There is a world somewhere between reality and fiction. Although ignored by many, it is very real and so are those living in it. This forum is about the natural world. Here, wild animals will be heard and respected. The forum offers a glimpse into an unknown world as well as a room with a view on the present and the future. Anyone able to speak on behalf of those living in the emerald forest and the deep blue sea is invited to join.
Maybe that is because the tigers in north america and europe are hybrids of unknown ancestry? Just because a tiger has fur, doesn't mean it's a pure Siberian. I say this because tigers have been rare in their home ranges for a long time now, and those in captivity in north America/Europe would be descendants of tigers imported a long while back and from all over Asia.
A good starting point would be measurements from Russian zoos. The tigers there would be of known ancestry, since, like India, they would have never needed importing tigers but simply lift them from the wild.