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RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - peter - 06-11-2015
(06-11-2015, 06:32 AM)'tigerluver' Wrote: @peter, I've a very important question regarding skull measurements in literature. Christiansen, using a digital method of measurement, began playing with positioning of the skull for measurement. The result seems to be his skull measurement method does not match with the conventional one in older literature. As the picture shows:
*This image is copyright of its original author
Method A is the method you have used as well as other literature from the last century I've read. Method B is Christiansen's new method. Method B looks to measure a short length. Now, have you read/met anyone who has used the method B skull position for length measurements?
To all, examine the photos, have I made a mistake in measuring the length lines in the lower picture?
01 - The photograph of the skull was made after it was measured. The skull was photographed to compare it to others.
02 - Every skull was photographed from the same angle, but I had a different photographer every time I visited a museum. At times, it was a pro and at times it was the conservator himself.
03 - The lines in the photograph you used were drawn to show those interested in what way CBL and GTL were measured.
04 - When I measured CBL and GTL, I didn't use the complete skull. The reason is the measurement is increased when you measure CBL and GTL in this way, even when the skull is resting on a flat surface. For this reason, I decided to only use the upper skull to measure CBL and GTL.
05 - The upper skull of a big cat has large canines. If the upper skull is placed on a flat surface, the result will be an angle. An angle you don't want, because it will have an effect. In order to position the teeth of the scale at the correct places and prevent angles, the skull was placed on my lap. If the CBL was measured, the skull was turned upside down. When the GTL was measured, it was the other way round. Doing it this way enabled me to work in a proper way. With the skull on my lap, I positioned the teeth of the scale at the correct places, lifted the skull to the table with the (digital) scale attached to it and measured the distance between the two teeth of the scale in full view of the one assisting me. He or she, at my request, then told me if I had placed the teeth at the correct places. The procedure was repeated three times. The measurement used was the average of three attempts. The differences between every attempt were 1-2 mm. at most.
06 - Working in the way described above, GTL, CBL, zygomatic width, maxillary width, length of the upper canines in a straight line, width of the upper canines at the insertion of the jaw (from front to back), skull height at the orbit (with the mandibula attached to the upper skull and a horizontal scale at the top of the orbit in order to be able to measure the distance from the flat surface to the highest point of the skull) and the Pm4 were measured. Then the skull was weighed. I also added a remark on the condition of the skull (defatted or not).
07 - After the measurements were taken, the skull was described and compared to others. Then the information on the label was noted. Quite often, I asked the conservator to assist me. The reason was most labels were old, unclear or even incorrect. If a measurement was out of the ordinary, I asked others in the museum to measure the skull. In this way, assisted by someone interested and the photographer, every skull took 30-45 minutes, at times up to 60 minutes. If a museum, for example, had a collection of 70 big cat skulls, I usually needed at least a week. For the Stuttgart collection I needed the best part of two weeks.
08 - At home, all measurements were inserted into the tables I had prepared. The descriptions and the tables combined resulted in a document of 20-40 pages. I kept one for myself. The other was sent to the conservator, usually with a big thank you.
09 - Before I started measuring skulls, I read everything available. Although Pocock's description was the best, it was Dr. P. van Bree who showed me how it was done. He also collected articles for me and told me about things I had to know. A great pity he had to retire. Each of the conservators had special skills, but Dr. Doris Morike (Stuttgart) was one of the most informed.
10 - Every now and then, I visit a biologist interested in skulls to talk about the things I noticed. One of the best informed was a biologist in Belgium. He and his wife (also a biologist) got an offer they couldn't refuse just after they graduated. A bakery, that is. Bread, cake and related. But he continued collecting skulls and when I came over to measure them, he was so interested we had a debate every day. Very often, he worked on something very different. Something I didn't see. This also often happened in the museums I visited. At first, they thought I was quite mad, but nearly all conservators ended up sitting next to me. They were as interested as I was.
11 - The above suggests measuring a skull wasn't a piece of cake. If I would say it compared to fysical labour, I would be close. I know many of today's biologists measure skulls in another way. They don't go to museums anymore, but ask their peers for photographs and get them. Excellent photographs they are, way better than the ones I have. But I always wondered how they do it. I mean, I just can't imagine measuring a skull in this way. I think you need to have a skull in your hands in order to get to an idea. When I say I like skulls of wild Javan tigers best, I have a reason for it. It's difficult to explain, but there is a reason. But today is the day of limited dimensions and I guess measuring a skull by using a few photographs would fit in quite nicely.
