An unexpected ride on the Hippo Express

A baby crocodile mistook a giant hippo for a rock and lay across it to rest in the sun. Photo / PICTURE MEDIA

A baby crocodile thought he'd found the perfect place for a rest in the sun, but his rock turned out to be a hippo.

But the three-tonne beast didn't seem too worried about his passenger and promptly took the crocodile for a 15-minute journey around Kruger National Park in South Africa.

The moment was caught on camera by field guide Richard Millar.

Mr Millar was just snapping the hippo when the crocodile emerged.

"I came across this hippo in the water which at first had a heron on its back," the 21-year-old told Britain's Daily Mail.

"Then all of a sudden this small crocodile crawled up one side of it and sat on its back.

"It must have thought it was a rock in the water and just chilled out on it for a while. They are cold-blooded creatures and need to rest in the sun.

"The hippo didn't seem to mind and did nothing to shake the croc off. It moved a little but the crocodile remained there for about 15 minutes."

Mr Millar said hippos and crocodiles weren't generally rivals, though hippos have been known to attack crocodiles when they feel threatened.

"It was a complete once-in-a-lifetime situation. I am pretty sure that I will never get another photograph like that for the rest of my life."