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

[peter]

VIDEOS OF CAPTIVE TIGERS

Although dedicated to wild tigers, this thread also has information about captive tigers every now and then. Here's why.

a - Information on the effect of stress on size

Captive tigers can tell us a bit more about the recent history of wild tigers. Let's take Amur tigers for starters. According to nearly all involved in books, Amur tigers are the largest subspecies. Recent (1992-2005) research, however, says adult males (3 years and over) roughly compare (referring to weight and total length measured 'over curves') to Indochinese tigers. Compared to Indian and Nepal tigers, adult males might lack as much as 60-80 pounds (at the level of averages). This although they do not seem to be shorter.

The question, therefore, is if the size of Amur tigers in the recent past has been exaggerated. If not, the question is why wild Amur tigers are smaller than, say, a century ago. Can captive tigers be used to answer these questions? The answer is yes.  

According to those who studied reliable records, wild Amur tigers declined in size after 1970. Are they really smaller than a century ago?

Amur tigers in European zoos (referring to Studbook tigers only) say yes. All captive Amur tigers descend from wild Amur tigers captured in the late forties, fifties and sixties of the last century. Are they large? Based on what I have and saw, I'd say they are the largest captive big cats. By a margin, I might add. 

Can the difference in size be quantified? Yes. If biologists consistently measure and weigh adult and old captive Amur tigers, that is to say. If this becomes a routine, captive Amur tigers can tell us a bit more about the effect of habitat destruction, poaching, a lack of prey animals and stress. 

If wild Amur tigers make a come-back (again) and gain a few inches and pounds, their captive relatives can also tell us a bit more about the effect of food on growth and growth potential.  

b - Captive tigers can be used to revive populations of wild tigers

- Although the number of wild Amur tigers, as a result of the efforts of the Russians, has increased, the situation might change once again. In humans, you just never know. If the situation in Russia deteriorates for some reason and poverty strikes once more, chances are wild Amur tigers will suffer as well. As a new population bottleneck can't be excluded, captive Amur tigers could be used to revive the wild population.

c - Genes

It's well-known that wild Amur tigers suffered from a population bottleneck, but what about tigers in Sumatra, Malaysia and southeast Asia? It's more than likely tigers in these regions were affected by stress as well. 

We know a population bottleneck has an effect on size, but recent research suggests it could have an effect on individual variation as well. In wild tigers, individual variation is quite outspoken. In wild Amur tigers, however, individual variation seems to be more limited. I'm not saying all of them have green ears, but the limited amount of variation is a clear sign of a problem. A problem that, perhaps, can be solved by re-introducing genes of tigers captured in a period in which individual variation could have been more outspoken.

d - Rewilding 
   
I know many are opposed to rewilding captive big cats, but the arguments used are far from convincing. What I know suggests that rewilding big cats is an option that should be considered by all involved in conservation. 

It could take 1-2 generations to produce a wild lion or tiger, but there's plenty of circumstantial evidence suggesting it can be done. My guess is the time has arrived to start a number of projects in different regions. 

e - Captive Amur tigers

Here's another video of the Odense zoo tiger 'Igor'. It was uploaded in 2015. As 'Igor' perished in that year, the signs of old age (he was born in 2002) and disease are very visible in that he lost most of his muscles and is hardly able to walk. I'll try to contact the zoo in order to find out if the skull was preserved. Here's Igor one more time:  
 
https://www.youtube.com/watch?v=mfP-eQ4uIa0 Reply