Who is the "king" of tigers? - Bengal or Amur

[GuateGojira]

(04-23-2014, 02:14 AM)'Pckts' Wrote: I believe you are absolutely right, Gaute.

Very cool to see evolution up close in these big cats.
Now the next question...
What determines evoloutionary changes, more...
Enviroment or Prey Base

For example, we can say amurs evolved for the prey base, but the prey base evolved from the enviroment that caused it to have denser fur and more fat/muscle.
Very interesting.
Kind of like "which came first, chicken or the egg?"

 

Evolution is a tricky business, but following the path of a species we can get a better idea of how an animal change trough the time.
 
Sunquist et al. (1999) in the book “Riding the tiger”, in chapter 1 (Ecology, behaviour and resilience of the tiger and its conservation needs), they make a pretty good analysis of how the tiger evolved, following the expansion of the great ungulates of Asia, specifically, the deer-boar-bovine species. In the case of the tiger, environment determines adaptation of the species but the evolution itself seems to be more influenced by the prey: they size, density and habitat preferences.
 
About the fur, this seems to be not a particular characteristic from Amur tigers only. For example, in the Aurora Zoo, in Guatemala, we have three tigers all of them a mix of Bengal-Amur. The climate in my city is template but has a few picks of cold and warm. The tigers develop they coats depending of the climate and interestingly, while the two males develop relative heavy coats, the female (a white one) don’t present a large coat change. Other example are those Sumatran tigers that live in USA-Europe zoos, they DO develop heavy coats that make them look like small fluffy Amur tigers. Finally, check all the pictures of wild Bengal tigers with heavy coats in the Terai area and specially in Bhutan, where cold climate is just like that of Russia. In conclusion, the coat is just an adaptation of the climate, not a particularity of a subspecies, Kitchener (1999) show this and stated that the coat pattern is not a good predictor of “subspecies” separation.
 
In conclusion, the prey is the principal trigger for tiger evolution. The secondary factor will be the climate and environmental issues. However, if some natural disaster or a dramatic change happen (like the Toba eruption), then the evolutionary way of tigers can be affected in a great way, but been a very resilient species, tigers can adapt themselves and survive. At this time, in about 2 million years of existence, the only true menace for tiger is the human been.
 

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(04-23-2014, 02:45 AM)'GrizzlyClaws' Wrote: Basically all modern Mainland tigers were descended from the southern population of the Wanhsien tiger around 75000 years ago, they were the survivors after the climate change caused by the Toba eruption.

I just wonder how the common ancestor of the Caspian-Amur tigers ended up being evolved in the Caucasus region.

 

Well, the point is that when the new population of recently evolved China tigers –Panthera tigris amoyensis– (direct descendants of the Wanhsien tiger) began they expansion through the entire east of Asia, about 70,000 years ago, a single population of tigers began to travel through the north-west of China and about 10,000 years, the Caspian/Amur tiger ancestor managed to colonize Central Asia via the Gansu Corridor (Silk Road) from eastern China. Now in this new territory, the tigers adapted to the new habitat and developed all the necessary characteristics proper of the entire north-central Asian tiger population.
 
This new place was full of prey, despite its desert-like habitat, particularly the wild boar (Sus scrofa) that in this area can grow up to 285 kg (Baskin & Danell, 2003). Sunquist et al. (1999) also believe that the wild boar population was the principal influence in Caspian tiger evolution, while the red deer (Cervus elaphus) population was the main influence for the expansion of the tiger trough Siberia and up to the Amur region.
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