12 - As for the question regarding Christiansen and the new way to measure skulls. You can learn how to play the guitar by reading a book, but you also could start playing right away. Everything you discover is yours. Doing it in this way will help you understand things that can't be explained. The best, I think, are the ones who did it that way. Not because they have more skills, but because what they do has more weight (meaning). And this you hear right away. And then there is playing in a team and knowing what to do or don't. Everything that matters has no shape. You can't see it and you can't touch it, but it is there and it is crucial.
But I don't doubt that Christiansen will prove me wrong. I read a number of his articles and thought they were both very interesting and well over par. He can play the guitar, but it seems to be one I don't know.
This post took me some time, but it was worth it. I've never explained how I measure skulls. Explaining it was interesting in that I became aware of things I wasn't aware of. When things are unclear, say so. I'll do my best to get to a clear answer.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - tigerluver - 06-11-2015
Much, much thanks for the in depth description. I will have to read it another dozen times at least in the coming days. Though, in order to better help me visualize, I have a few questions. By upper skull, you are referring to the cranium, lacking the mandible, correct? By scale, are you referring to sliding scale that has similar mechanics to the caliper?
Moreover, when measuring GTL, you stated you have the skull upright, with the skull on the lap. If I am understanding this correctly, the scale was positioned between the two points of interest. You then brought the skull up to the table for the measurement. Now, relative to the table, how does the skull positioning look exactly? I'm having trouble seeing it, as I have the Christiansen method currently engraved in my head. When I think compensate for the angle, I think "method b's" positioning.
I'll have more questions about the method specifically, but I first need to grasp these points.
Now beyond your method specifically, how compatible do you think skull measurements from different literature are? I feel some authors have taken the idea of "greatest length" to be that when the canines are angling the skull relative to the plane below, as this position does produce in essence the "greatest" length if taken literally. I'm very certain vK has done this. Then, there's Christiansen. If he truly did measure the skull as he has shown, CN5698 would have an angled, vK style CBL of around 375 mm, which seems too large. My direct interest in this issue at the moment is how it affects my equations and all current weight estimates. Depending on the "measurer," a skull length may be inflated.
I understand the benefits/convenience of digital measuring. It might also provide a way for a level playing field between literature. At the same time, I agree that you can't beat an in person measurement if the option is available.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - brotherbear - 06-11-2015
Peter says: ~I saw it. It also was observed in Russia, but most brown bears who skipped hibernation, as far as I know, didn't survive. Could be a result of the long winter and could be a result of a lack of servants, I mean wolves. I know some of these 'satellite bears' follow and extort tigresses with cubs, but this strategy apparently doesn't pay in the long run. A brown bear who skips hibernation in eastern Russia very often starves to death:
I agree; bears are not in a class with wolves or big cats when it comes to hunting. A lot of people believe that bears sleep through the winter months because they can not handle cold weather. But, there is little in the way of vegetation or even insect food for bears in winter time and they are poor predators. That particular grizzly did alright for himself but that was imo an exception to the rule.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - peter - 06-11-2015
(06-11-2015, 09:28 AM)'tigerluver' Wrote: Much, much thanks for the in depth description. I will have to read it another dozen times at least in the coming days. Though, in order to better help me visualize, I have a few questions. By upper skull, you are referring to the cranium, lacking the mandible, correct? By scale, are you referring to sliding scale that has similar mechanics to the caliper?
Moreover, when measuring GTL, you stated you have the skull upright, with the skull on the lap. If I am understanding this correctly, the scale was positioned between the two points of interest. You then brought the skull up to the table for the measurement. Now, relative to the table, how does the skull positioning look exactly? I'm having trouble seeing it, as I have the Christiansen method currently engraved in my head. When I think compensate for the angle, I think "method b's" positioning.
I'll have more questions about the method specifically, but I first need to grasp these points.
Now beyond your method specifically, how compatible do you think skull measurements from different literature are? I feel some authors have taken the idea of "greatest length" to be that when the canines are angling the skull relative to the plane below, as this position does produce in essence the "greatest" length if taken literally. I'm very certain vK has done this. Then, there's Christiansen. If he truly did measure the skull as he has shown, CN5698 would have an angled, vK style CBL of around 375 mm, which seems too large. My direct interest in this issue at the moment is how it affects my equations and all current weight estimates. Depending on the "measurer," a skull length may be inflated.
