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

[peter]

URSUS ARCTOS LASIOTUS AND PANTHERA TIGRIS ALTAICA

Nice comparison, Guate. I don't doubt some of those interested in bears will have some objections as to the size of Ursus arctos lasiotus, but the problem is a lack of reliable information. All we have is Kucherenko and the recent article of Seryodkin and the information regarding weight is contradicting. Let's see what we can find about Ursus arctos lasiotus and Panthera tigris altaica.


1 - AMUR BROWN BEARS AND AMUR TIGERS COMPARED - SKULL

Some years ago, Warsaw wrote Ursus arctos berengianus and Ursus arctos lasiotus are one and the same. Ursus arctos beringianus inhabits the Amur River Basin, Sakhalin, Hokkaido and the Southern Kuril Islands. Ursus arctos piscator inhabits the Northern Kuril Islands and Kamsjatka.

The table below, first posted by Warsaw on AVA, is from Baryshnikov (in Aristov and Baryshnikov, 2001). It shows the greatest total skull length in adult males ranges between 373,8 and 447,0 mm. (average 407,84 mm.), whereas the condylobasal length ranges between 347,0 and 423,3 mm. (average 377,03 mm.). Ursus arctos piscator is a larger animal than U.a. berengianus, but the skull is a bit shorter: 

*This image is copyright of its original author

According to Mazak (1983), adult male Amur tigers average 360-370 mm. (say 365 mm.) in greatest total skull length and about 325 mm. in condylobasal skull length. Seen from their perspective, the skull of Ursus arctos lasiotus is about 11-12% longer (greatest total length or gtl). In condylobasal length (cbl), the difference is 16%. The reason why the difference between GTL and CBL in tigers (and all big cats, for that matter) is more pronounced than in bears (40 mm. vs 30 mm.) is the large sagittal crest. In tigers, the crest is a bit longer. For this reason, it projects over the condylae to a greater extent than in brown bear skulls. Compare this skull to the skull of the Amur brown bear in paragraph 5 (below):

*This image is copyright of its original author

Bears have longer skulls because they have a longer maxillary bone (muzzle), but Amur tiger skulls as as wide or wider and they also have a significantly wider rostrum as well as significantly longer and thicker upper canines. In skull weight, however, it's advantage brown bears again, although not by much. The reason is the posterior part of the skull is very robust.

True hunters, in order to save weight, don't want a lot of armour, whereas bears need it because they, in contrast to tigers, can't always escape from danger. Their defence is robustness. This allows bears to take and withstand damage. According to many in the know, male Amur tigers and male Amur bears could compare in strength and claw, but teethwise tigers definitely have the edge.          


2 - AMUR BROWN BEARS AND AMUR TIGERS COMPARED - HEAD AND BODY LENGTH IN A STRAIGHT LINE

Kucherenko wrote adult males of Ursus arctos lasiotus average 196 cm. in total length. It isn't known if they were measured 'over contours' or in a straight line. As most bears are measured 'over contours', it was assumed Kucherenko's brown bears were also measured in this way. What is 196 cm. 'over contours' in a straight line in male brown bears? There's no information on Ursus arctos lasiotus, but in Yellowstone male brown bears 196 cm. 'over contours' was 164-165 cm. in a straight line.  

This is the table with information on Yellowstone male brown bears again. It is about the averages for adults at the bottom: 
  

*This image is copyright of its original author

The table says adult males in Yellowstone average 196,5 cm. 'over contours' and 164,3 cm. in a straight line in total length. But what is a straight line length in male brown bears? When a big cat is measured, the head is positioned in such a way that the top of the skull and the spine constitute a more or less horizontal line. Then markers are placed at the tip of the nose and the tip of the last tail bone. The animal is removed and the distance between both markers is measured in a straight line. This is the length measured 'between pegs' (between the markers).

In bears, however, things are a bit different. The second drawing (see below) clearly says the head of a bear, before he is measured, isn't positioned in the same way as in big cats. This means that not the actual length, but the length of the curve is measured in a straight line (see A1 in the second drawing below). If the head would have been positioned in such a way that the top of the skull and the spine constitute a more or less horizontal line (like in big cats), the bears would have been a bit longer.

I have no clue as to how much longer, but the difference between a measurement taken 'over contours' and one taken 'between pegs' would be greater than in big cats because of the large shoulder hump and the very curved spine typical for bears. If we assume a difference of 4-8 inches between both methods in an average-sized adult male big cat, the average difference would be 8-12 inches in an adult male brown bear. For this reason, 196 cm. 'over contours' could be about 170-175 cm. 'between pegs'.

