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The "King" of the bears - comparison between the Polar bear and the Brown bear
The "King" of the bears - comparison between the Polar bear and the Brown bear
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The "King" of the bears - comparison between the Polar bear and the Brown bear
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Size isn't everything...
http://www.nwf.org/News-and-Magazines/Na...n-Ice.aspx Aklak vs. Nanook: A Tale of Two Bears Like most scientists, the Inuit view Aklak, the grizzly bear, and Nanook, the polar bear, as two very different creatures. Their traditional tales of polar bears almost always portray these animals as powerful, keen-witted and worthy of great esteem. The grizzly, on the other hand, is seen as a more sinister beast, one that is likely to charge unexpectedly in an explosive manner. Some biologists might agree with that assessment, citing evidence that barren ground grizzlies appear to be more aggressive than grizzlies living farther south. One explanation, they say, could be that northern grizzlies evolved in a treeless world where there's no place to hide, so threatening one's opponent may make far more sense than fleeing. Whatever the reason, bear biologist Andrew Derocher says he is "a lot more comfortable capturing a big polar bear on the sea ice than a small grizzly on land. Grizzlies tend to react much more aggressively. It can be very unnerving." 
What was the largest brown bear weighted by scientists?
Regarding the polar bear, the largest polar bear weighted by scientists (that I'm aware of) was this one : ''Biologists, for example, rarely give names to the animals they handle, but one polar bear that Stenhouse and Nick Lunn caught on Southampton Island in 1985 was so big and burly — he weighed in at 810 kilograms (1,800 pounds) — that they nicknamed him "Stan." Stenhouse keeps a picture of "Stan" on the wall of his office in Hinton.'' source : A lifetime of bears: Canadian biologist in awe of the clever, powerful — and vulnerable — creatures (page 5)
I'm not sure who weighed the 1,656 pound Kodiak bear. But, in the wild, the brown bear cannot compete with the polar bear in a contest of size. Environment and food availability is the key. Put coastal brown bears on a diet of protein-rich blubber and you will have polar-sized grizzlies.
If someone was to draw-up a family tree of Ursus arctos ( I wish someone would ), that family tree would be incomplete without the polar bear. Ursus maritimus is genetically a brown bear, although one of great change due to a drastically different life-style. The mere fact that the polar exists speaks volumes for the adaptability of the grizzly. In my opinion - such as it is - the grizzly ( Ursus arctos ) is the king of the bears including the polar bear, even though he is classified under a different name - Ursus maritimus.
Melursus theobaldi was an ancestral bear intermediate between the grizzly and the sloth bear. This clearly explains why the sloth bear does not scurry up a tree as he is fully capable of doing. He inherited the grizzly's courage and aggressive behavior.
The fact that a group of grizzlies conquered the tropical environment of India where he adapted and evolved into the sloth bear bears witness to the grizzly bear's incredible survival skills. Just as that other group of grizzlies which conquered the far arctic to evolve into the huge polar bears. The grizzly ( Ursus arctos ) is clearly the King of Bears. He survived in Europe when the giant cave bears became extinct. He survived in North America when the giant short-faced bears became extinct. 
What is the full study for the chart below?
 *This image is copyright of its original author As I got it from a poster called "vodmeister" on new Carnivora here... carnivora.net/showthread.php?tid=4271&pid=26185#pid26185 Also according to this chart, polar bear is the largest and always the largest extant bear..  (12-05-2018, 06:49 PM)Panther Wrote: What is the full study for the chart below? This is the citation: Schwartz, C. C., S. D. Miller, and M.A. Haroldson. 2003. Grizzly bear. Pages 556-586 in G. A. Feldhamer, B. C. Thompson, and J. A. Chapman, editors. Wild Mammals of North America: Biology, Management, and Conservation. Second edition. Johns Hopkins University Press, Baltimore, Maryland, USA.  *This image is copyright of its original author
(12-12-2018, 09:57 PM)GuateGojira Wrote:True, but that book doesn´t give answers when those bears were weighed and either no information about age range. So an example about a chart with a lot of information and still difficult to make big conclusions. It is kind of frustrating how often that same problem occurs. I read that part of that book some time ago, but again more creating questions than giving answers :)(12-05-2018, 06:49 PM)Panther Wrote: What is the full study for the chart below? I edited a little bit, I had written before weight range when I meant age range of weighed bears :) (12-12-2018, 09:57 PM)GuateGojira Wrote: This is the citation: Schwartz, C. C., S. D. Miller, and M.A. Haroldson. 2003. Grizzly bear. Pages 556-586 in G. A. Feldhamer, B. C. Thompson, and J. A. Chapman, editors. Wild Mammals of North America: Biology, Management, and Conservation. Second edition. Johns Hopkins University Press, Baltimore, Maryland, USA. Thanks for the information, Guate..
