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

[peter]

KUCHERENKO

I saw the famous Kucherenko-table in an article written for hunters. American trophy hunters, to be precise. Based on what I read, I'd say it was written to encourage them to visit the Russian Far East. 

Hunters like size. The bigger, the better. For this reason, Kucherenko could have selected large individuals only. Recent research says adult males, like he said, really average 590-600 pounds in the Russian Far East, but the range most probably isn't as limited as in Kucherenko's table (260-320 kg. or 565-722 pounds).

The table below, first posted by Warsaw in AVA, about the size of brown bears in the northeastern part of Russia could be more accurate. The sample is larger and the range is much more outspoken:

*This image is copyright of its original author

 

I know the bears in the table do not quite belong to Ursus arctos lasiotus, but it has adult males only and in size they more or less compare to their relatives in the Russian Far East. Individual variation, as you can see, is very pronounced. Whereas some of them, at least weightwise, are within the predatory reach of male Amur tigers, the great majority is not. A few are very large. 

A good table should have distinctions between age classes, especially in large and long-lived mammals like brown bears. The table Guate today posted about averages in Kodiak brown bears clearly shows the outspoken differences between age classes.

There are different ways to get to age classes. In the thread about male tigers and male brown bears in old AVA, I posted about a paper written by B.P. Zavatsky (1976). He studied skulls and teeth to get to age-based distinctions in brown bears: 

https://www.bearbiology.org/wp-content/uploads/2017/10/Zavatsky_Vol_3.pdf

There's much more where this came from (the internet), including recent articles about skulls of brown bears in Bulgaria and Iran. 

Based on everything I read, I'd say that one has to distinguish between young adults (5-8), adults (9-12), mature adults (13-18) and old adults (> 18) in large brown bear subspecies like Kodiak bears. At the level of averages, the difference between the age groups is considerable. Like tigers, brown bears seem to keep on growing nearly all their life. Skulls of old bears nearly always are larger and heavier than those of younger individuals. 

Male Amur tigers involved in brown bears occasionally attack adolescent males, but I never read anything about tigers preying on young adult males, let alone adults and older males. This although young adult males are not much bigger than mature females. 

According to Kerley, male Amur tigers hunt female brown bears " ... up to the largest and healthiest (individuals) ... " (from her mail to Junglesprout in September 2011). Her observation was confirmed by others. The question is why they do not hunt young adult male brown bears similar in size and weight (150-200 kg. or 330-441 pounds). My guess is it could be a result of a combination of strength and disposition. In the Russian Far East, brown bears are known for their disposition. Pikunov said they're more dangerous than Amur tigers.     

As to posts about bears in this thread. I don't mind good info about bears, provided it's related to the Russian Far East. The reason is Amur tigers, brown bears and Himalayan black bears live in close proximity in southeastern Russia. Info about the way they interact is of interest, that is. Reply