PHUKET: This photograph taken at Tiger Kingdom on Phuket has become an Internet sensation with news sites across the US and Europe republishing it.

Just why is the man cupping the tiger's testicles in his hand?

According to tmz.com, UFC fighter Luke Rockhold was ''working on his grip'' in Thailand . . . ''and by that, we mean he grabbed a tiger by the balls - and now the UFC fighter is apologising.''

The 29-year old middleweight posted a pic of the impromptu animal physical online . . . only to issue an apology a short time later.

Rockhold tweeted: ''For those of u who think it was disrespectful I'm sorry. Was so minor just joking around. I was way too scared and would never do anything harmful to any animal.''

The site goes on to note in some surprise: ''Believe it or not . . . there are several tiger parks all over Thailand . . . and taking pics with the giant cats is a super popular thing to do.

''Cupping their balls however, is not.''

The tmz site actually could be accused of much the same mistreatment of wildlife.

When champion golfer Tiger Woods' marriage was breaking up because of his infidelities, it was tmz that pursued every twist and turn and reported in great detail as mistress after mistress of the golfer emerged.

On Phuket, visitors are allowed to enter tiger cages and pat the animals but that's usually the limit.