Still shorter than an adult male Amur tiger, but bears and cats are different animals. Bears have (absolutely and relatively) longer skulls, (relatively) shorter spines, longer limbs and more robust bones than big cats. A bear with a head and body length of, say, 210 cm. measured in a straight line would be a very large animal.

Pictures are better than words. Here's how a big cat should be measured. It's about the position of the head. The top of the skull and the spine constitute a more or less virtual straight line. It is this line that is measured (see the drawing below). If a big cat is measured in this way, it is a measurement 'between pegs'. This is how a big cat should be measured. 

Wild male Amur tigers average 195 cm. in head and body length and 294 cm. in total length (including the tail). The tail should be measured seperately:

*This image is copyright of its original author

This (see the drawing below) is the way brown bears are measured. Most bears are measured 'over contours' (A1). In this post, it is about the straight line length (A). In the drawing, you can clearly see the head of the bear isn't positioned in the same way as in the drawing above. The result is not a straight line measurement of the total length, but a straight line measurement of a bow. The result can't be compared to the straight line measurement of a big cat (see the first drawing). In the first drawing, the straight line length of the big cat really reflects the length of the stretched animal measured in a straight line. If this method would be applied to bears, the head of the bear has to be raised in such a way that the top of the skull and the spine constitute a more or less horizontal line. Then markers have to be placed at the tip of the nose and the insertion of the tail and the animal has to be removed. The distance between both markers has to be measured in a straight line and the result is a measurement taken 'between pegs'. Only if a bear is measured in this way can the result be compared to a measurement of a big cat measured 'between pegs'.  

Wild male Amur bears (Ursus arctos lasiotus) average 196 cm. in total length, probably measured 'over contours' (we are not sure, because Kucherenko didn't tell us in what way the bears were measured). Measured in a straight line (A), they average 164,3 cm. This measurement, however, reflects the straight line measurement of a bow. The reason is the head hasn't been raised. If the head would have been raised and the top of the skull and the spine would have constituted a straight line which would have been measured, the result, most probably, would have ranged between 170-175 cm. For now, I propose 175 cm.      

*This image is copyright of its original author

3 -  AMUR BROWN BEARS AND AMUR TIGERS COMPARED - WEIGHT

Kucherenko's 10 male brown bears (Ursus arctos lasiotus) averaged 264 kg. (583 pounds). Goodrich (personal communication) later confirmed. He said males average 270 kg. (596 pounds). But 3 adult males weighed in 2011 and 2013 were 235 kg. (519 pounds), 180 kg. (398 pounds) and (at least) 165 kg. (364 pounds). The three males, of which two (those of 235 and 180 kg.) were from the Russian Far East, were weighed in late autumn, when bears reach their maximum weight.  

The difference between the averages of Kucherenko and Goodrich on one hand and Seryodkin on the other is difficult to explain. As I really don't know what to make of it, I decided the real average of all adult males could be close to 225 kg., perhaps a bit more. A bit heavier than in Yellowstone, but an average male Amur brown bear seems to be a bit larger than an average Yellowstone male brown bear. They also have longer skulls. 

It could be Kucherenko will be proven right, but the range he gave for males (260-320 kg.), for different reasons, is a bit suspect. A century ago, an average male Amur tiger was 20-30 kg. (46-67 pounds) heavier than an average male today and it possible Amur brown bears also lost mass in the last century. We don't know.   

Talking about Amur tigers. Two centuries ago, forests were more extended, (large) prey animals were more numerous and humans were few and far between in most parts of eastern Russia. A century later, however, the situation had changed dramatically. So much so, that most hunters and naturalists feared for the future. This was between 1900-1920. 

I posted a photograph of the heaviest male accepted by today's biologists (a male shot by Baikov close to the Korean border), but I'm certain this tiger wasn't the heaviest. I've seen larger animals and so did others. My guess is the 560-pound tiger had the best credentials. Biologists like good credentials and peer-reviewed documents, but they seem to forget this is a thing of today. To dismiss information without the correct credentials as gossip is a bit premature.   

Jankowski (in 'The Tiger's Claw') saw animals who outclassed Baikov's male by a margin. His sons, as experienced as they come, shot a very large male in 1943. For me, their Sungari River tiger stands. Same for most records of Baikov. Not saying all old records are impeccable (most are not), but they have to be considered, especially Amur tigers. The reason isn't debates about methods and 'sportsmanship' in old Russia (there never was a debate on methods outside British India, as far as I know), but the size of captive Amur tigers. They, and males in particular, are the largest big cats. Some captive male lions can be very large as well, but the average of captive Amur tigers is unsurpassed. This in spite of their very low numbers and the near-extinction in the thirties and forties of the last century. Amur tigers really walked the edge.  

