizzlies, as compared with those of black bears, are heavier, longer, broader, and only slightly curved. They serve the grizzlies in their extensive digging operations for bulbs, roots, and rodents and in fighting. Many human beings were deeply gashed by these great hooks that are powered by heavy arm and shoulder muscles. The length and size of the claws vary with age, and possibly bears of different regions had some differences in relative proportions and dimensions of these members. The activities of the animals also affected the claws. According to X'antus, grizzlies near Fort Tejon had claws much worn from digging. Of the grizzlies in the Rockies, Mills ( 1919 : 91 ) wrote that when the animals entered hibernation the claws were worn, blunt, and broken, but when they emerged from the winter rest period the claws were long and moderately pointed. Replacement growth would not have been conspicuous in lowland California grizzlies that did not hibernate.

[brobear]

Man Meets Grizzly by Young and Beyers.
When mature, a grizzly has claws from four to seven inches long; not curved and sharp like the black bear's, but large, slightly curved, and somewhat concave on the underside, very much resembling a chisel, and well-adapted for digging, tearing logs apart, and fighting, when necessary. With these unique tools the grizzly will remove huge quantities of earth and rocks quickly in pursuit of a rodent morsel or dig a pit large enough to bury the carcass of a range bull, which he carefully covers up to insure a future meal for himself. And of course the claws are formidable weapons in combat, cutting like razors and strong as steel.

[brobear]

Franklin321... For one, I believe in regards to claws as weapons, those of ursines are more efficient, whereas the claws of a feline are multifunctional, they are closer to what we would see as tools; the claws of bears can slash and lacerate with precision, being about as sharp, although not as curved in design as those of a felid.

Whereas, a feline's claws are closer to meat-hooks, and better at holding prey, because of this a slash could be slowed down due to the cat's claws being stuck or something equivalent into its rivals flesh. Of course, they still make formidable weapons, and felines can afterall use all eighteen of their claws as weapons whereas bears are limited to ten!

As for your statements regarding paw swipes, generally, bears will kill large prey by attempting to control the head of the animal, and than use their jaws to attack the throat. However, they have been known to kill large prey with a clout.

[brobear]

Wild Guide - Bears by Charles Fergus.

Grizzly Bear ( Ursus arctos )... When naturalist Terry Domico photographed a large male that researchers had caught in a leg snare, he watched the bruin vent its frustration on a 4-inch-diameter pine, snapping it off with a single bite. The bear has also chewed through several 6-and-8-inch-diameter trees nearby.

A grizzly bear's head is large. Its face has a "dished," or concave, appearance, with the muzzle ending in a broad, upturned snout. The grizzly possesses massive forelegs and a huge chest. A hump of muscle between the front shoulders provides power to the forelegs, for digging out food or excavating dens. A grizzly's front claws - digging tools par excellence - are longer than its rear claws and may be 3 to 4.5 inches or more in length. The claws are usually pale in color. If a bear's claws are prominent enough that you can see them while the bear is walking, you are probably looking at a grizzly rather than a brown-phase black bear. The rear track of a big grizzly can be 14 inches long and 8 inches wide.

[brobear]

cchspredatorcomparison.blogspot.com/2012/05/bite-force-grizzly-bear.html

Bite force: Grizzly bear

As I expected the grizzly bear had the largest bite force of the three predators. its bite force is equal to 8,000,000 Pascals or 1,160,302 pound-force/square inch [lbf/in squared]. this is enough pressure to crush a bowling ball. probably due to their large heads and muscles located there. even though they do not hunt for dear or elk very often they do fish for most of their meals and the powerful bite prevents the fish from slipping away. it may also be used in aserting dominance between male bears when they fight over territory or a female.