Polar Bear - Kodiak Bear comparison

[tom]

Ok so this is basically a study of elbow, joint morphology of Bears as it relates to grappling ability. Initially I thought maybe this was scored on observing Bears in the wild. Even so the two are very close IMO and essentially equal. The rest of the Bears on that list are quite a separation from the top two it wold seem. Non-ursids are considerably way down on the scoring as is easy to understand. 

[tom]

I would also make a case for the difference in claws. While the Polar Bear claws are smaller, they are sharper with more of a pronounced hooked towards the end which in itself would lend itself for better grappling or holding or dragging of its prey. Not to mention better traction on the ice.

Note the Polar Bear claw 2nd from the left. Grizzly and Kodiak Bear are 3rd and 4th respectfully.

[King Kodiak]

Yes, to be fair, the study just has "brown bears", not specifically Kodiak bears. But in a general sense yes, the polar bear should be a better grappler and this should be obvious as it grapples large aquatic prey.

On a side note, jaguars have a lower PC2-Value than lions so in general its a better grappler:

Jaguar: -1.713
Lion: -0.531

But that does not mean that a jaguar would beat a lion in a straight grappling match because the lion is normally double the weight of a jaguar. But if the lion does not have a weight advantage, then the jaguar would definitely win the grappling match as according to this study it has better dexterity/flexibility

[brobear]

Sept 2, 2020 14:01:41 GMT -5 King Kodiak said:

Yes, the polar bear has a lower PC2-Value, therefore its a better grappler. Obviously, polar bears are adapted to grappling down large aquatic prey. Its not about moving huge rocks.

It's all about how they use their arms and paws in their normal everyday lives. Sure, polar bears are known to occasionally take down huge prey such as a walrus cow or even a beluga. But mostly they feed on seals and beached whales. Long distance walking and swimming are their main function. Perhaps climbing on ice also contributes. In any case; the difference between the grappling ability of the polar bear and his brown cousin appear to be minimal. 

[King Kodiak]

Oh yeah definitely. Swimming would definitely make the polar bear have more dexterity/flexibility on its forearms.

[brobear]

Oct 20, 2021 2:02:46 GMT -5 theundertaker45 said:

This comparison picture clearly shows us that no other living bear can match the size of the biggest polar bears. 

[tom]

I take it these are average height measurements? The height difference is not huge and the largest Kodiaks IMO can rival all but the Largest of Polar Bears.

Curious, the Polar Bear is obviously longer (length), how much longer?

[brobear]

Oct 20, 2021 8:29:06 GMT -5 tom said:

I take it these are average height measurements? The height difference is not huge and the largest Kodiaks IMO can rival all but the Largest of Polar Bears.

Curious, the Polar Bear is obviously longer (length), how much longer?

'Taker gives this comparison at maximum-sized individuals. Considering that the kodiak can stand bipedal at over 9 feet tall, pushing close to 10 feet, ( Bart was a maximum-sized Kodiak bear ) and a polar bear, a really huge one, can stand at 11 feet tall, then my guess would be that the length difference would likely be roughly one-foot ( specualtion ).

[brobear]

Shoulder Height: 
 
152 centimeters is equal to 59.84 inches. ( 4 feet 11.88 inches ) rounded off - 5 feet.

160 centimeters is equal to 62.99 inches. ( 5 feet 2.99 inches ) rounded off - 5 feet 3 inches.

[horribilis]

Morphological forelimb comparison between polar bear and brown bear :

Shoulder Hump :

The hump is where a mass of muscles attach to the bear's backbone and give the bear additional strength for digging.

U.Maritimus : Absent

U.Arctos : Present

Edge : U.Arctos


Scapula Shape Index:

It's scapula width/length ratio.Higher score indicates greater muscle attachement on the shoulder joint as well as greater ability to make certain movements like full-functional upper extremity movement including protraction,retraction,elevation,depression,upward rotation,and downward rotation all else being equal.

U.Maritimus : 89,25%

U.Arctos : 86,9%

Edge : U.Maritimus


API:

Acromion process length/scapula length. Higher score in this ratio increases attachment for the deltoid muscle.

U.Maritimus : 21,15%

U.Arctos: 18,71%

Edge : U.Maritimus


SMI:

Deltopectoral crest length divided by humerus length. Higher score Displays greater mechanical advantage of deltoid and pectoral muscles at the shoulder joint.

U.Maritimus : 69,26%

U.Arctos : 71,80%

Edge : U.Arctos


Forelimb Proportion Index:

Scapula length divided by Forelimb length. Higher score Indicates exertion of greater force from the Forelimb .

