ON THE EDGE OF EXTINCTION - A - THE TIGER (Panthera tigris)

[peter]

(07-25-2018, 07:19 PM)wolverine Wrote:

(07-25-2018, 09:18 AM)peter Wrote: In the heavyweight division, large male bears may have the edge. 

Probably not only big male bears but any adult male brown bear. If the adult male tiger Matkasur weighting 200-220 kg from the famous video didn't succeed to overwhelm a smallish female Sloth bear weighting only 90-100 kg (that's the average mass of the female) and actually lost the battle how come a tiger can be stronger than adult male Ussuri brown bear with average weight of 270 kg... ?. That's unthinkable.
Its time for us - tiger lovers and lion lovers to open our eyes in the front of the truth and admit that the brown bear is way stronger than any cat. Sadly.
Nevertheless the obligatory predators as the big cats somehow are much more charismatic and excite human imagination much more than the omnivorus animals.

HOW TO GET TO A CONCLUSION ON MALE TIGERS AND BEARS - A

Over the years, I found quite a bit of good information on interactions between male tigers and male brown bears in the Russian Far East. In spite of that, I never got to a conclusion that would cover everything I read. 

One problem is the lack of information on the average size (a), individual variation (b) and the relation between size and age ©. Same for specific circumstances (d). Last but not least, those with experience contradict each other at times (e).  

In this first post, size and individual variation will be discussed.

a - Size and individual variation

a1 - Tiger

There is recent information on the size of Amur tigers (referring to the WCS-tables published just over a decade ago), but the samples are smallish and, to a degree, unreliable because 'problem animals' and 3-year old tigers were included. A bit strange, as every biologist knows that the differences between age groups in big cats often are pronounced, especially in males. 

Another problem is that most historical records are considered as unreliable. In spite of that, those involved in an evaluation of historical records published about a decade ago, concluded that male Amur tigers in the recent past (before 1970 or thereabout) were about 10-15% heavier than today. 

The information I have on captive male Amur tigers says individual variation is pronounced. In wild Amur tigers, on the other hand, individual variation is more limited than in all other tiger subspecies (...). The smallish samples could be a reason, but it can't be excluded that the recent population bottleneck and deteriorating conditions affected the size of wild Amur tigers after, say, 1970. 

As to contradictions on size. Slaght concluded that male Amur tigers averaged 389 pounds, whereas Miquelle said they averaged 430. Goodrich, when questioned by Guate, said Amur tigers have always been overrated, but Krechmar, on a Russian forum, said he had seen prints of large individuals.

So where does that leave us? For now, I use 270 pounds for adult females and 420 for adult males, but it could be that the real averages are different. I'm not sure about the average of captive females, but captive adult males are about 470-490 pounds. I have two reliable reports about (non-obese) females exceeding 440 pounds. 

When comparing measurements, weights and photographs of wild Amur tigers with those of captive Amur tigers (males), three things stand out:

- captive male Amur tigers nearly always are longer and taller than wild male Amur tigers;
- captive male Amur tigers show much more individual variation than wild male Amur tigers, and
- wild male Amur tigers (seem to) have, relatively, larger skulls.  

This regarding length and weight.

In the skull department, things are not much different. As a result of the lack of reliable information, V. Mazak's averages (published in the third edition of his book 'Der Tiger' in 1983) can still be found in many publications. 

In the scan below, you'll find measurements of (wild and captive) male Amur tiger skulls in the table on the far right. Notice that the sample size is limited. Same, by the way, for Panthera tigris virgata:
 

*This image is copyright of its original author

The longest skull V. Mazak saw belonged to a wild male Amur tiger shot in northeastern China. The greatest total length of that skull was 383 mm. Not so long ago, however, poster Betty posted a (scan of a) photograph of a skull of a 4-year old captive male Amur tiger with a greatest length of at least 420 mm. (...).

Here's the owner of the skull. At 4 years of age, he was 336,5 cm. in total length (head and body 240 cm. and tail 96,5 cm.). Tigress 'Hanya' also is a large animal:

*This image is copyright of its original author

*This image is copyright of its original author

Here's a photograph of his skull:

*This image is copyright of its original author

   

The tiger, from Howlett (UK), was just 4 years of age when he was shot. He still had some growing to do, that is. Based on the scale in the photograph, the greatest total length of the skull was about 431 mm. For zygomatic width and rostrum width, I got to 284 mm. and about 122 mm. respectively.

Warsaw has serious doubts about measurements based on skull photographs with scales. I understand, but one has to distinguish between photographs taken by amateurs and photographs taken by professionals. The photographs in the article about the Koln zoo tiger were taken by a professional. This means that the measurements I found using the scale in the photograph should be quite close to the real measurements.

