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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)
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GuateGojira says: Sadly, these tables are the only information that we have and I think that we must respect and use it, as they are the results of hard work and time from scientists that try to present information usefull to all of us.
I have seen charts of Yellowstone grizzlies which had age, sex, and weights. Several specimens of each age. From this I could do my own averaging of 9+ year old male grizzlies. My average was much higher that what biologists were claiming as average adult male. It makes a difference; probably more than with many other animals.   (12-13-2018, 03:40 AM)brotherbear Wrote: I have seen charts of Yellowstone grizzlies which had age, sex, and weights. Several specimens of each age. From this I could do my own averaging of 9+ year old male grizzlies. My average was much higher that what biologists were claiming as average adult male. It makes a difference; probably more than with many other animals. That is correct, I think that the document with those especific sizes, weights and ages is "Size and growth patterns of the Yellowstone Grizzly bear" from Bonnie Blanchard. It would be interesting to see the original document of Dr Kucherenko about those bears that he measured and weighed in the Amur region, maybe he do separate them base in age or season, maybe not. Sadly the table that I keep came from an article from a Russian reporter that presented the data, but as the original webpage is lost, I can't corroborate this. Regarding the bears captured by modern scientists, I don't have more information apart from the table published by Dr Goodrich and his team and the article of Mr Suvorov.
Just to finish the bear-related conversation, remember these weights:
 *This image is copyright of its original author The largest of the two males captures in Sikhote Alin (235 kg) was a 8-10 years old male, below the average weight reported in the two previous tables (260-270 kg) but still a mature male. This may suggest that the sample presented by Dr Kucherenko, and probably also Dr Goodrich and his team, do take in count old mature males. But is just an assumption. 
KUCHERENKO
I saw the famous Kucherenko-table in an article written for hunters. American trophy hunters, to be precise. Based on what I read, I'd say it was written to encourage them to visit the Russian Far East. Hunters like size. The bigger, the better. For this reason, Kucherenko could have selected large individuals only. Recent research says adult males, like he said, really average 590-600 pounds in the Russian Far East, but the range most probably isn't as limited as in Kucherenko's table (260-320 kg. or 565-722 pounds). The table below, first posted by Warsaw in AVA, about the size of brown bears in the northeastern part of Russia could be more accurate. The sample is larger and the range is much more outspoken:  *This image is copyright of its original author I know the bears in the table do not quite belong to Ursus arctos lasiotus, but it has adult males only and in size they more or less compare to their relatives in the Russian Far East. Individual variation, as you can see, is very pronounced. Whereas some of them, at least weightwise, are within the predatory reach of male Amur tigers, the great majority is not. A few are very large. A good table should have distinctions between age classes, especially in large and long-lived mammals like brown bears. The table Guate today posted about averages in Kodiak brown bears clearly shows the outspoken differences between age classes. There are different ways to get to age classes. In the thread about male tigers and male brown bears in old AVA, I posted about a paper written by B.P. Zavatsky (1976). He studied skulls and teeth to get to age-based distinctions in brown bears: https://www.bearbiology.org/wp-content/uploads/2017/10/Zavatsky_Vol_3.pdf There's much more where this came from (the internet), including recent articles about skulls of brown bears in Bulgaria and Iran. Based on everything I read, I'd say that one has to distinguish between young adults (5-8), adults (9-12), mature adults (13-18) and old adults (> 18) in large brown bear subspecies like Kodiak bears. At the level of averages, the difference between the age groups is considerable. Like tigers, brown bears seem to keep on growing nearly all their life. Skulls of old bears nearly always are larger and heavier than those of younger individuals. Male Amur tigers involved in brown bears occasionally attack adolescent males, but I never read anything about tigers preying on young adult males, let alone adults and older males. This although young adult males are not much bigger than mature females. According to Kerley, male Amur tigers hunt female brown bears " ... up to the largest and healthiest (individuals) ... " (from her mail to Junglesprout in September 2011). Her observation was confirmed by others. The question is why they do not hunt young adult male brown bears similar in size and weight (150-200 kg. or 330-441 pounds). My guess is it could be a result of a combination of strength and disposition. In the Russian Far East, brown bears are known for their disposition. Pikunov said they're more dangerous than Amur tigers. As to posts about bears in this thread. I don't mind good info about bears, provided it's related to the Russian Far East. The reason is Amur tigers, brown bears and Himalayan black bears live in close proximity in southeastern Russia. Info about the way they interact is of interest, that is.