I understand the benefits/convenience of digital measuring. It might also provide a way for a level playing field between literature. At the same time, I agree that you can't beat an in person measurement if the option is available.
1 - " ... By upper skull, you are referring to the cranium, lacking the mandibula ... "? Yes.
2 - " ... Sliding scale with similar mechanics to the caliper ... "? Yes. The scale can measure skulls of up to 500,00 mm. in GTL.
3 - " ... You then brought the skull up to the table for measurement. How does the skull positioning look exactly ... ? Not important. What is important, is that GTL is measured with the scale (and not the skull per se) positioned on a virtual horizontal line. To do that, I used the table and the one assisting. When the measurement was taken, the skull wasn't on the table, but just above it, I mean. I held it in my hands and positioned the skull in such a way that the scale, compared to the table, was completely horizontal. This means I used the table (and the one assisting) to position it in a virtual horizontal line. Important? Yes. If it wasn't positioned in that way (but the skull, for instance), the measurement would be increased. Sure? Yes. It was tested.
4 - " ... How compatible are skull measurements from different literature ... "? I don't know, but I do know there are many ways to measure a skull. Everyone probably thinks his method is the best. Same for me. Also remember modern (digital) scales are more accurate than the old ones.
Some of the skulls I measured were also measured by others. When comparing the results, I noted there wasn't much difference regarding Pm4 and zygomatic width. The Pm4 is small. You just measure the distance between both ends in a straight line and that's it. Zygomatic width also is easy to measure. I can't say anything about upper canine length, as most didn't measure the upper canines in big cat skulls.
The results of measurements of maxillary width, greatest total length and, in particular, condylobasal length often were somewhat different. Too much to understand, I concluded in some cases. The most likely reason is the method used. In maxillary width, it's understandable, as it heavily depends on the place you measure the width.
Condylobasal length, however, should be easy to measure. You insert the first tooth of the scale at the tip of the palate (directly behind the insertion of the incisors) and the second directly behind outer back edge of the condylae. Than you measure the distance between both points with the scale positioned on a (virtual) horizontal line. Apparently not that easy. One reason is not all insert the first tooth of the scale in the same position. In nearly every skull, you can see many insertions. They all use a different place, and the obvious result is different measurements.
GTL should be easy as well. You insert the first tooth of the scale just before the insertion of the incisors in the maxillary bone and the second directly after the outer back edge of the occipital ridge. The problem is removing the angle(s). If the measurement isn't taken on a virtual horizontal line, the measurement will be increased. This takes a bit of work, as I explained above.
As for the results. I noticed my measurements (and GTL and CBL in particular) were a bit shorter in most cases. Reasons explained above. In order to learn a bit more, I asked others to measure skulls. Competent people who should know about skulls and measurements. I watched them and saw they didn't need a lot of time, whereas I did. The reason is I measured hundreds of skulls and, for this reason, know inaccuracy is close when you don't pay attention. Measuring skulls really needs concentration and time. I also concluded (hidden) preference can be a factor. You can measure a distance in a straight line with a reliable scale and, apart from including angles, still deduct or add a few mm. if you want to.
5 - Although I read a lot about measuring skulls before I started (a), Dr. P. van Bree taught me how it should be done (b). Later, when I had gained some experience, I noted measuring a skull takes more time than I anticipated ©. Modern, digital, scales are more reliable than the old ones (d). And then there's angles and (hidden) preference (e). All in all, measuring skulls is a bit of an undertaking.
If you want to know about the reliability of skull measurements, accept you won't find the answer. Not without indulging in generalisations and (some degree of) preference. You will insult some and my advice is to refrain from it. As for my measurements. I did my best to get as informed, experienced and accurate as possible. I also took my time and I learned about (hidden) preference. We're all humans, degree or no degree.
As to preference. Let's take tigers and bears. Russia. Many biologists think tigers preying on brown bears take a risk, especially when adults are involved. Miquelle (2010) thought it would be a dangerous undertaking and he wasn't the only one. But there's mounting evidence they, to an extent, could be wrong.
Today, I read an interesting article about Amur tigers and food. Kerley was involved and so was Miquelle. The conclusion is tigers prey more often on bears than many think, especially in summer. The percentages they found were quite impressive. Although details were still lacking (age? - weight? - health? - circumstances?), the word 'adults' (referring to bears) was included in the document. This should tell you something.
