National park ranger Llewellyn Dixon took several photos of the strange creature.

This strange misshapen creature has many credulous South Africans convinced that aliens are walking among them, and the country's vets sighing in disbelief.

The elongated carcass was found near Nature's Valley, a resort town near Plettenberg Bay in the country's south, the Herald reported.

National park ranger Llewellyn Dixon took several photos of the creature, which locals immediately claimed was extra-terrestrial in origin.

That theory, however, doesn't wash with local vets. Dr Magdalena Braum, of the Crags Veterinary Clinic, said an autopsy showed the corpse was very much from this world.

"Anyone could see it was baby baboon," Times Live quoted her as saying.

Braum told radio station Algoa FM that the animal's strange shape was most likely caused by the mother carrying it around after its death.

"We have seen it quite often in baboon research troops, when females carry the deceased infants sometimes for as long as three to four weeks on their tail section before finally discarding them," she said.

Dixon said many locals still didn't believe the creature was a baboon. "The teeth don't seem like a baboon's teeth, and while the head was slack the legs were still very rigid. People I have told still don't believe it is a baboon."