Two men have been filmed proudly standing on the back of an endangered animal during a holiday to Mexico.
The two men, believed to be a tourist and a tour guide, posed proudly on the back of a whale shark, which is a protected species.
The pictures were taken near Caribbean Sea islands Isla Holbox or Mujeres, which belong to the south-eastern Mexican state of Quintana Roo.
Whale sharks, which typically grow to more than 40 feet long, are protected species in Mexico.
They are harmless to humans and feed on plankton.
Photos of the men riding on top of the mammal have sparked uproar on social media.
One person said: ‘They are uncivilised people who I condemn in the strongest manner.’Cold War sailor's message in a bottle found 50 years later
Another said: ‘The excursion operator and tourist who climbed on that poor animal should be punished.’
The Yucatan Peninsula Regional Commission, which oversees this coastal area, said it is investigating the ‘authenticity’ of the images.
The commission questioned whether the pictures were taken in the region because of the type of rope used.
However the World Wildlife Fund is already working with the community of Isla Holbox, where the pictures may have been taken, over concerns about the whale-watching trips.
The WWF said: ‘Sadly, some guides were allowing tourists to ride the sharks, and WWF was asked to help develop a code of conduct for the new industry.Wildfire sweeps Gran Canaria forcing 4,000 people to evacuate
‘Along with its partners, WWF negotiated with the involved parties to establish regulations that help make tourism profitable without harming the animals.’
Whale sharks are an endangered species because they are hunted for oil from their livers which is used to waterproof boats.
It emerged in 2016 there are just over 7,000 left in the ocean.
The biggest ever measured 61 feet long and they are the largest species of fish.
Shocking video emerged last year showing a scuba diver riding a whale shark off the coast of Indonesia.