Biologists are better educated and trained than most posters. They also are much better informed. That, however, doesn't always mean they are very different from posters with firm opinions. The difference between them is posters will never change their opinion, whereas biologists do. When they're true biologists interested in reality. And they very often are. If what I saw in captivity and heard from experienced trainers would hold for wild animals, things could be different than many think. But that's another topic.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - peter - 06-12-2015
LARGE CARNIVORES AND THE CONSERVATION OF BIODIVERSITY (edited by Ray J.C., Redford R.H., Steneck R.I. and Berger J. - Island Press, 2005).
Chapter 10 - Amur tigers and wolves (Miquelle et al.)
Our new member Bremhji posted a link to the book mentioned above. I read chapter 10, which is about Amur tigers and wolves in the Russian Far East. Well written and very interesting, I think. Recommended. While reading, I made some notes. This post has information about the things I liked best.
In order to prevent problems, I decided to use quotes whenever possible. Remember some parts were left out in order to improve readability. The parts left out were either references or sentences that served as illustrations of statements. In between the quotes, I will add a few remarks. The titles of the paragraphes (and Chapter 10) are mine.
a - Why wolves numbers have fallen in Sichote-Alin: tigers
As was stated before, rumours about wolves and Amur tigers compare to those about bears and tigers. What is known, is wolves and tigers do not use the same areas. Not today. This paragraph has a few quotes as to why that is:
" ... Based on fieldwork ... through the early 1970s, Gromov and Matyushkin (1974) argued against the perception, common in Russia, that wolves are driven to low densities or extinction in the presence of tigers ... " (pp. 188).
" ... Despite the clear inverse correlation between wolf and tiger numbers, the mechanism driving population declines of wolves is unclear. Gromov and Matyushkin (1974) reported both usurpation of wolf kills by tigers and scavenging of tiger kills by wolves. The former has probably not been a primary factor influencing wolf distribution. Gromov and Matyushkin (1974) believed that tigers did not prey directly on wolves, and along with others (Yudin 1992) proposed that wolves actively avoid areas used by tigers, resulting in spatial separation of the two species as tiger abundance increases, with wolves remaining only in peripheral areas. However, simple displacement and avoidance seem unlikely to explain the dramatic decrease in wolf numbers across such large areas ... " (pp. 188-189).
" ... Although there are only four records of a tiger killing a wolf (Miquelle et al. 1996; Mokovkin 1999), Amur tigers are notorious for killing dogs. Although rarely observed, direct killing of one predator by another is suspected to play an important role in limiting many predator species (Palomares and Caro 1999; Woodroffe and Ginsberg, this volume). Thus, despite the lack of clear evidence, we propose that direct killing of wolves by tigers has likely been an important element in reducing wolves to a functionally insignificant role in the Sikhote-Alin ecosystem ... " (pp. 188-189).
What they are saying is Amur tigers and wolves use different areas in the Russian Far East today. Nobody knows why that is. Tigers could have been involved, but there is no strong evidence to suggest they habitually prey on wolves. The number of wolves killed in half a century is very limited. If we add the one killed by tigress Ilona recently, the total number is five only. In spite of that, biologists think tigers are partly responsable for the decrease of wolf numbers. Hmmm.
b - Why wolf numbers have fallen in Sichote-Alin: hunters
" ... In Russia, ..., large carnivores are primarily viewed as competitors to human hunters. The general conclusion in Russia is that wolves can significantly depress ungulate populations and should be controlled to maintain high ungulate yields for hunters ... " (pp. 203).
" ... Our conclusions that tiger predation is unlikely to limit ungulate populations to the same extent as wolf predation concur with opinions of local biologists (Kucherenko 1974; Dunichenko 1987) ... " (pp. 203).
" ... Nonetheless, the relationship between tigers and Russian hunters is less than amicable, and 'intraguild' killing of competitors extends to the hunter-tiger relationship. Abundant evidence suggests competition killing is one of the primary motivations for poaching in Russia (Miquelle et al. in press). Due to this inimical relationship, and because new regulations provide nongovernmental hunting groups with wide-ranging responsabilities to manage game species, hunters will be key stakeholders in determining the future of tigers in the Russian Far East (Miquelle et al. in press). Finding common ground with hunters must therefore be a primary task for those wishing to conserve the Amur tiger. Paraphrasing one argument for tiger conservation, local conservationists and biologists have proposed to local hunters that 'while tigers may not be desirable, they prevent wolves from becoming abundant ... and we all know that wolves are worse worse than tigers in depressing prey numbers, so it is to your advantage to tolerate the tiger' ... " (pp. 204).