In order to illustrate his point on photographs, scales and measurements, Warsaw added two photographs of skulls of (wild?) young adult male bears (Ursus arctos lasiotus). In the first photograph, using the scale, the greatest total skull length seems to be close to 450 mm. In reality, it was 415 mm. In the second photograph, using the scale in the photograph, the greatest total skull length seems to be close to 465 mm. In reality, it was 430 mm.: 

*This image is copyright of its original author

*This image is copyright of its original author

Using the scale in the photograph, the tiger skull has a greatest total length of 431 mm. (estimated). In this respect, it roughly compared to the two bear skulls above. The information on the bear skulls (referring to the difference between the optical illusion created by the photograph and the real length) suggest that about 35 mm. has to be deducted from an estimate based on the scale.

However. The photographs of the bear skulls, most probably, were not taken by a pro. The photograph of the tiger skull was. For this reason, the difference between illusion and reality will be more limited. A few days after the photograph was posted, Betty posted another photograph of a male Amur tiger skull. That photograph also has a scale:

*This image is copyright of its original author

I used the scale to estimate to greatest total length, the zygomatic width and the rostrum width. The results were not very different from the real measurements (the skull was measured). Poster Betty got to a similar conclusion. As the photograph of the skull of the male Amur tiger from the Koln zoo compares to the photograph of the old male Amur tiger from the Hamamatsu zoo (both protographs were taken by professionals), it is likely they also compare in the department of estimates based on the scale in the photograph. I'm not saying the greatest total length of the Koln zoo tiger really is 431 mm., but the difference between the estimate and the real length most probably is limited. Less than 35 mm., to be more specific.   
   
When comparing the skull of the young adult captive male Amur tiger from the Koln zoo with those of the two male brown bears (also young adults), a few things stand out:

- the 'snout' in the bear skulls is much longer;
- the tiger skull is wider as well as more robust at the arches;
- the rostrum of the tiger is wider and more robust;
- the sagittal crest of the tiger is larger and more robust, and
- the os frontalis in both bear skulls is wider and more robust.

The teeth of the captive male Amur tiger are not seen in the photograph above, but the article has another photograph showing the teeth: they are very large. In the teeth department, male brown bears do not compare to male Amur tigers. 

The anterior part of the captive male Amur tiger skull seems more robust and heavier. In both bear skulls, on the other hand, the posterior part of the skull seems more robust.   
    
a2 - Brown bear

In Amur brown bears (Ursus arctos lasiotus), the situation (datawise) isn't very different. Based on what was published, most assume that adult male bears, about as long as male Amur tigers (195-196 cm. in head and body measured 'over curves'), average about 580 pounds (Kucherenko). The average of females was impressive as well, but it later was decreased to 310-330 pounds by a poster with access to good information.

I only have one weight of a large captive male from the San Diego zoo. Male 'Blackie' was 396 kg. (874 pounds):

*This image is copyright of its original author

There is a bit more on individual variation. An average female could be 320 pounds, but females twice that weight have been shot in northeastern China more than once. It's quite likely that males are not much different in this respect. This means that the heaviest most probably exceed 1 000 pounds.

According to G. Baryshnikov, the greatest total skull length of an average male bear in that part of Russia is about 407-408 mm. (zygomatic width just over 240 mm.), but Wiki says it's just over 380 mm. (zygomatic width about 230 mm.). Here's the Baryshnikov table:

*This image is copyright of its original author

Individual variation in Amur brown bears is pronounced. In one direction? No, both ways.

Here's a table posted by Warsaw a long time ago. It has information on the size of adult male brown bears in northeastern Siberia. I know they're different from Ursus arctos lasiotus (a bit longer, but not as heavy), but it shows the significant amount of individual variation:

*This image is copyright of its original author

      

Here's a table that has weights of two male brown bears of the lasiotus type. Not even close to 580 pounds, but one of the two was a young adult male. Notice that both were weighed in late autumn, when brown bears peak:

*This image is copyright of its original author

a3 - Conclusions

Male Amur tigers average 420 pounds and 195 cm. in head and body length (measured 'over curves'). Male brown bears, with a similar head and body length, average 580 pounds. Solid info? I don't know. Krechmar said there isn't much to choose between most males of both species. The department of exceptional individuals, however, only has bears.   