U.Maritimus : 30,14%

U.Arctos : 31,50%

Edge : U.Arctos


HRI :

It is humerus mediolateral diameter at mid-shaft/humerus length.Robust forelimb bones protect the animal from violent stresses during grappling.

U.Maritimus : 9,8%

U.Arctos : 10,8%

Edge : U.Arctos


HRI2 :

It is humerus anteroposterior diameter at mid-shaft/humerus length. Robust forelimb bones protect the animal from violent stresses during grappling.

U.Maritimus : 12,13%

U.Arctos : 11,52%

Edge : U.Maritimus


HCMI :

It is Humeral circumference/articular length Often-used variable in analyses of bone strengths in locomotion. The higher the ratio is, the thicker the Humeral bone is.

U.Maritimus : 32,27%

U.Arctos : 33,69%

Edge : U.Arctos


HEI:

The HEI index measures the relative size of wrist stabilizing muscles and well as several grasping muscles in area which facilitate prey grasping. These muscles also likely help stability, pushing, and agility when legs are on ground.

U.Maritimus : 31,76%

U.Arctos : 29,97%

Edge : U.Maritimus


PC2 :

Scoring intermediate or low on PC2 are carnivorans that use their forelimbs to subdue,manipulate or excavate food items.Carnivorans scoring low on PC2, i.e. grapplers like felids, have relatively shallow trochlear furrows and relatively large and distally-projecting medial trochlear flanges. These features provide extra stability against forces acting in a nonparasagittal plane.

U.Maritimus : -7,999

U.Arctos : -7,045

Edge : U.Maritimus


HTI :

It's Humeral trochlear length/Humeral length. Higher score increases muscle attachement on the elbow joint and allows for more ulnohumeral flexion and extension.

U.Maritimus : 21,84%

U.Arctos : 21,29%

Edge : U.Maritimus


Brachial index :

This measures radius length/humerus length. Lower scores in this ratio indicate greater forelimb muscle mechanical advantage and results in stronger muscles all else being equal.

U.Maritimus : 84,09%

U.Arctos : 85,63%

Edge : U.Maritimus


Brachial index 2 :

This measures ulna length/humerus length. Lower scores in this ratio indicate greater forelimb muscle mechanical advantage and results in stronger muscles all else being equal.

U.Maritimus : 101,08%

U.Arctos : 95,75%

Edge : U.Arctos


Forelimb Proportion Index 2 :

Length of proximal forelimb relative to length of distal forelimb ((Scapula length + Humerus length)/(Radius length + Metacarpal length)). Higher score Indicates greater degree of morphological specialization for producing large out-forces in the forelimb.

U.Maritimus : 149,26%

U.Arctos : 154,22%

Edge : U.Arctos


RRI :

This measures radius mediolateral diameter at midshaft divided by radius length. As mentioned above for humerus robusticity, a robust radius resists stresses on bones during fights and increases resistance to bites to the forelimb.

U.Maritimus : 10,56%

U.Arctos : 10,46%

Edge : U.Maritimus


RRI2 :

This measures radius anteroposterior diameter at midshaft divided by radius length. As mentioned above for humerus robusticity, a robust radius resists stresses on bones during fights and increases resistance to bites to the forelimb.

U.Maritimus : 6%

U.Arctos : 6,09%

Edge : U.Arctos

RRI3 :

This measures radius mediolateral diameter at midshaft divided by radius length. As mentioned above for humerus robusticity,A relatively high score would be expected in species with limb bones that are built to withstand relatively high stresses either during locomotion or prey capture.

U.Maritimus : 16,5%

U.Arctos : 16,5%

Edge : Draw

URI:

It is ulna mediolateral diameter at mid-shaft/humerus length. As mentioned above for humerus and radius robusticity, Robust forelimb bones protect the animal from violent stresses during grappling.

U.Maritimus : 6,11%

U.Arctos : 6,01%

Edge : U.Maritimus

URI2:


This measures ulna anteroposterior diameter at midshaft divided by ulna length. As mentioned above for humerus and radius robusticity, a robust ulna resists stresses on bones during fights and increases resistance to bites to the forelimb.

U.Maritimus : 12,05%

U.Arctos : 10,5%

Edge : U.Maritimus

URI3 :

This measures radius mediolateral diameter at midshaft divided by radius length. As mentioned above for humerus and radius robusticity,A relatively high score would be expected in species with limb bones that are built to withstand relatively high stresses either during locomotion or prey capture.