These quotes strongly suggest that hunters largely determine the future of animals, and large carnivores in particular. Although it isn't stated with so many words, there's no question that wolves are a prime and legitimate target of hunters. The reason is wolves are more destructive than tigers:
" ... Nevertheless, our simulations suggest that wolves can limit prey to a much greater degree than can tigers ... " (pp. 203).
c - Why wolf numbers have fallen in Sichote-Alin: conditions not favouring social hunters
" ... Estimates of energy requirements ... suggest that wolves eat more than would be expected for their body mass, whereas tigers eat less than would be expected ... " (pp. 202).
In order to explain the high requirements of wolves, hunting mode and sociality are discussed:
" ... As ambush predators, tigers hunt by stalking followed by very short rushes (Yudakov and Nikolaev 1992), with high success rates (Hornocker 1970). Chases by tigers rarely extend beyond 150 m (Miquelle et al., unpublished data). Yudakov and Nikolaev (1992) reported 54% and 38% success of Amur tigers hunting wild boar and red deer, respectively. Because tigers are solitary, intervals between kills are high (six to nine days). Collectively, high success rates, short chase distances, and long intervals between kills result in low energy expenditures for tigers.
By contrast, wolves have low success rates, averaging 14% over 14 studies (Mech and Peterson 2003). As cursorial predators, they may chase prey for kilometers. Although living in groups provides wolves the capacity to kill large prey and obtain greater biomass per kill (Gittleman 1989), group living also has costs. In particular, sharing kills results in less energy acquired per individual per kill. Consequently, kill rates must be higher for wolves, leading to greater travel distances as packs search for prey. An additional cost of group living is the time and energy expended on social interactions, a cost that solitary species like tigers largely avoid. In summary, higher kill rates (a consequence of sociality), as well as greater energy expended in cursorial hunting (greater chase distances) and social interactions, all result in greater energy demands for wolves. These factors likely explain much of the difference in food consumption between wolves and tigers ... " (pp. 202).
This factor, I think, is more important than all others. In the Russian Far East, wolves, as a result of their way of living, struggle to make a living. Sociality also doesn't help.
d - Why wolf numbers have fallen in Sichote-Alin - conclusions
1 - Conditions in the Russian Far East do not favour social carnivores like wolves. The reason is their way of life results in a more or less permanent energy deficit. In the long run, this can only result in adaptions and they didn't disappoint us. Wolves in the Russian Far East usually live alone or in small groups. The days of large packs are past and gone, that is.
2 - Although direct predation by tigers doesn't happen often (only five incidents in half a century), wolves most probably avoid tigers because they are able to kill them. As a result, wolves and tigers use different areas.
3 - Another factor not to be underestimated is hunters. Large carnivores are considered as competitors of hunters in Russia. Tigers have a small advantage because they limit wolf numbers, but wolves have no credit at all. As hunters eliminated tigers, there's no question they will eliminate the one not supported by anyone at every given opportunity.
All clear, I think. There are, however, two questions:
a - Why is it wolves were seen in large packs in a region known for tigers (the eastern part of the Sichote-Alin Mountain Range) about a century ago by Velter and his companions? I mean, they caught 26 in a wolf trap in 6 weeks only.
b - Why is it timber wolves in the Russian Far East, known because of their large size, seem unwilling or unable to take on tigers if we also know they do not hesitate to harass and attack brown bears, who can grow to a larger size than tigers?
e - A few pictures
1 - Winter Ecology of the Amur tiger (Yudakov and Nikolaev): Great study. Buy it when you can:
*This image is copyright of its original author
2 - Ussuri forest:
*This image is copyright of its original author
3 - The actors featuring in this post side by side:
*This image is copyright of its original author
4 - Tiger and wolves in the RFE (Bisley). This probably never happened, but it's a nice painting anyhow:
*This image is copyright of its original author
5 - Moonlight wolf. Can't get enough of this one:
*This image is copyright of its original author
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - Brehm - 06-12-2015
Great post Peter! Logical conclusions and a nice summary.