CARNIVORE SKULLS - IDENTIFICATION AND MEASUREMENT - FOR ECOLOGISTS (M.A. Adibi, Research, October 2016)
Talking about skulls. This is something I recently found: https://www.researchgate.net/profile/Mohammad_Ali_Adibi/publication/309320542_Carnivores_Skulls_-_Identification_and_Measurement_-_for_Ecologists/links/5809cf5a08ae1c98c253a84b/Carnivores-Skulls-Identification-and-Measurement-for-Ecologists.pdf Interesting read for those interested in skulls of carnivores. I'll also post the link in the cat anatomy thread. In order to avoid jumping from one thread to another, I decided to post it in this thread as well. 
12-14-2018, 06:43 PM
( This post was last modified: 12-14-2018, 08:17 PM by Shadow
Edit Reason: typos
)
(12-13-2018, 10:49 PM)peter Wrote: KUCHERENKO There was this part of your posting which was in a way especially interesting for me: "According to Kerley, male Amur tigers hunt female brown bears " ... up to the largest and healthiest (individuals) ... " (from her mail to Junglesprout in September 2011). Her observation was confirmed by others. The question is why they do not hunt young adult male brown bears similar in size and weight (150-200 kg. or 330-441 pounds). My guess is it could be a result of a combination of strength and disposition. In the Russian Far East, brown bears are known for their disposition. Pikunov said they're more dangerous than Amur tigers." Of course male bears can be aggressive in certain situations even though usually bears are towards humans pretty harmless. Anyway it is interesting if/when bears in Russian far east are known for their disposition. Does this concern all brown bears there or is this the matter among Ussuri brown bears living at same areas as tigers. Just thinking, that have Ussuri brown bears evolved to be more aggressive because have to deal with tigers. It sounds sensible, because that could be a way to minimize a risk for a fight with tiger. Of course if that concerns all brown bears from Ussuri area to Kamchatka peninsula, then looks to be some other reason, maybe they are just all "mental" :) It just is interesting to know if there are differences between brown bears living in "tiger areas" and other brown bears. Olga.boshoi also had interesting posting about brown bears and tigers recently in Bear and Big Cat interactions in the wild thread.. So now what I am thinking is, that is there partial expelling of bears at areas where tigers are. And this issue about male bear disposition at same area, could these things connect in some way and be pieces of puzzle giving more information about interactions between Ussuri brown bears and Amur tigers. Females and cubs going to outer regions of areas with higher tiger density and then leaving there less bears, but then again are those bears inside tiger areas then mostly more fierce male bears with attitude (alongside big size) keeping them safe from tiger attacks? One thing about bears which should be also remembered when thinking their movements. During breeding time male brown bears are very aggressive (from May to July, mostly on June). At that time female bears with cubs try usually to avoid them and leave areas where male bears. Reason is, that male brown bears can kill cubs in hope to make female bear again in heat. If male bear manages to kill cubs of a female bear, that female bear is soon ready to breed. Otherwise females aren´t eager to do that until former cubs are independent. So at that time of year there is movement among bears. Especially at June tigers are not only problem for female bears and cubs. There is even research indicating, that female bears with cubs move closer to human habitats during breeding time and avoiding in that way male bears which even at that time avoid humans. Quite interesting when thinking how animals can adapt their behavior.
Pioneers into the American West found highly aggressive grizzly bears. This is because of their long history in the Pleistocene of living among a multitude of very large aggressive predators. This is of course a theory I suppose; but one I certainly believe. The Amur brown bear is the last brown bear left on earth who has to deal with a super-preator - the tiger.
