There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
Skull sizes, body lengths/widths/girths/heights, and body weights will be compared between all species and genus of bears, from the earliest one (Ursavus) to all the modern ones.
II. Prey Habits
Prey types and sizes of all these bears will be compared (e.g Agriotherium with ancient proboscideans, polar bears with walruses, brown bears with unglates...), how often they hunt these prey, how often they target the larger or smaller prey.
Hunting tactics will also be compared between all the bears.
III. Competition with Other Carnivores
What are all the bear species' relations to other felids, ursids, canids, amphycyonids, and any other known, prehistoric carnivore? Were any of them dominant predators or were they lower in the feeding chain?
In regards to the "prey category" I'd have to say the polar bear. Even if we were to compare prey of each species of bear, non solely survive off meat/blubber like the polar. This forces polar bears to tangle with prey much more often, add that to the fact that they must search endlessly through the harshest terrain imaginable to find the prey. They can't afford to be choosy and that probably means taking much more risk.
10-26-2016, 08:46 PM( This post was last modified: 10-26-2016, 08:46 PM by Polar )
(10-26-2016, 07:32 PM)Pckts Wrote: In regards to the "prey category" I'd have to say the polar bear. Even if we were to compare prey of each species of bear, non solely survive off meat/blubber like the polar. This forces polar bears to tangle with prey much more often, add that to the fact that they must search endlessly through the harshest terrain imaginable to find the prey. They can't afford to be choosy and that probably means taking much more risk.
Agreed, both the polar bear and Agriotherium would be regarded as my two picks.
In relation to section II of the introduction, Agriotherium simply was not only a scavenger, but was also a big game hunter of the gigantic, ancient proboscideans (Deinotherium), and at the same time, competed with carnivore-like creatures such as Megistotherium. That is a big feat in itself.
I think Ursus Arctos (in Carnivora) once showed a document that proved Agriotherium had the largest jaw stress capacity out of any other ursid (possibly equal to Giant Panda). Does any one have this by any chance?
Polar bears also hunt the toughest prey on this planet which includes large bull walruses (which can take hours to kill) and, on very rare occasion, small whales.
In relation to section I, both are the two largest bears on average, with the exception of Arctotherium. However, these bears manage to keep a normal "bear" structure (robust) while that of the Arctotherium resembles more of a "camel".
I don't know if you can say a bull walrus is more or less dangerous than a bull moose or bison, but the rarity in which the ladder are taken compared to walrus being preyed upon more regularly is an advantage for the polar bear. But polar bears also take whales that are pretty much stranded, while it is a feat of strength to hoist them out of water I don't think it's an exceptionally dangerous proposition.
10-26-2016, 09:10 PM( This post was last modified: 10-26-2016, 09:12 PM by Polar )
A bull walrus may not be as dangerous agility-wise as a bull bison/gaur/buffalo, but I say it is the hardest because it can swim out of the polar bear's reach into the water without any warning, and the bear wouldn't be able to follow it. Hard work wasted. Not to mention the multiple layers of fat and tough skin and its agility, which is often underrated.
As for the latter bovines, a tiger or lion can always see (or smell) them since they are in the same plane. With walruses, though, it is completely the opposite.
It has many weapons in its arsenal but it's hard to measure ones adaption to another's. Each of the mentioned animals have many tools in their tool box in which they rely on.
10-26-2016, 09:28 PM( This post was last modified: 10-26-2016, 09:35 PM by Polar )
@Majingilane,
I would also agree with your desire of the brown bear as king, only under section III, though. Note that adaptability falls under section III. Unlike many other carnivores such as machairodonts, felines, or other ursids, brown bears:
-Weren't as big, and thus didn't require much of the nutrients that larger carnivores needed (useful for hyper-competition, where prey famine starts to occur).
-Hibernated just like the black bear did, so it didn't have possible risk of starvation or injury like other carnivores during those months.
-Have a more intimidating, "bully-like" aggressive behavior which gave them more prey to steal off of.
But in terms of the ability to achieve maximum size (and higher average size), and to regularly kill prey (both large and small), the polar bear and Agriotherium takes the bait. Although, some large modern brown bears (and prehistoric ones) hunt/hunted deer and large bovines, they don't do it on a regular basis. Most were omnivorous or scavenged. Only the exceptionally large brown bears regularly took meat as their primary source of food.
(10-27-2016, 12:27 AM)Kingtheropod Wrote: You are forgetting about Arctotherium
In relation to section I, Arctotherium might have been slightly more robust (and quite heavier) than its North American counterpart, but on a pound-for-pound basis, both Agriotherium and the polar bear/Pleistocene Polar Bear are more robust (shoulder width vs body length).
Also, using this "robust" argument in favor of the brown bear will fail because both Agriotherium and the polar bear are at least twice the weight of an average brown bear today.