About your questions:
~a - Why is it wolves were seen in large packs in a region known for tigers (the eastern part of the Sichote-Alin Mountain Range) about a century ago by Velter and his companions? I mean, they caught 26 in a wolf trap in 6 weeks only.
One possible reason could be a more balanced ecosystem, with less human interference in those days. From what i've understood after your description, it looks like that the russian far east is a fragile environment for wolves, due to the reasons you listed. They face harsher conditions than their relatives from north america, which mostly live in a similiar environment, BUT, and there is a big but, they don't have to face tigers AND bears at the same time. There is also less prey variety in the amur region, so there is direct competition over the same prey especially with tigers. If hunter's also come into play and wolves are their prefered competitors to eliminate, they are the one's who will suffer the most from human and natural impact.
~b - Why is it timber wolves in the Russian Far East, known because of their large size, seem unwilling or unable to take on tigers if we also know they do not hesitate to harass and attack brown bears, who can grow to a larger size than tigers?
After watching several documentaries, where wolf - bear interaction is showed, i think it could be wolves fighting style against larger predators. Against bears, they usually seem to harass them one by one from different angles. Even if they could overpower the bear (if numerous enough) if they would decide to charge from all angles, they don't want to take risks by losing members. In the documentary "viking wilderness", this tactic worked out, the bears were to slow and unable to catch a single wolf in the long run and cancelled the fight. The bear's weren't in real danger after all, but they quit and l
Against a tiger, this tactic won't pay possibly. Usually faster and more agile than a bear, a tiger could take out 1 or 2 wolves quickly, and if that should be the Alpha male or female...everyone can imagine.
My thought's, does it sounds plausible?
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - brotherbear - 06-12-2015
Remember though, that in the 'Viking Wilderness' the European brown bears are rarely as large or as aggressive as an American grizzly or a Russian black grizzly. I have watched more than one documentary where a big grizzly took a carcass from a large pack of grey wolves relatively unchallenged. Perhaps if the wolves were suicidal, they might kill the bear, but likely with considerable loss. I would think that the same would hold true with a tiger.
I will add that, in Yellowstone, it has been proven that bears actually benefit by the presence of wolves.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - Pckts - 06-12-2015
(06-12-2015, 05:01 PM)'brotherbear' Wrote: Remember though, that in the 'Viking Wilderness' the European brown bears are rarely as large or as aggressive as an American grizzly or a Russian black grizzly. I have watched more than one documentary where a big grizzly took a carcass from a large pack of grey wolves relatively unchallenged. Perhaps if the wolves were suicidal, they might kill the bear, but likely with considerable loss. I would think that the same would hold true with a tiger.
I will add that, in Yellowstone, it has been proven that bears actually benefit by the presence of wolves.
They also suffer as well, predation on cubs, competition between them, other than a large male grizzly, all other bears are in direct competition with wolf packs.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - GuateGojira - 06-13-2015
peter\ dateline='\'1433884286' Wrote: Male Amur tigers average 195 cm. in head and body length in a straight line. Male Ussuri brown bears average 196 cm. 'over contours'. Same as Yellowstone male brown bears. As the Yellowstone male brown bears were 32 cm. shorter in a straight line (164 cm.), one has to assume the Ussuri's would be about similar if they would have been measured in a straight line. Male Amur tigers, therefore, are 31 cm. longer in head and body length in a straight line. Seen from this perspective, one could say Guate was quite generous to the Ussuri male brown bear in the comparison.Maybe I was "generous" like you say, but I tried to stay true to the measurements, after all, there is no evidence about how those bears were measured, as they were not taken by American scientists, but by Kucherenko in Russia. Besides, I can't see that animals with skulls of no less than 380 cm, could measure only 164 cm in head-body, which will be similar to sloths bears in India (I try it, and it looks too small). Maybe the Grizzlies of Yellowstone are just smaller than those of the Russian Far East (this seems correct), or maybe is just the sample size (10 against 55).
Guate was generous in other respects as well. Kucherenko wrote Ussuri male brown bears average 264 kg. (583 pounds) and Goodrich said they average about 270 kg. (596 pounds), but 2 adult males recently weighed by biologists were 180 and 235 kg. (207,5 kg. or 458 pounds) on average. Quite a difference, that is. Same for females. Kucherenko wrote they averaged 189 kg. (418 pounds), but recent information points towards 140-150 kg. (320 pounds).