All in all, it's likely that both brown bears and Amur tigers were a bit heavier a century ago. It's also likely one species was more affected than the other by the destruction seen in the last century (eastern Russia still has many thousands of bears, whereas the number of wild Amur tigers will probably never exceed one thousand again), but it would be difficult to attribute the difference in average size to one factor only. There's, however, no doubt the near-extinction of Amur tigers affected the range of size seen today. Compared to other subspecies, their range in size is remarkably limited. But bears would have showed more individual variation at any rate, I think.


4 - AMUR BROWN BEARS AND AMUR TIGERS COMPARED - EXCEPTIONAL ANIMALS

Large animals usually show more individual variation than small animals. Amur brown bears do not disappoint us in this respect, but wild Amur tigers do in that most adults are very similar in size. Very large males have not been seen in the last decades. The tiger shot near the Sungari River in 1943 might have been one of the last giants about which reliable records exist.

Krechmar thinks there are large males today, as he saw their tracks. I take his word for it, as he is very competent and experienced. For now, however, the longest measured by a biologist ('Maurice') was 309 cm. in total length in a straight line, whereas the 212 kg. young adult male captured in the south of Sichote-Alin ('Luke'), in spite of his modest length (head and body length 183 cm.), is the heaviest.

How about a comparison between exceptional representatives of both species?

In order to get there, I propose to select two of each. Representing the captive Amur tigers, in the blue corner, we have the Duisburg Zoo tiger born in Rotterdam Zoo. At 320 cm. in total length measured in a straight line and estimated at 280-300 kg. in his prime, he probaby was one of the largest. Also in the blue corner and representing the wild Amurs, we have the Sungari River tiger. At 11.6 'over curves' (about 10.10 'between pegs' or 330,2 cm.) and least 660 pounds according to one of the Jankowski's, he was marginally larger than the Duisburg Zoo tiger. A bit unusual, as captive Amur tigers usually are larger than their wild relatives.

In the red corner and estimated at about 400 kg. (882 pounds) in his best years, we have the San Diego Zoo male black grizzly ('Blackie'). Representing his wild relatives and weighing 320 kg., we have the male Kucherenko presented at the top of his table. He could have been 252 cm. in total length 'over contours', meaning he might have been similar to the Sungari River tiger in head and body length measured in a straight line.

At maximum head and body length (220-230 cm. in a straight line for both), the difference between them was 40-80 kg. (89-176 pounds). In average males (195 cm. in head and body length for an adult male Amur tiger and 175 cm. for an adult male black grizzly), the difference most probably would have been about half of that (45-88 pounds). If male Amur tigers average 420-440 pounds (190,51 - 199,58 kg.), male black grizzly's would average somewhere between 465-528 pounds, say 500-520 pounds (226,80 - 235,87 kg.). This means the averages mentioned before (see above) could have been about right, although bears could be a bit heavier.

In order to prevent discussions about larger animals. I read reports about Amur brown bears well exceeding the limits given above. According to poster KTKC (AVA), at least two females in Manchuria well exceeded 300 kg. One of these allegedly was 350 kg. (773 pounds). My guess is some males exceeded 400 kg. (882 pounds) in the recent past. But I also read unconfirmed reports of Amur tigers dwarfing the two tigers mentioned above. One of these, shot in the fifties of the last century, allegedly was 384 kg. (848 pounds), or about twice the weight of an average male today. 

I could continue on freak specimens and countless rumours for quite some time, but decided against it. One has to see an average-sized captive adult male Amur tiger at close range to really appreciate his size. Same for brown bears and lions.                  


