The chimp who thinks he's a puppy: Baby abandoned by his mother adopted by giant bull mastiff (who treats him as one of her pack)

Wearing a big nappy, the cheeky chimp embraces its new mum, caressing her ears and looking very content as he takes a snooze against her furry belly.

In another photo the chimp holds grabs an apple in its tiny hands to take a bite.

This chimp is now two and is reported to still be enjoying the company of its adopted canine family.

Animal behaviour experts say dogs are normally frightened of primates, however, this is not the first cross species adoption.

In 2005 a newborn squirrel was discovered in Seattle having been adopted by a pregnant papillon dog called Mademoiselle Giselle.

Incredibly the dog allowed the squirrel to suckle on her beside her puppies.

The same year Owen, a one-year-old hippo, was taken in by Mzee, a 130-year-old giant tortoise, in a Kenyan zoo after the big baby was orphaned.

The tortoise was removed two years later and a female hippo introduced in a bid to kindle a romance for Owen.

Golden retriever Isabella adopted three white Bengal tiger cubs on a US ranch in 2008 – although they were separated for the dog’s own safety when the big cats reached a year old.