Your chart does NOT show male Kodiak bear weights along with age of bears, number of bears for each weight, and season weights obtained.
(12-13-2018, 06:04 PM)GuateGojira Wrote: @Shadow I think that you would prefer a table like this:Yes, that gives good information and gives justice to bears and how they grow. If chart is like 1 years old, 2 years old, adults.... it is just too simplified and very difficult to get real picture about situation. It is just like you said about tigers. At some point animals mature enough to breed and then at some point it is ok to say, that physically full grown what comes to skeleton etc. Then only relevant variable is weight. Of course for majority of people rough estimations are just ok and it doesn´t matter to them really what bear is the biggest. But then again if we want to really find out in fair way, that how it is in reality, charts should be made in fair way so, that comparisons would be without too much room for speculation. We have now some charts suggesting that Alaskan coastal bears at least in some areas might be heavier, than Kodiak bears. Then again vast majority of biggest hunted bears happen to be Kodiak bears. They take always skulls of hunted bears so, that those can be measured. 17 out of 20 biggest ones are Kodiaks. Also heaviest know bears, which have been weight relatively reliable, are Kodiaks. Even in that one chart which panther shared, biggest individual male bear was Kodiak bear and with huge difference to biggest from Alaska peninsula weighing about 170 kg (!!!) more, that was over 600 kg bear and biggest from coast wasn´t even 450 kg. I hope, that good information could be found more, if not now, hopefully in future. I don´t care which one is bigger, those are all brown bears. But if some other bear is bigger, why all trophy hunters are so eager to go hunting to Kodiak islands in hope to get a "monster"? Statistics are always interesting, but I think, that it is just fair to demand certain quality too taking account qualities of species when making those. (12-13-2018, 06:04 PM)GuateGojira Wrote: @Shadow I think that you would prefer a table like this:I noticed something now, when I looked your posting again, which I didn´t notice before. But here is what I noticed and it was quite interesting and also proving how easy it is to make charts giving possible a very wrong picture about situation. Here is attached chart, which panther posted and where is given information like Alaskan peninsula bears would be clearly heavier, than Kodiak island bears. But when comparing these charts I noticed, that information in chart posted by panther is actually based to chart posted here by you and earlier by brotherbear.... And now we get to interesting part. In "panther" chart there are mentioned 10 Kodiak bears to get average weight to bears 6+ years. Then representing Alaskan peninsula there are only 5 specimens 9+ years!!! So all bears at least 9 years old, which is not a meaningless detail, when from this other chart we can see, that comparison group of Kodiaks are at maximum 9 years old, 2 are 6 years old, 3 are 7 years old and then 5 are 8 years old. That is how I understand that chart. Or oldest max 9 years old. This is very strange comparison to make it like that, when there are 5 Alaskan peninsula bears 9+ years old. If we calculate Kodiak bear 8-9 years old where we have as big (small) comparison group, what happens. Suddenly we have figures, where Kodiaks have average weight 379 kg and Alaskan peninsula bears 389 kg. So difference is 10 kg and here we have to remember again, that Alaskan peninsula bears in this group can be assumed to be older. So actually when we make this comparison in most fair possible way considering information what we can use, there is practically same average weights between these bears. We have to remember, that these bears gain weight a year by year also after age of 9 years even though skeleton is practically as big as it can be. It could be, that if there would have been 2 older Kodiaks, that their average weight had been bigger after all. My conclusion is, that with this information it is not possible to say which subspecies has bigger average weight. But when looking at all information, what I have seen I assume, that it is after all Kodiak bear most probably. I think like that because local officials even today say, that Kodiaks are biggest bears there and vast majority of known "monster sized" bears are Kodiaks. And there has to be reason why trophy hunters are so eager to get license to hunt especially at Kodiak islands. I can be wrong, but with known facts about bears and looking at these charts I dare to say, that not all statistics, even when printed at books are necessary accurate. There was time, when Guinness book of records claimed, that great white shark can be 12 meters long... I have read that specific book myself. Today we know better 