As I don't know what to make of it, I propose to take 543 pounds (246 kg. roughly) for now and assume it's a year-round average. In females, the average would be 369 pounds, say 360-380 pounds for now.
The average for male Amur tigers, on the other hand, could be a bit higher in most departments. The WCS-table used by Guate included a number of young adults (a). Some of the tigers, weightwise, were well under par (b). Three is the Aldrich footsnare used to capture Amur tigers failed on at least two occasions ©. This means large males might be able to break free, which would affect the average to a degree. Not saying those who escaped the footsnare were well over 440 pounds, but they were large males and they were not weighed.
All in all, one could perhaps say healthy male Amur tigers, at 190-200 cm. in head and body length measured in a straight line, average 420-440 pounds, whereas male Ussuri bears, at 160-170 cm. in head and body length measured in a straight line, could average 540-550 pounds. Male Ussuri brown bears, therefore, are both absolutely and relatively more robust. They also produce more exceptional specimens. When both animals would be seen close to each other, the picture that emerges could be close to the one Guate produced.
Here's the table on Yellowstone brown bears I referred to above. It is about the average difference between 'length' and 'contour length' in 55 adult males (older than 5 years of age) at the bottom of the table. Also take notice of the average chest girth, height and neck girth:
*This image is copyright of its original author
Here's a photograph of a male brown bear of 275 kg. (607 pounds) who reached 223 cm. on his hind legs. It was posted a long time ago by Warsaw. The bear, if I remember correctly, was exhibited somewhere in Canada, but I'm not sure:
*This image is copyright of its original author
This is the famous picture of the diorama again. The more I see it, the better I like it. Based on what we know, it could be quite accurate. Both are about similar in length (tiger a bit longer), but the bear is more robust and heavier:
*This image is copyright of its original author
The scenario in the photograph (male against male) is an unlikely one. Bart Schleyer, based on what he saw in the snow, said that tigers who hunt bears (most often older males) usually have about a 100 pounds on them. This advantage allows for a quick kill (a bite to the base of the neck). In at least two cases, the ambush developed into a 20-minute fight. The most likely reason was size in that both bears involved, adult females, were (visually) estimated at 150-200 kg. The male tigers who fought them probably were about similar in weight. In both cases the brown bear was killed, but the tigers were injured.
Some Ussuri male bears follow tigers in order to rob or even hunt them. These 'satellite bears' target immatures and females with cubs. In Heptner and Sludskij (German translation of 1980), a number of incidents between large male brown bears and tigresses or adolescent tigers were described. The conclusion is male brown bears, like male tigers, prefer to attack smaller animals.
There's no question males clash at times, especially in years with crop failure and mass migration of prey animals (deer and wild boars), but all-out fights seem to be singular events.
On the weight issue, I don't see why the average of Kucherenko could be wrong. For the contrary, it shows that most of the males weight around 260-270 kg with maybe just one exceptional male of 320 kg. Check that the sample is of 10 males, so 9 were probably between the first range (I am speculating, but based in real possibilities). This figure was confirmed by modern studies like those of the Siberian Tiger Project, sadly they are not willing (yet) to share more data on they bears. Still, the data suggest that adult male bears in the area do weight about 260-270 kg, with just one exceptional case of 320 kg.
I am interesting in the sources of the three male bears that you quote (165, 180 and 235 kg) in order to include them in the comparative image.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - GuateGojira - 06-13-2015
Well, here it is, my comparison of the Amur tiger and the Grizzly bear (population of Yellowstone NP):
*This image is copyright of its original author
We can see how small is an average male bear compared with an average male Amur tiger. If peter is correct, this should be also the size of the Ussuri bears, on average.
This is the link for the document where I get all the data of the Grizzly bears: http://www.bearbiology.com/fileadmin/tpl/Downloads/URSUS/Vol_7/Blanchard_Vol_7.pdf
Take in count that the variation in weight is because in the early dates, the garbage were easily available for the bears, so they eat more dump. In latter dates, there was more control and the sample used here is that in table 2.
Greetings.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - brotherbear - 06-13-2015
193.3 kg or ( in my language ) 419 pounds. This is very likely a good rough estimate of a male Yellowstone grizzly ranging from about 5 years old and up; I presume summer weight. I believe that if we average out only those fully mature grizzlies from the age of 9 and up we will be looking at roughly 500 pounds. At least that is what I found from one chart that I had once discovered. In seeking an average weight for brown bears, there are many variables to consider.
