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

[BorneanTiger]

(08-22-2019, 10:21 PM)BorneanTiger Wrote:

(08-21-2019, 06:57 AM)peter Wrote: 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

I find it strange that zoos in Europe, Russia or elsewhere would have Amur tigers that are descended from wild tigers caught from the 1940's to the 1960's, or at least putative descendants of types of lions that are extinct in the wild like the Caspian tiger (the Barbary and Cape lions), but not even descendants of the Caspian tiger (the last reliable record being from the Babatag Mountains on the border of Afghanistan and Tajikistan in 1998), considering the huge range in Central and Southwestern Asia that it had. It's not like Caspian tigers were never taken captive, in fact, as I mentioned earlier in this thread, the study of Driscoll et al., which proved the Caspian tiger's close relationship with the Siberian tiger, included a Southwest Asian tiger in Moscow Zoo that was caught in the wilderness of northern Iran, with others being wild tigers from Afghanistan, Uzbekistan, Kazakhstan and China, and there are other cases of captive Caspian tigers (at least from Iran and the Caucasus), that are mentioned here, including some that were kept in German zoos in the 19th and 20th centuries:

Caucasian tiger in Berlin Zoo, 1899: https://web.archive.org/web/200708240914...ger-13.htm, http://carnivoractionplans1.free.fr/wild...f#page=180, https://www.tapatalk.com/groups/animalvs...rFBu7K9adB

*This image is copyright of its original author

*This image is copyright of its original author

*This image is copyright of its original author

Soraya the Persian tigress in Hagenback Zoo: http://www.catsg.org/fileadmin/fileshari...n_Iran.pdf 

*This image is copyright of its original author

*This image is copyright of its original author

How is it possible that a Siberian zoo like that of Novosibirsk could have descendants of the South African Cape lion, or European zoos could have Siberian tigers from the 1940's to the 1960's (when their Caspian relatives were still around) or descendants of the Barbary lion (with Moroccan assistance), or that China and South Africa could have captive South Chinese tigers, but that no zoo in Russia, Europe, Asia or elsewhere has at least one surviving descendant of the Caspian tiger, or are there captive tigers of unknown ancestry?

As I mentioned here, after @Lycaon posted a picture of a Cape lion in Hagenbeck Zoo (where Soraya the Persian tigress was hosted in the 20th century), I decided to research Hagenbeck Zoo, and I noticed that it was founded by a man of the same name who imported exotic animals (like his father Carl Hagenbeck Senior), including Amur, Bengal, Indochinese and Sumatran tigers, and Barbary and Cape lions: https://books.google.com/books?hl=ar&id=...on&f=false

Hagenbeck Zoo in 1904: https://mohistory.org/collections/item/resource:148744 

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