Shadow Wrote:I noticed something now, when I looked your posting again, which I didn´t notice before. But here is what I noticed and it was quite interesting and also proving how easy it is to make charts giving possible a very wrong picture about situation. Well actually, the chart you attached, which I posted here earlier isn't my source or back up. I fairly disagreed with it in the discussion with @ As for the weight of 389kgs claimed for Alaska peninsula brown bears is based on Just 5 post-prime specimens. And the other study I provided where they gave 700lbs average, they showed average of 357kgs(787lbs) for Alaska peninsula brown bears based on 21 specimens. Which is more reliable and meaningful than the previous chart claiming '389kgs' figure. The same problem with the chart posted by brotherbear. It was just based on 5 prime specimens. The number is too low to consider. Anyways, I found the link for the study of the following chart...  *This image is copyright of its original author Source: https://www.researchgate.net/publication/284678859_Brown_bear However, this study doesn't mentioned the ages of bears in the study. But we can get it if we use logical thinking. It gave some interesting points, and corrects our claims. From the study... "Size and Weight. Size varies greatly across the North American range, among sex and age classes of bears, and seasonally. Body masses from various populations are reviewed in the Interagency Grizzly Bear compendium (LeFranc et al. 1987) and supplemented with additional information (McLellan 1994). These records illustrate variation in body mass among populations (Table 26.1). Brown bears occupying coastal habitats of Alaska and British Columbia are the largest representative of the species in North America. Bears from coastal Alaska with access to salmon are the heaviest. For example, males from the Alaska Peninsula (Miller and Sellers 1992) average 357 kg, whereas males from the Yukon (Pearson 1975) average 145 kg. Females from the same areas average 226 and 98 kg, respectively. Popular literature often sensationalizes the “1000-pound bear.” Although brown bears have been documented to reach and exceed this weight (Craighead and Mitchell 1982), most are smaller. Mass in bears is related to diet (Hilderbrand et al. 1999a)." So according to this study, it was considered that Alaska peninsula brown bears are the largest species of Brown bears. Also on other hand it seems the 9 year old Brown bear is reaching it's full size in summer according to this chart (from the same study). It looks different for females.  *This image is copyright of its original author And the following quote gave different age for sexual maturity in male brown bears from Alaska... "Male Reproductive Characteristics. White et al. (1998) provide an excellent review of the reproductive characteristics of male grizzly bears. Based upon presence or absence of spermatozoa in the lumen of the seminiferous tubules, mean age of sexual maturity in a sample 20 grizzly bears from the continental Unites States was 5.5 years (White et al. 1998). The youngest bear with fully-formed spermatozoa was 3.5 years old and killed in July. Only 1 of 11 bears that were ≤4.5 years of age had spermatozoa, whereas 8 of 9 bears ≥5.5 years of age did (White et al. 1998). Erickson et al. (1968) reported spermatozoa in seminiferous tubules of brown bears in Alaska at 4.5 years of age, whereas Pearson (1975) reported them in bears 5-7 years of age." So according to this adult male brown bears from Alaska reach sexual maturity half year later than the grizzlies (inland population) of united states. And I already explained to @ So, they're older than 6+ individuals means 7+(or 8) individuals. Although, i don't really think a 8 year old male Brown bear is not adult. The calculation is alright, both based on 10 specimens. Believe me. So, I really don't think 9 year old male Kodiak bears aren't gonna surpass 800lbs mark on average. But of course individuals vary, especially in Alaskan Brown bears where they can pack more fat throughout their lives... (12-14-2018, 12:41 AM)Panther Wrote:Shadow Wrote:I noticed something now, when I looked your posting again, which I didn´t notice before. But here is what I noticed and it was quite interesting and also proving how easy it is to make charts giving possible a very wrong picture about situation. Quote: "So, they're older than 6+ individuals means 7+(or 8) individuals. Although, i don't really think a 8 year old male Brown bear is not adult. The calculation is alright, both based on 10 specimens. Believe me. So, I really don't think 9 year old male Kodiak bears aren't gonna surpass 800lbs mark on average. But of course individuals vary, especially in Alaskan Brown bears where they can pack more fat throughout their lives..." My last posting here was exactly about this part of your message. I disagree with you and I explained why in my posting. I leave it up to others to consider which one is giving more reasonable opinion and explanation here. I have nothing to change to my posting at this point, I wrote about my observations and gave reasoning. I know this other chart in your posting here and it has many problems too as it is explained in that chart itself and there is warning to be cautious in making comparisons based on that. Alone it should tell to anyone, that not making too big conclusions based on it. Still writers of that book write based on that, that bears on Alaskan peninsula are biggest :) I find it quite odd and it raises a lot of questions how credible that book is what comes to that claim, especially when there is other research giving so different results. Then again you say: "Also on other hand it seems the 9 year old Brown bear is reaching it's full size in summer according to this chart ..." Difficult to understand, that what on earth you are trying to say with that. 9 year old bear as a bear in any age is light in spring and after breeding time if sexually mature and then heavy in late autumn. 9-10 years old brown bear can be considered as fully grown even though it can continue up to 11 years and if I remember right even to 14 years old sometimes. But it is quite common agreement, that bear aged 9-10 years old can be considered as fully grown, even though they gain more weight after that too. |
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