 (12-14-2018, 08:15 PM)brotherbear Wrote: Pioneers into the American West found highly aggressive grizzly bears. This is because of their long history in the Pleistocene of living among a multitude of very large aggressive predators. This is of course a theory I suppose; but one I certainly believe. The Amur brown bear is the last brown bear left on earth who has to deal with a super-preator - the tiger.Brown bear would trying to steal kill from tiger during the winter, as we know that some of the big male bear would usually searching food in winter but not choosing hibernation, they would steal or rob other carnivore's kills like wolf pack, in far east, brown bear would trying to steal kills from tiger and lynx usually during the cold winter season. 
One of the rare captures a wild bengal tiger in the snow. There aren't many pictures of bengal tigers in the snow except the once from bhutan/ Himalayas in which they can adapt well to live above 4,000 meters above sea level
 *This image is copyright of its original author  *This image is copyright of its original author  *This image is copyright of its original author
 (12-11-2018, 07:38 AM)peter Wrote: but they do seem different from one or two decades ago. Not long and tall, as their captive relatives (referring to Amur tigers in northwestern Europe), but stocky and robust. Are they developing a new model, or have sleeping genes been re-activated? Yes, this Amur tiger from the night video (second 42) looks quite robust somehow remind me Kaziranga tigers: https://www.youtube.com/watch?v=ph9u17PgyCg Probably in last decade Amurs are really getting a bit heavier, we need fresh scientific data. Title of the video below is: "Brown bear at the tiger's poste box". This skinny bear obviously is trying to out-smell the tiger's mark on the tree. Its not first camera-trap showing that tigers and bears try to out-smell each other living their marks on same trees. Its probably kind of competition between different predators in Ussuri forest, even some grew wolves join this game. (12-15-2018, 07:50 AM)Wolverine Wrote: Probably in last decade Amurs are really getting a bit heavier, we need fresh scientific data. I am agree, all the adult males captured by the Amur Tiger Programme weigh no less than 200 kg and the maximum, for the moment is 212 kg (recorded in the year 2011). This means that present males probably weight the same or even more! Sadly, I have visited the webpage of this Russian program and I can't found any email to contact them. 
(12-14-2018, 06:43 PM)Shadow Wrote:(12-13-2018, 10:49 PM)peter Wrote: KUCHERENKO THE SIBERIAN TIGER PROJECT (STP) The Siberian Tiger Project (STP), a joint effort of Russian and American biologists to get to more knowledge about Amur tigers, started in 1992. It has been a very productive effort in all respects: 1 - myths have been replaced by knowledge; 2 - there is much more interest in conservation in general; 3 - the number of tigers has grown considerably, and, last but not least, 4 - people seem prepared to make room for them and all their neighbours. If Pikunov's proposal to create two more reserves will be adopted and the new reserve in China is added, chances are the next generation also will be able to visit the only region on this planet where tigers and brown bears co-exist. A region unsurpassed for beauty as well. The effort in the Russian Far East is in many ways examplary. One can only hope the STP (and the Amur Tiger Programme) will continue for many more years. TIGERS AND BEARS BEFORE THE STP STARTED Before the STP started, the situation on tigers and bears was unclear. Based on everything I read published before 1992, I'd say that most thought that tigers only hunted bears in years when red deer and wild boars had migrated to greener pastures. Back then, it was also assumed they hunted most bears in winter. In spring, summer and autumn, tigers, when they hunted bears at all, preferred cubs. This assumption was based on a number of incidents in which tigers had been killed by brown bears. Although biologists agreed that an experienced tiger could surprise a largish bear, most assumed that brown bears were too dangerous to hunt. TIGERS AND BEARS IN THE FIRST TWO DECADES OF THE STP - ASSUMPTIONS CONFIRMED The documents published in the first two decades of the STP more or less confirm most assumptions discussed above. They also said that wild Amur tigers were quite a bit smaller than the alleged giants shot a century ago. Although the sample used to get to conclusions was small and polluted by 'problem tigers' and young adults, some biologists, like some of their collegues in India, used the results to underline their opinion on old hunting records in general. They concluded that most of the old records were a result of stretched skins, 11-inch tapes, inadequate scales, preferenced Maharajahs and