The World Wildlife Fund estimates that there are more tigers in captivity than are now in the wild. Their figure for wild tigers is about 3,200. The estimate for tigers owned in the U.S. is several thousand, most in Texas where exotic pet ownership is not regulated. It's impossible to know how many tigers are owned as pets in the world due to lack of regulations and breeding practices. Sadly, most of these tigers will die or wind up in sanctuaries due to abuse or ignorance. Tigers and other exotic animals belong in their native habitat, not as someone's trophy pet.