U.Maritimus : 18,16%

U.Arctos : 16,51%

Edge : U.Maritimus


OI:

This metrics estimates tricep muscle strength. High values indicate greater ability to push with arms all else being equal. This helps a grappling cat hold prey and also helps a canid push and knock down an opponent. In addition, higher values may indicate greater stability and ability to change direction in a fight as well as greater relative mechanical advantage of the triceps brachii and dorsoepitrochlearis muscles used in elbow extension.

U.Maritimus : 19,57%

U.Arctos : 18,75%

Edge : U.Maritimus



MANUS:

Manus digit 3 proximal phalanx length divided by metacarpal 3 length.Higher score Indicates greater relative proportions of proximal and distal elements of the manus and size of the palmar surface.

U.Maritimus : 49,19%

U.Arctos: 54,83%

Edge : U.Arctos


CLAW:

Manus digit three terminal phalanx length divided by pes digit three terminal phalanx. Higher score is to be expected in species whose claws are more capable of breaking soil.

U.Maritimus : 100,03%

U.Arctos : 135,59%

Edge : U.Arctos

Throughout the centuries, the lion has been popularly known as the king of all terrestrial predatory animals. While certainly impressive enough in its own right, modern research has demonstrated that bears tend to be more powerfully built than big cats including lions even on a proportional basis. The polar and brown bears are the biggest and strongest extant representatives of the bear family and therefore both deserve the title more than lions do. Yet, only one can get the number 1 spot. In terms of size, the Polar Bear seems to be the likely candidate since with a weight range of 400-600 kg , it's on average bigger than even the largest Brown Bear populations which average around 360 kg.

However, if we want to compare the two on a pound per pound basis, both bears have equally thick radii .However, Ursus Arctos has a shoulder Hump,relatively larger scapulae, deltopectoral crests, thicker Humeral shafts, shorter ulnae, bigger paws, deadlier claws and the ability to produce more force as evident from its Forelimb Proportions while Ursus Maritimus has stronger thicker scapulae, larger acromion processes,epicondyles,trochleas,olecrana,shorter radii and thicker ulnae. Each bear has its own advantages in this matchup but Brown Bears bite harder than Polar Bears of equal size as evident from their respective BFQ scores and have mostly dominated Polar Bears weighing twice as much during interspecific competition for carcasses.

Therefore, Ursus Arctos rightfully earns the title of King of all terrestrial predators while Ursus Maritimus gets the second place !


Credits to Ghostface Killah for making this comparison .Here's the original source - justpaste.it/2pogx

[OldGreenGrolar]

horribilis , that is a good comparison above.

[brobear]

Apr 24, 2022 10:32:01 GMT -5 OldGreenGrolar said:

horribilis , that is a good comparison above.

Agreed; outstanding information.

[brobear]

Who has the biggest arms?
Who has the biggest paws?

[OldGreenGrolar]

Jan 28, 2023 6:48:15 GMT -5 brobear said:

Who has the biggest arms?
Who has the biggest paws?

I think the polar bear from Foxe Basin has the biggest arms overall. Kodiak bears have the biggest paws.

Another comparison created by Taker:

[brobear]

Quote; "I think the polar bear from Foxe Basin has the biggest arms overall. Kodiak bears have the biggest paws."

The Foxe Basin polar bear absolutely has the biggest arms because he is by far the biggest living bear. But, at equal HBL, who has the biggest arms and paws?
For the polar bear, his paws are swimming paddles and snow shoes. If you come across any forelimb and/or paw measurements; please post that info.

[OldGreenGrolar]

Feb 12, 2023 4:02:02 GMT -5 brobear said:

Quote; "I think the polar bear from Foxe Basin has the biggest arms overall. Kodiak bears have the biggest paws."

The Foxe Basin polar bear absolutely has the biggest arms because he is by far the biggest living bear. But, at equal HBL, who has the biggest arms and paws?
For the polar bear, his paws are swimming paddles and snow shoes. If you come across any forelimb and/or paw measurements; please post that info.

Average male polar bear:
Tracks: A polar bears forepaw is approximately 5 ¾ inches long and 9 inches wide while the hindpaw usually measures 13 inches long and 9 inches wide. The toes form an arc similar to a black bear’s track. A polar bear’s track is generally only visible in soft snow or mud and may show fringed edges due to the hair on the paw (Brown 1993, p 76). The bottom of the paw is completely covered with fur. The claws are black, short and stocky and are usually not visible in the track (Stirling and Guravich 1990, p 39).



bear.org/polar-bear-facts/



An average of 9 inch could mean 22.5cm paw width. The average male polar bear’s paw width is slightly wider than that of the largest male Ussuri brown bear and male Kamkatcha brown bear.