Is an average male Amur tiger inferior to an average male brown bear of the lasiotus type? In head and body length, male tigers and male brown bears are about similar. Bears, however, are taller and more robust (heavier). Here's a drawing of the skeleton of a brown bear of the lasiotus type: 

*This image is copyright of its original author

Here's a drawing of the skeleton of an Amur tiger:

*This image is copyright of its original author

Here's a photograph of the skeleton of a (captive) 600-pound male Amur tiger (Taxidermy.Net Forum):

*This image is copyright of its original author

I've seen skeletons of both species next to each other. There's no question that skeletons of male brown bears are more robust than those of adult male Amur tigers. In the skull department, things are a bit different. Bears have a slightly longer and heavier skull, but skulls of male Amur tigers are not much shorter. They also have wider arches and larger canines. 

All in all, I'd say the differences between male tigers and male brown bears in the Russian Far East are quite limited. It also depends on the season. Bears are taller as well as significantly heavier in summer and autumn, but they lose up to 30% of their weight during hibernation. In early spring, they most probably are not heavier than an average male tiger.

The strange thing is that tigers hunt bears in summer and autumn, when brown bears, weightwise, are at their peak. Fights between male tigers and male brown bears, however, seem to occur most often in winter and early spring. Non-hibernating brown bears ('Shatuns') often are desperate animals, prepared to attack anything. In early spring, most male bears are not much heavier than an average-sized male tiger.    

a4 - Predation on male brown bears - speculative remarks

Are adult male brown bears in the Russian Far East out of the predatory reach of adult male Amur tigers? Weightwise, the answer is no. Some male brown bears are well below average. Also remember that male bears can lose up to 30% of their weight during hibernation. If they really average about 580 pounds in fall (assumption) and lose 30% in winter, the conclusion is that an average male bear is not heavier than an average male tiger in early spring.

Does that mean that experienced male tigers are able to take an average male brown bear in spring or summer? Biologists never found any proof, but weightwise it can't be excluded. 

In my opinion, one has to distinguish between a hunt and a fight. Tigers prefer bears they can quickly kill with a bite to the skull. In a mail to a poster of AVA, Linda Kerley said that adult brown bears up to the size of the largest female are hunted. Two large females killed by male tigers were estimated at 150-200 kg. (331-442 pounds).    

My guess is that male brown bears are not, or only very seldom, hunted. Adult male brown bears are known for their disposition. In this respect, they definitely compare to male Amur tigers. This, however, doesn't mean that Amur tigers will never try.

Adult male tigers have been killed by other male tigers in the Russian Far East. They can kill each other in a fight, but also ambush each other at times. Male tiger 'Uporny' was ambushed and killed by another male tiger in mid-winter (February). There were no signs of a fight. If a male tiger can kill another male tiger in an ambush, it's likely that a male bear similar in size to tiger 'Uporny' also can be ambushed.      

There is a difference between a hunt and a fight. According to those interviewed by Vaillant, male Amur tigers are prepared to fight a bear of similar size. If the tiger is victorious, however, the bear isn't always eaten. A hunt is about food. A fight is about something else. According to Russian biologists, a male brown bear victorious in a fight with a male Amur tiger always consumes his opponent. 

Wild Amur tigers seem to be quite uniform in size. In wild male brown bears, however, individual variation is pronounced. Some male bears are well below average, whereas others are very large. Based on what I saw and heard from trainers, I'd say that size often affects the outcome of interactions between adult males of different species. My guess is that many contradictions in the department of tigers and bears could be a result of the significant amount of individual variation in male brown bears. Variation is also seen in individuals (as a result of hibernation, nearly all brown bears in the Russian Far East are subject to outspoken fluctuations in weight). 

There could be other reasons.

in 2015, 'A comparison of food habits and prey preference of Amur tiger (Panthera tigris altaica, Temminck 1884) at three sites in the Russian Far East' was published. Researchers said that bears constituted 

" ... a relatively large portion of tiger diet, particularly during the snow-free period ... " (pp. 12). That conclusion ran counter to previous assertions that " ... the risk of injury was too high for tigers to regurlarly predate bears ... " (pp. 12).

Bearpredationwise, the differences between the three sites were quite striking. One wonders why that is. Here's a few ideas. 

- Maybe tigers in the southwestern part of Primorye are a bit larger than those in the north? Manchuria was known for the size of its tigers in the recent past. 

- Maybe brown bears in the southwestern part of Primorye are a bit smaller than those in the north?  

- Maybe there is a 'bear culture' in the southwestern part of Primorye. If tigers hunt bears that often, chances are tiger cubs learn about bears at an early age.

- Maybe the vegetation in Manchuria and the southwestern part of Primorye is more dense than in the north. If so, the cover would offer tigers more opportunities to hunt bears, especially in summer. 

- Maybe the southwestern part of Primorye is a hotspot for female brown bears with cubs in spring and summer?

