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

[WaveRiders]

Peter,
 
nice post, but please allow me a few remarks for the sake of accuracy and some personal unbiased comments.
 
1)
Your assumption of length A in the table of average brown bears morphometric parameters (of a particular North American population and not to be generalized) to be a length between pegs is not correct. First of all the measurement includes the tail. Second it is a distance from tip of tail to tip of nose measured “along side of body”. Although it is not specified, as for A1, to be a distance with measuring tape following a “contour”, it does not appear to be a straight line distance but a curved distance probably not thoroughly matching any contour.
 
Therefore although the contour length A1 is, as you wrote, a head-and-body measurements with tail not included measured along the contour of the head and vertebral column, you overestimate the straight line head-and-body measurements of brown bears in northeastern Siberia provided by the table you showed in your post.
 
However the correct result would amplify the meaning of your consideration concerning the compact build of a brown bear body, an animal who is built like a tank. In spite of this, I would not generalize the concept too much because there is the need to look at much more data to have the full picture and because brown bears in the Russian Far East are reliably reported at much larger body size then that of any tiger.
 
 
Concerning the possible likely outcome of a confrontation between Amur tigers and brown bears in their natural environment, here follow a few of my considerations.
 
2)
You presented a morphometrics table of brown bears of north eastern Siberia (all samples in that table are outside of present and past Amur tiger habitat range) and compare it to North India tigers just very briefly reminding the bear animal to be actually confronted is not the light north eastern Siberia brown bear but the similar size and heavier Ursus arctos lasiotus, a subspecies ranging from northeastern China to southern Russian Far East (Manchuria, Ussuri and Maritime Territories and Okhotsk shore of Siberia). Well, Ursus arctos lasiotus, the brown bear subspecies living in Amur tiger range, is not only much heavier but even a significantly larger subspecies then the form from northeastern Siberia. Apart from reliable body weights from literature, any study of skull size of animals from the area show evidence it is pretty much about the size of the Kamchatka form U. a. piscator (some scientists state it is even larger, although this, assuming it is actually the case, may apply to the population living along the Okhotsk sea coast only).
 
 
3)
I do not digress on confrontation of northeastern Siberia brown bears and Amur tigers as these encounters do not occurr in reality. At the same time in my opinion it is not so difficult to say something sensible on the outcome of possible confrontations between adult Amur male tigers and adult male brown bears in southern Far Eastern Russia (U. a. lasiotus) when looking at data and evidence and analyzing these elements properly and not with the biased eyes I have too much often noticed in discussions by the very most of people who mostly argue on the basis of animal preferences but without deeply understanding what they are talking about. An approach that I instead categorically refuse, hopefully successfully. It is very much obvious to me that you have the potential to analyze matters rather properly.
 
I can state that adult Amur male tigers nowadays weigh on average around 180 kg on the basis of undisputable data of over 40 different individuals I have in my records to date weighed in the last 40 years by scientists. Perhaps in the past they may have averaged 210-215 kg according to my criteria to select the most reliable historical records (sub-sample counted at N>30 of the whole historical records), although it is a bit hard to pool together such a sample in terms of pure generalized statistical criteria. In modern time the maximum weights measured have fallen so far in the range 200-207 kg with a single particularly large individual scaling 225 kg.
 
The brown bear form we are talking about has an average of condylobasal length of skull in adult males ranging from around 360 mm to around 400 mm depending from samples with normal maximum at around 420 mm (and record skulls up to around 430 mm). Greatest skull length averages up to approximately 430 mm depending from sample with maximum up to 455 mm for the largest males (undisputable data from scientific studies). Hunting records do even exceed this last figure. Anyone who has studied bears deeply (and I did it) can understand what these data mean in terms of brown bear body size and mass even more then from the relatively scant reliable weight records. The animals from Amur-Ussuri region are reliably reported weighing on average around 270 kg, as you highlighted, and topping the scale at over 320 kg under normal maximum. The largest individuals killed during the Fall have been reported scaling well in excess of 500 kg (and therefore estimable at least at 400 kg during Spring). Anyone who has studied brown bears and observed them in the wild can fully realize the impact of their enormous strength, power, endurance, weapons, armours as well as of their dominant, indomitable and aggressive attitude of their mind. A big Amur male tiger attempting to predate even just an average adult male brown bear is either a foolish or desperate or both, pretty much like a single Pleistocene lion would have been entering a cave and hoping not to find an adult male cave bear hibernating because even if caught by surprise such a beast would have been much more then a match for him in the very most of circumstances (remember that hibernating modern bears, and likely cave bears as well, are part-hibernators, reducing body temperature, respiratory and heart frequencies, but being able to rapidly re-establish full functionality of all vital organs in case of hibernation interruption).
 