5 - A FEW PHOTOGRAPHS, STORIES AND TABLES

a - The difference between Amur and Yellowstone brown bears

The photographs I saw suggest Yellowstone brown bears are a bit more rounded than male Amur brown bears. With rounded, I mean loaded with humps, bumps and curves. Amur brown bears have a longer skull, larger ears and a longer neck. They also seem to be taller at the shoulder than at the hip. Males in particular appear more athletic than their American relatives. Most photographs are from camera traps: 

*This image is copyright of its original author

      

The second bear is a male Amur brown bear:

*This image is copyright of its original author

*This image is copyright of its original author

*This image is copyright of its original author

Here's a few captive Amur brown bears. The first one photograph was taken in a Chinese zoo. There is a fence between the immatures and the adults:

*This image is copyright of its original author

This is the captive San Diego Zoo Amur brown bear of 882 pounds. First posted by Grahh:
 

*This image is copyright of its original author

I've nothing about this giant, but he seems as large as they come. First posted by Warsaw:

*This image is copyright of its original author

b - Amur brown bears and Amur tigers compared - Skeleton

Below, you'll find the skeletons of an Amur brown bear and, for lack of better, a Sunderban tiger. Amur tigers are larger, but the skeletons of all tigers are identical. What do we see?

The tiger, a true hunter, sold everything increasing his weight, whereas the omnivore kept everything that could help him when he has to defend himself. It also helps in other respects:

*This image is copyright of its original author

*This image is copyright of its original author

c - The difference between wild and captive animals 

Wild tigers first. This is the tiger Baikov shot in 1911 near the Korean border. At 11.7 'over curves' and 560 pounds, it was a large male:

*This image is copyright of its original author

This one was similar in length (11.6 'over curves'), but bigger all the way. W.J. Jankowski, who was there when the tiger was shot, wrote it was the largest Amur tiger he and his brothers had even seen. And they had seen more than anyone. In his letter to V. Mazak (May 8, 1970), he wrote the giant tiger was at least 300 kg. A few days before he was shot (in July 1943), the tiger had killed a large male brown bear of which only the head and one leg remained. The bear undoubtedly contributed to the great weight. It really is a glimpse into the past and one of a kind:

*This image is copyright of its original author

  

Camera trap (L. Kerley):

*This image is copyright of its original author

 

Male tiger 'The professor' (204 kg.) and those who care about him:

*This image is copyright of its original author

Here are some captive Amur tigers. The first one, on the cover of Mazak's great book 'Der Tiger' (third edition, 1983) is 'Amur' from the Prague Zoo. When he died at age 11,5, Mazak measured the tiger himself. In a straight line, he was 220 cm. in head and body length and 319 cm. in total length. Over curves, he was 337 cm. In his prime, he was estimated at 250-260 kg. His height at the shoulder (standing) was 104-105 cm. When weighed directly after he died, he was 192 kg. Remember he had been losing weight for some time as a result of the disease that killed him:

*This image is copyright of its original author

  

The photograph below (in 'Der Tiger', V. Mazak, 1983) also was posted more than once. It shows that captive Amur tigers are more than long and tall. Some males combine great size with robustness and this one had it all. 

Last year, I was in Duisburg. I talked to people who worked in the zoo and showed them this picture. They didn't know about him, as the photograph was taken in the seventies of the last year. Have a good look, as they don't come much bigger. The Duisburg Zoo tiger was 110 cm. at the shoulder (standing) and 210 cm. in head and body length measured 'between pegs' (total length 320 cm.).

The other tiger in the photograph is a full-grown female. They are not as small as you may think. The females in saw in countless zoos often were as long as the male lions they had. I've seen and measured some very long and robust male lions, but animals of 200 cm. in head and body length in a straight line and 550 pounds, at least in Europe, are few and far between. Not so for Amur tigers. The Duisburg Zoo Amur tiger, in his prime, was estimated at 280-300 kg. Similar to the Sungari River tiger shot in 1943:

*This image is copyright of its original author

d - Amur brown bears and Amur tigers - interaction 

There have been many debates on the outcome of an encounter between adult males in the past. That scenario, however, is unlikely. Wild animals know about energy, benefits and costs. They also know about risks. My guess is they wouldn't indulge in risky engagements. 

Also remember that average-sized males of both species are not that different. Male tigers are a bit longer, but male bears are more robust and heavier. Male tigers are faster, more agile and armed with teeth used to kill animals larger than themselves. Because of their speed, their training as a hunter-killer and the ability to surprise other animals, they nearly always determine when and how a bout is going to be fought. Male brown bears know and for this reason prevent problems. 

There are no doubt exceptions to the general rule of mutual avoidance, but in most cases the fight will be brief. Remember a male tiger can and will pull out of the fight when he is overpowered. A bear usually can't. I don't doubt large bears will displace male tigers at times, but I also don't doubt that some male tigers hunt male bears when they are in reach. In my dictionary, 'in reach' means similar-sized bears or just over.

