White, Black & Golden Tigers

[Rishi]

(03-16-2019, 01:03 PM)parvez Wrote: Even black tigers must have had low hunting success rates in previous generations . Hence develop more black colour to hunt effectively during the night times. Golden tabby's must be for hunting effectively during day time.

That's not really how evolution works friend. You don't get what you need, rather if you are lucky enough to get what you need then you live long enough to pass it on... or else 
Siberian tigers never had a white coat in the wild, although that'd be very successful in their habitat. But the mutation just didn't happen in them.

*This image is copyright of its original author

Usually this kind of mutations take place because of error while copying the genes, in this case, too thick & numerous stripes. Or too faded stripes for golden tigers.

The following part is my own speculation. 
The recent population crash of tigers during the '80-'90s may have something to do with it. Let me explain why i think so.

Keep in mind these are all recessive genes & even if the genetic change happens in an individual it won't show. Yes, the first tiger to get the white coat's gene may not have been white itself.
Only when two specimens, both carrying the gene mate will their cubs be black or white or golden. Because the gene was out there, this trait of pseudo-melanistic fur occasionally surfaced in Simlipal from time to time, while golden or white tigers hadn't been seen in the wild for past hundred years (1915-Mohan) until both were found in recent years.

Then came the 2 decades of insurgency when tiger numbers were brought down drastically due to poaching. Some of the survivors clearly carried the recessive genes & then their numbers quickly increased back due to ramped up conservation measures.
But now more tigers have those genes because the source population was small, meaning more of the animals are carriers ...like almost all tigers of Ranthambore have Machhli's blood. If she was melanistic, most tiger-cubs being born at Ranth today would be black.

Because Simlipal was hit so bad (fell from almost 100 to a dozen) black tigers are so common there now, more than 10. But there's only 1 golden tiger & 2 white tigers, as numbers in Kazi or Nilgiri didn't crash that hard.

Otherwise just like in black leopards, as long as normal tigers-leopards are equally successful in hunts & passing their genes, the traits due to recessive genes will be seen rarely. Black tigers may have some advantage while hunting in darkness, but other tigers aren't dying of starvation or their cubs aren't reaching adulthood at a lower rate.
Even if some difference exist, it's not much & can be negated by a little hunting/mothering skill. Reply