myths. Brown bears, on the other hand, were as large as ever. There was also no question that they were able to displace tigers almost at will, they thought. Agreed, some male tigers had killed a few adult female brown bears, but they often had a significant advantage and their victory had come at a cost. One male had been quite severely wounded by the female he had killed after a 20-minute fight. THE INITIAL RESULTS - HEATED DEBATES I'm not saying they reminded me of Clyde Beatty, but most statements discussed in the previous paragraph had to be, ehh, 'refined' later. That was after they had resulted in heated debates between those interested in tigers and bears. Unexpectedly, quite a few of these debates proved to be productive in that posters more or less concluded the tiger and bear situation could be a bit more complicated than some biologists assumed. They were quite close. TIGERS AND BEARS IN THE LAST DECADE OF THE STP - MYTHS DEBUNKED In the last years, the pendulum shifted once again. Based on the documents published between, say, 2009-2017, it seems safe to conclude that 1) tigers hunt bears, including brown bears, more often than was assumed. 2) So much so, that they are as important as red deer and wild boars in some regions and seasons. 3) Tigers do not hunt bears in winter, but in spring, summer and autumn. 4) Although male tigers in particular hunt bears, tigresses have been active in that department as well. 5) Tigers seem to prefer quite large bears " ... up to the size of the healtiest and largest female ... " (L. Kerley, 2011). 6) The pressure on female brown bears is so high, that they left districts inhabited by male tigers interested in bears. 7) Recent research confirms that brown bears displace tigresses, but it doesn't happen as often as many assumed. 8) Male tigers are not displaced by male brown bears. At least, not in the reserve monitored by biologists in the period 1992-2013. MYTHS AND RESEARCH - A FEW CONCLUSIONS As some stated some years ago, research nearly always debunks myths. Not quite in the direction they initially thought, but debunked they were. The conclusion is that research is the best way to get to knowledge. On the present situation. Another conclusion is that it takes time to get to correct conclusions. Things often are a bit different than many initially assume. Time, therefore, is a factor to consider. Finally, one has to assume that things can change over time. Mammals can, and often will, adapt their behavior over time. Same for tigers and bears in the RFE. MALE TIGERS AND MALE BROWN BEARS - PROPOSAL FOR A DEBATE One conclusion that hasn't been debunked is that tigers do not hunt adult male brown bears. The only male brown bear partly consumed by a male tiger in the reserve monitored in the period 1992-2013 had been killed by another male brown bear. It's not too difficult to find a good reason: male brown bears are as large as male tigers or larger (a); they are very agile for their size (b) and they often have a significant weight advantage ©. At roughly similar size, they are more robust than male tigers. As a result, they are very difficult to kill (d). One wonders why that advantage isn't used to displace male tigers. We also never heard anything about fights between adult males. What are we missing? The only way to get to an answer is to discuss male tigers and male brown bears once again. I'll start it with two posts I printed about ten years ago. Their were posted by 'Big Bonns', a bear poster from old AVA. One has info from a trainer he interviewed. In the other, Dmitry Pikunov, an authority on tigers and brown bears in the Russian Far East, features. My proposal is to stay away from opinions if possible and to break both posts down. If we do it step by step, chances are we will get to a sound conclusion. Before I start, however, I want to do another post on Pikunov's article 'Population and Habitat of the Amur Tiger in the Russian Far East'. His proposals need to be discussed first, as they are of vital importance for tigers.
Peter says: One wonders why that advantage isn't used to displace male tigers. We also never heard anything about fights between adult males. What are we missing?
I have given this a lot of thought myself. Why would a big male grizzly weighing from 700 to 1000 pounds not displace a 400 pound male tiger from a carcass? My only conclusion is that should the tiger stand his ground to defend his kill, even though the bear might kill the tiger in the end, he would not ( IMO ) walk away from this battle unscathed. Tiger claws are nearly as long as grizzly claws. They are very sharp and a tiger is fast beyond belief. Then there are those canines which, in some individuals look almost like saber-teeth. Perhaps the prize is simply not worth the effort and the price. |
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