The self-styled "King of Instagram" has come under fire after posting a photograph online showing his friend sitting on a 100-year-old endangered tortoise.

American socialite Dan Bilzerian posted the picture on Instagram to his nearly 21m followers on Tuesday (28 March) as he holidayed in the British Virgin Islands.

It shows a bikini-clad woman astride the Galapagos giant tortoise at Sir Richard Branson's Necker Island.

Bilzerian wrote alongside the photo: "600 lb, 100 yr old Galapagos tortoise, what an awesome animal."

But many of his followers were less than impressed with the snap, pointing out the species is protected and listed as "vulnerable" by the World Wildlife Fund (WWF).

The Galapagos National Parks specifically asks visitors not to touch or otherwise disturb the tortoises.

One user wrote: "[Leave] this creature alone. Why is she sitting on it like a ride?" Another wrote: "You're not that special and you're even dumber than the idiot sitting on that animal!"

A third stated: "Some animals like horses are able to carry people but this poor tortoise is not ... Tortoises are not accustomed to carry people."

Bilzerian, a 36-year-old professional poker player and trust fund beneficiary from Florida, feeds his followers with a regular stream of photos of his high-flying playboy lifestyle.

He posted several photos of his time on Necker Island, including one where he says: "Shoutout to @richardbranson for being rich enough to buy a private island and make it an endangered animal sanctuary."

The 72-acre island, bought by Sir Richard in the 1970s, is said to be home to more than 140 species of animal.

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