The 170-kg. (375 pounds) bear killed near the Tatibe River (Bromlej, 1965) was killed by a tigress. An average Amur tigress today is 121 kg. (268 pounds), but half a century ago they were a bit heavier (137-138 kg. or 303 pounds). The heaviest wild female I know of was 368 pounds (166,9 kg.), but she was the only one that reached that weight. One has to assume that a male tiger would be capable of a similar feat, but there is, apart from the tiger shot by the Jankowski's in 1943 (the brown bear he killed, according to W.J. Jankowski, was a large old male), no reliable information. For now, we have to assume the two females estimated between 150-200 kg. (331-442 pounds) were the heaviest brown bears killed by Amur tigers.     

Most posters and biologists agree adult brown bears would be too much of an ask for male tigers. Too dangerous, Miquelle thought. Pikunov said male brown bears were definitely not on the menu. But peer-reviewed documents published in the last decade suggest they could be wrong. Both Tkachenko and Kerley (recent studies) found that adult bears are definitely on the menu in most regions in summer. Not saying adult male brown bears are included, but it can't be excluded.  

In most cases, experienced bear hunters (older male tigers) have a clear weight advantage (about a hundred pounds, acoording to B. Schleier), but they obviously do not avoid adult female brown bears. Two fights between male tigers and adult female brown bears lasted up to 20 minutes. Both females were killed. One of the male tigers was injured.
 
Tigers hunting bears would make sense. They prefer to hunt medium-sized and large animals. In India, experienced males hunt large animals when they are present. In Russia, large ungulates are few and far between. Bears, however, are everywhere. I don't doubt tigers prefer to hunt smaller animals, but my guess is subadults, young adults and old bears will not be avoided. Also remember adult males lose up to 30% of their autumn weight during hibernation. An average adult male brown bear of 500-515 pounds could be under 400 pounds in spring. Well within reach, that is. 

If what I saw in captive animals would hold for wild animals, tigers do not fear significantly heavier male brown bears. The aggression I saw was out of this world and I saw it more than once. My conclusion is they have a clear psychological advantage and many trainers agreed. But an all-out can go either way and a male bear can take a lot of damage. I don't think they, as Pikunov thought, will wear a tiger down, but they have a good defence, a very thick neck and powerful fore-arms. One mistake could be enough.

Ursus arctos lasiotus seems to be different from other brown bears. More athletic, more aggressive and more predatory. Pikunov lost friends and collegues to them and in Russia they are considered more dangerous than tigers. If they are different from other brown bears, and I think they are, the reason could be tigers. A timid animal would be meat for a tiger, but a warrior prepared to confront the hunter would stand a chance. Amur tigers are bear tigers, but Amur brown bears are tiger bears.   


6 - MAPS AND TABLES

a - Amur tiger distribution 2011:

*This image is copyright of its original author

b - Amur brown bear distribution and density:

*This image is copyright of its original author

c - Causes of death of male Amur tigers 1970-1994. The scan, unfortunately, is a bit small. For those unable to read the table. In 1972, a male tiger was killed by a bear. In 1981, a 168-kg. male tiger was wounded by a bear. In 1984, a 136-kg. adult male tiger was killed by a wild boar:
 
 

*This image is copyright of its original author

d - Amur tiger mortality 1985-1996. For those unable to read the table. Between 1985-1996, 7 tigers were killed by bears. No details available:

*This image is copyright of its original author

6 - ARTISTS ON TIGERS AND BEARS

a - According to Dr. P. van Bree, V. Mazak (1983) was a talented man. The drawings in his book confirm Mazak was both creative and gifted. As a zoologist living in a state occupied by the Russians for a long time, Mazak, who spoke and wrote Russian, was one of the few who had access to Russian biologists. Although he wrote the drawing was largely based on the descriptions of Baikov, it is likely Mazak, who was in the former Sovjet-Union himself, also talked to biologists, naturalists and hunters with firsthand experience. If there ever was an accurate drawing, it is this one. Encounters between males, however, were only witnessed a few. One of these was Sysoev. I don't know if Mazak and Sysoev met, but my guess is Sysoev would have seen an encounter between males of both species in a slightly different way. Nice drawing by any standard though:  
 

*This image is copyright of its original author

b - Gorbatov's drawings also are interesting. When males engage, animosity seems to be the driving factor. Not food. This is what I saw in captive Amur tigers and my guess is wild tigers wouldn't be different in this respect. For non-hibernating bears ('Schatuns'), however, food would be a major factor. The information I have suggests Schatuns could have been involved in most fights between males.

- A study:

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- the painting:

*This image is copyright of its original author

c - The last one. A very nice summary of this post, I think:

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