Large male polar bear:
Polar bears have large paws compared to body size, reaching 30 cm (12 in.) in diameter. The large paws of a polar bear act like snowshoes, spreading out the bear's weight as it moves over ice and snow.



seaworld.org/animals/all-about/polar-bear/characteristics/



The only brown bears with wider paws than a yellowish white bear would be the kodiak and peninsula Alaskan brown bear.



30cm is the widest paw width a male polar bear has achieved so far. Maybe Stan’s paws are much larger if 30cm is for the largest common male.

Large Peninsula Alaskan brown bear:

1954: Alaska peninsula brown bear hunting record, estimated to weigh 2200 lbs, 35 years old, front paw width of 13 inches (33 cm), skull scored 34 9/16 (not recognized by Boone and Crockett):





beargorillarealm.proboards.com/post/7972

The paws of the brown bear are quite large. The rear feet of adult bears have been found to typically measure 21 to 36 cm (8.3 to 14.2 in) long, while the forefeet tend to measure about 40% less in length. All four feet in average sized brown bears tend to be about 17.5 to 20 cm (6.9 to 7.9 in) in width. In large coastal or Kodiak bear males, the hindfoot may measure up to 40 cm (16 in) in length, 28.5 cm (11.2 in) in width, while outsized Kodiak bears having had confirmed measurements of up to 46 cm (18 in) along their rear foot. Brown bears are the only extant bears with a hump at the top of their shoulder, which are made entirely of muscle, this feature having developed presumably for imparting more force in digging, which is habitual during foraging for most bears of the species and also used heavily in den construction prior to hibernation.





www.inaturalist.org/guide_taxa/889098#:~:text=The%20paws%20of%20the%20brown,to%207.9%20in)%20in%20width.

When comparing the sources, it seems that a large male polar bear actually has slightly wider paws than a large kodiak and coastal brown bear (30 cm vs 28.5 cm). I have mistaken length for width . My apologies .

Outsized kodiaks might have 46 cm measurements in the rare foot not fore paw, I think Stan might actually have the widest paws. Not a surprise, polar bears need wider paws to walk on thin ice.

[brobear]

Excellent information OldGreenGrolar. Thumbs up.               
  
At size-parity, it appears to be a close contest, which is surprising to me. The forelimbs of a polar bear appear larger than those of a brown bear. Perhaps simply an optical illusion? 

[OldGreenGrolar]

Feb 12, 2023 9:38:17 GMT -5 brobear said:

Excellent information OldGreenGrolar. Thumbs up.               
  
At size-parity, it appears to be a close contest, which is surprising to me. The forelimbs of a polar bear appear larger than those of a brown bear. Perhaps simply an optical illusion? 

A bit of correction on my part. 28.5 cm for the Kodiak bear refers to the hind foot width. However, it is said that all four feet average in average brown bears is 17.5 cm to 20cm in paw width is less than the average width of the male polar bear which is 22.5cm.

Also the Peninsula Alaskan brown bear which has a 33cm paw width weighs 2200 pounds while a large polar bear (common weight) probably weighs 1540 pounds at most (30 cm paw width). Therefore, Stan and other exceptionally large male polar bears might have paw width that surpasses 33 cm (just my opinion).


Regarding forelimbs:

beargorillarealm.proboards.com/post/599/

The polar bear has denser bones than grizzlies (including the Peninsula Alaskan grizzly in my opinion) due to its more aquatic lifestyle explaining why it is a better grappler too. Since the Kodiak bear is a brown bear and terrestrial animal, the polar bear’s forearms might be slightly stronger but the kodiak has a stronger body overall.

Polar bears also have thicker fur but the brown bear’s shoulder hump probably balances it out.

[brobear]

Bone density comes from usage. Brown bears have dense bones because most of them live in a mountainous environment and all of them spend time digging. But the polar bear spends so much time swimming... pulling against water. All exercise helps build strong bones.
Example, active people who live in the mountains have stronger bones than those living on flat land. Another great reply OldGreenGrolar. 

[Deleted]

Oct 20, 2021 8:29:06 GMT -5 tom said:

I take it these are average height measurements? The height difference is not huge and the largest Kodiaks IMO can rival all but the Largest of Polar Bears.

Yes i agree.