Of course, a tiger is just as likely to happen upon a 5 year old as a 10 year old. The age of each predator would make a significant difference on how such a confrontation might play out. By the way; I really like these comparison pictures.
*Edit - ah, I see that Peter agrees with me; post #665... ~~As I don't know what to make of it, I decided to take the average of Kucherenko (n=10) and the 3 recently weighed brown bears (n=3). This results in 505 pounds for an average male. I propose to take 490-520 and assume it's a year-round average. In females, the average would be 369 pounds, say 360-380 pounds for now.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - GuateGojira - 06-14-2015
I made my own investigation and I have found the source of the three new weights from male bears in the Russian Far East
ulsar Satellite Radio Beacon Application Experience in the Telemetry of Brown Bear (Ursus Arctos L.)- Ivan V. Seryodkin[sup]a[/sup][sup], [/sup][sup], [/sup],
- Vitaliy A. Zaitsev[sup]b[/sup],
- Yuriy K. Petrunenko[sup]a[/sup]
The article is free, so you can download it right now.
I am going to change my image in order to show this three figures in the table. I am going to take out the "averages" from Goodrich, as there is no more data and for lack of space in the image.
Wait for the new image, but take in count that the size of the bear will be the same, I can't change it despite our suspicious about the method of measuring. Maybe I can scale it a little smaller, but that is all I can do.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - GuateGojira - 06-14-2015
Well, here is the new comparative image about the size of the Amur tiger and the Ussuri brown bear:
*This image is copyright of its original author
As you can see, I scaled the bear a little smaller and I put a foot note about the possible way of the measurements.
Other thing, I found that the bears were not measured in 2003, but they came from the early books of Kucherenko of 1972 and 1973, so those bears were probably taken between those dates.
Now it includes the new 3 males from the region, which are adult ones.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - brotherbear - 06-14-2015
It is rather easy when looking at these great comparison pictures to understand why the mature males of each species generally avoid each other. Neither could possibly walk away from a fight without some serious injuries IMO.
RE: ON THE EDGE OF EXTINCTION - A - TIGERS (Panthera tigris) - Kingtheropod - 06-15-2015
T24 is well and good
Just before we celebrated the news of tiger numbers swelling, Ranthambore reserve had a bit of a scare two weeks ago. One of its tigers, code-numbered T24, fell seriously ill. It started with constipation, but quickly turned into obstipation, the animal was unable to pass any stool at all.
The commonest cause for such a situation is hairball formation combined with some large pieces of bones in the animal’s intestine. Scat turns into a hard and stony substance and leads to impassable blockage. Forest guards found that the tiger would try very hard to defecate, squatting all the time, but to no avail. The vets tried to give him oral laxatives mixed in chicken, but T24 would sniff at it, but never consume it.
When the tiger’s condition did not improve in more than a week, worried foresters consulted all possible experts. While some vets suggested surgery, tiger expert Valmik Thapar advised against intervening in nature’s course. Post-operative care of a wild animal is impossible without holding it in prolonged captivity. T24 had already been kept in captivity for four days during treatment for a leg injury. After this, he killed three people in different incidents, when they ventured too close to him. Experts connected these incidents with some past captivity stress, which is why this time around, they were scared that after such a big surgery, they may not be able to release T24 into the wild again.
Park managers, therefore, decided to give him some external help through an enema of laxative. They shot some sedative drug darts at him, but the 240 kg massive male tiger managed to climb onto a small hillock. He hid behind a big boulder. Tension and apprehensions were heavy in everyone’s mind, because it wasn’t clear if the tiger had been tranquilised or not. A single slap of a tiger can permanently disable or even kill, so the guards approached him cautiously and found, to their relief, it asleep. They then brought the animal to the hill-base. After the veterinarians completed the enema-job, the tiger disappeared in the bushes. Two days later, on the 13th day that is, T24 finally managed to answer nature’s call, and everyone heaved a sigh of relief.
*This image is copyright of its original author
This report was written by Dharmendra Khandal, he is a conservation biologist at Tiger Watch, Ranthambore.
https://www.google.ca/#q=tiger+240+kg+T-24&tbm=nws
*This image is copyright of its original author
credits to Apollo