- Maybe posters (and researchers) are a bit naive on tigers and bears in the Russian Far East. In his book published in 1993, V. Jankowski wrote the very large tiger shot in the summer of 1943 near the Sungari river had feasted on a bear of which only the head and part of a leg were found. Jankowski, as Warsaw said, didn't say anything about a fight and the size of the bear in his book. In his letter to V. Mazak, however, he wrote that the tiger had killed a very large old male brown bear a few days before he was shot. Why the difference between the letter and the book?

Maybe he regarded V. Mazak as a layman on bears and tigers in the Russian Far East. Maybe Jankowski, for this reason, decided to add a few details on the bear? I don't know, but his book suggests (the bear doesn't feature in his story on the Sungari river tiger) that Jankowski wasn't surprised at what he found. This should tell you something about his view on tigers and brown bears, as he was very experienced.

As to the size of the bear killed by the Sungari river tiger. According to Baikov, large tigers are able to ambush bears almost their own size. This remark was confirmed by recent observations of male tigers occasionally hunting large female brown bears (estimated at 331-442 pounds). Assuming that male Amur tigers were heavier in this day (460-480 pounds), bears of 400-450 pounds could have been included occasionally. It's likely that an experienced male tiger of exceptional size like the Sungari river tiger could have ambushed a 'large' brown bear. If he really was somewhere between 660 and 770 pounds (after consuming the brown bear), an average-sized male brown bear (580 pounds) would have been within reach. According to Bromlej, tigers are able to ambush a heavier bear.        

What I'm saying is nothing can be excluded. This regarding most male tigers and male bears.

Large male bears, however, are another story. According to Pikunov, large male brown bears definitely are not on the menu. All of those in the know (referring to Russian biologists) agreed. Vaillant, much later, confirmed: "... the only force a male (Amur tiger) will typically submit to is a stronger tiger or, occasionally, a large brown bear ... " ('The Tiger', 2010, pp. 140).   

The answer to the question as to what a 'large' male is, is difficult to answer. Assuming an average male is 580 pounds (Kucherenko), any bear over 600 pounds is large. A few months ago, photographs of a male bear of at least 800 pounds were published on the internet (see below). 

Although one wouldn't fancy the chances of a male tiger in a fight with a 'large' male brown bear, young adult male tigers in particular apparently are not afraid to fight them. I thought it was Rukovsky who found the remains of a male tiger killed by a 'very large' male brown bear. In spite of the difference in size, the fight had been prolonged. The skull indicated that the tiger had been a young adult (about about 4 years of age).

a5 - Brown bear density and vegetation in the Russian Far East

In order to be able to get to an opinion on some of the ideas discussed above, I decided to add a bit of information on brown bear density and vegetation. The info on the bear density is old, but the map on vegetation is quite recent.

- Brown bear distribution and density: 

*This image is copyright of its original author

Although the number of bears has diminished in the last decade (as a result of hunting), Primorye still has many thousands of bears. In the southwestern part, the density is lower than in the east and north. The 'bear culture' in the southwestern part, if there is one, is therefore not a result of a high bear density. This means that other factor have to be considered.   

- Vegetation:

*This image is copyright of its original author

The map says that a large part of the southwest is covered with broad-leaved Far East forest. In the northern and eastern part of Primorye, however, mountain taiga is common. It's very likely that broad-leaved forests offer a professional hunter more cover. My guess is that broad-leaved forests, foodwise, would be more interesting for bears as well.
           
a6 - Photographs

Brown bear (Ursus arctos lasiotus)

An Amur brown bear is also known as a 'horse bear' because of its long limbs. They're taller at the shoulder than a wild male Amur tiger. Here's an average-sized wild male. Watch the length of the skull and the legs:

*This image is copyright of its original author

  

Here's a large and very heavy wild male bear. Based on the size of the tigress in the next photograph, he could have been about 800 pounds:

*This image is copyright of its original author

Here's the tigress he extorted:

*This image is copyright of its original author

Warsaw said the male brown bear was large, but old. He added this picture of a large male bear in his prime:

*This image is copyright of its original author

Amur tiger (Panthera tigris altaica)

Small male killed in a fight with another tiger. Most posters thought it wasn't an adult male:

*This image is copyright of its original author

Wild male tiger of about average size. This tiger died as a result of a disease. Just before he perished, he fought and killed a large wild boar:

*This image is copyright of its original author

Large-skulled wild male tiger: 

*This image is copyright of its original author

Very large male tiger. In his letter to V. Mazak, V. Jankowski said this tiger, shot near the Sungari river in 1943 in northeastern China, was at least 300 kg. In his book, he said it was 350 kg. (771 pounds). That was after he had consumed a brown bear, of which only the skull and part of a leg remained. Again notice the size of the skull:

*This image is copyright of its original author

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