This means that the latter two may be more effective in terms of grappling than Arctotherium, and thus more able to defeat Arctotherium in terms of direct competition (if they both lived at same conditions). Arctotherium isn't that much heavier than Agriotherium and Pleistocene Polar Bear on average.
Here I think the advantage goes to the Brown bear for "extant bears", they must compete with Wolf packs and possibly cougars although neither animal truly needs to "compete" with another carnivore once they are adults, they are usually the apex of their home.
If anything, the sloth bear has the highest competition with other carnivores.
Tigers, Dholes, Snakes, Wolves and leopards.
10-27-2016, 03:20 AM( This post was last modified: 10-27-2016, 03:25 AM by Polar )
(10-27-2016, 03:05 AM)Pckts Wrote: III. Competition with Other Carnivores
Here I think the advantage goes to the Brown bear for "extant bears", they must compete with Wolf packs and possibly cougars although neither animal truly needs to "compete" with another carnivore once they are adults, they are usually the apex of their home.
If anything, the sloth bear has the highest competition with other carnivores.
Tigers, Dholes, Snakes, Wolves and leopards.
Another important question under this section to ask is if these two bears are the dominant bears of other carnivores or other bears in their domains? Please note that this answer excludes humans and only includes carnivores in their natural setting.
Sloth bears do have extremely high competition with other carnivores, but in no apparent way are they the dominant carnivores of their domain. Tigers are much larger and they still prey on the bears. Same with sun bears. Barely any information hints at whether the spectacled bear is or isn't the dominant carnivore of its range.
On the other hand, different brown bear subspecies share different carnivores in their respective domains. Examples of this include: Ussuri Brown Bears vs Amur Tigers vs Amur Wolves, and North American Brown Bear subspecies vs Wolves vs Cougars. Brown bears in North America are much more dominant in their domains: countless examples of recorded evidence proves that they usually win encounters with wolves or cougars. With Siberian brown bears, however, it is not entirely conclusive whether the brown bear or the tiger is dominant. What could be said, though, is that extremely large brown bears are usually more dominant. Brown bears may only be completely dominant in some areas, but not so in others.
Add adaptability, and brown bears are good qualifiers for winning section III. They are only 'qualifiers' because polar bear reigns supreme in its own kingdom (with the rare exception of thieving brown bears) with no apparent competition. No competition for polar bear versus greater adaptability for brown bear? Your pick.
10-27-2016, 03:28 AM( This post was last modified: 10-27-2016, 03:29 AM by Pckts )
(10-27-2016, 03:20 AM)Polar Wrote:
(10-27-2016, 03:05 AM)Pckts Wrote: III. Competition with Other Carnivores
Here I think the advantage goes to the Brown bear for "extant bears", they must compete with Wolf packs and possibly cougars although neither animal truly needs to "compete" with another carnivore once they are adults, they are usually the apex of their home.
If anything, the sloth bear has the highest competition with other carnivores.
Tigers, Dholes, Snakes, Wolves and leopards.
Another important question under this section to ask is if these two bears are the dominant bears of other carnivores or other bears in their domains? Please note that this answer excludes humans and only includes carnivores in their natural setting.
Sloth bears do have extremely high competition with other carnivores, but in no apparent way are they the dominant carnivores of their domain. Tigers still prey on them. Same with sun bears. Barely any information hints at whether the spectacled bear is or isn't the dominant carnivore of its range.
On the other hand, different brown bear subspecies share different carnivores in their respective domains. Examples of this include: Ussuri Brown Bears vs Amur Tigers vs Amur Wolves, and North American Brown Bear subspecies vs Wolves vs Cougars. Brown bears in North America are much more dominant in their domains: countless examples of recorded evidence proves that they usually win encounters with wolves or cougars. With Siberian brown bears, however, it is not entirely conclusive whether the brown bear or the tiger is dominant. What could be said, though, is that extremely large brown bears are usually more dominant. Brown bears may only be completely dominant in some areas, but not so in others.
Add adaptability, and brown bears are good qualifiers for winning section III. They are only 'qualifiers' because polar bear reigns supreme in its own kingdom (with the exception of thieving brown bears) with no apparent competition. No competition for polar bear versus greater adaptability for brown bear? Your pick.
I didn't mean that Sloth were the dominant predator, since they aren't carnivorous, just that they probably have the most competition, like Ussuri Brown bears, they must compete with Tigers and wolves (not as formidable as Amur Wolves once were) and more.
The Ussuri Brown Bear has two serious competitors but their terrain is so sparse, their habitat so depleted and their competitors numbers are staggeringly low, the likely hood of them coming into contact with said competitors is probably far lower statistically.
At the end of the day, whatever bear needs to compete with a Tiger is going to have the advantage in this category. Nothing really can challenge it other than a Tiger in a Bears chosen Territory.