 
4)
Even if a large adult male tiger towered an average adult male brown bear, I do not think it is a distinct advantage for the tiger. The bear is plantigrade and not digitigrade and therefore has a much more stable platform to wrestle, deliver paw blows with more power and pushing / pulling with the head and neck strength while biting. The body build of a brown bear is significantly more adapted to fight then that of a big cat. Comparing animals at similar weight the latter is longer in the lumbar as well as also in the sacral regions because this is what he needs for high jumping and leaping abilities and for high top speed. It is not a feature an animal needs to fight better. It actually penalizes wrestling while fighting. In the far past I have intensively studied dog anatomy and dog breeds and have owned many dogs (still own one) who I loved/love all more then humans. As a very much secondary conclusion emerged from my studies was that all fighting dog breeds and best fighting dogs have and have been naturally selected with relatively short lumbar vertebral section as that proved one of the feature improving the effectiveness of a dog in a fight easing the way forces are transferred from the hind legs to the shoulders and neck (my studies were however of course focused on completely different aims then understanding what makes a dog good in a fight). From my zoological studies and analyses I have computed a ratio between the lumbar vertebral and the presacral vertebral column of tigers at nearly 34 % on average while brown bears at less then 32 %. Cervical area of tigers is also proportionally longer (ca. 25.5 % vs 21.2%). Tigers have therefore a much proportionally longer neck which is not much useful in a fight as well.  On the opposite the thoracic section is significantly shorter in tigers (less then 41 % vs over 47%) leaving in a brown bear more volume for hearth, shoulder and thoracic muscles and lung capacity. Furthermore bears have proportionally larger chest and more robust scapula with a proportionally larger processus articularis and features like the postscapular fossa and the teres major process both wanting in Canids and Felids. Brown bears have very much developed these characters and have significantly proportionally longer and wider scar areas for the teres major muscle, longer deltoid ridge / deltopectoral crest in the humerus allowing more deltoid and pectoral muscles and other features. The result is more thoracic and forepaw muscles volume at a given size. If you combine all the above with the general bone structure of brown bears markedly heavier then that of modern big cats (I do not demonstrate this as it takes too long but please trust me), the final result is an animal significantly more suited for fight then a big cat but in the canine length (however records of upper canines total crown height of Kamchatka and Alaska brown bears measure over 50 mm and 60 mm respectively), biting force at similar body mass, grappling abilities, agility and speed. The brown bear more then compensates these latter handicaps with an evident more solid, compact, powerful, stronger and more armoured body build at similar body mass, with a more stable body platform being plantigrade, significantly more stamina and longer reach due to wider chest and shoulders and proportionally longer forelegs. In terms of claw effectiveness the brown bear definitely does not lack much compared to a tiger as claws from forepaws measuring 150 mm in Alaska specimens and 120 mm in Kamchatka ones have been reported.
 
Even in the very much unlikely case an adult male brown bear would be grounded by an adult male tiger, brown bears are so strong that while fighting they have shown to be able to raise back on their hind legs by pure strength after being grounded by another and heavier / larger bear who was pushing him down with his whole weight and strength and simultaneously biting him. This is a very much remarkable feast of enormous strength. An adult male tiger, significantly lighter then an adult male brown bear on average, would not be so much of a problem to handle even because the bear has a cardiovascular system delivering more stamina then that of a big cat and a tiger cannot definitely kill an adult either male or female brown bear in short order. The only real chance the tiger could have to get at least initially the upper hand in a fight would be to surprise the bear jumping on him from behind and ground him, but the bear sense of smell is exceptionally developed and it is unlikely, although possible, a tiger around would be unnoticed by a wandering bear.
 
 
5)
The brown bear killed by an Amur tiger you showed in the picture in my opinion is clearly not an adult bear and perhaps not even a male. I am a bit amazed a scientist like Mazak did not notice the animal show several dentition characters (wear and colour) as well as feet sole wear (more difficult to judge) typical of a young animal, either a sub-adult or a young adult at most. My statements seem also to be confirmed, for what is possible to ascertain, by the head proportions of the carcass. I therefore suggest that bear was either a sub-adult male / female or a young adult female. I completely rule out him to be an adult male (8-10 year old and older). Maybe the animal was a sub-adult male or a large sub-adult / young adult female, but I remind that the mind of a brown bear 2.5-5 years old even if weighing more then 170 kg is far from being as strong as necessary to fight such a dangerous and powerful animal of similar size like an adult male tiger
 
 
Conclusively, for an adult male Amur tiger (weight range 146-207 / 225 kg) to attack deliberately for predation an adult male brown bear, an animal normally weighing in the range 260-321 kg with largest individuals up to 400 kg or more in the Spring based on skull size and half a ton or more in the Fall, is in my opinion committing a very much almost certain suicide if the action is taken to the end. Tigers are very intelligent predators and I believe the very vast majority of adult male tigers faced by an adult male brown bear either to defend their own kill or to attempt a predation on him make the wise decision to live another day. Maybe occasionally the unexperienced bold individual would have a go on the boar, but if being able to survive the first close encounter, I tend to believe he would never dare to do it again.
 
 
                  WaveRiders
 

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