It has a long mane and an even longer body - 10 metres (30ft) from crested head to mirror-scaled tail. But the Ninki Nanka, legendary "killer dragon" of west Africa, continues to prove elusive.

Six people from the Devon-based Centre for Fortean Zoology (CFZ) went to Gambia this month to look for the beast, which has often been "seen" by locals but never captured or photographed. In books it is usually portrayed as a giant lizard or a kind of dinosaur. The team spent a fortnight collecting reports of sightings and traipsing through swamps believed to be the Ninki Nanka's habitat. "Lots of people claimed to us that they knew someone, usually a grandparent or uncle, who had seen the creature," said Richard Freeman, the CFZ's director of zoology. "But very few had seen one themselves."

Folklore could explain the lack of witnesses: anyone who sees the Ninki Nanka is supposed to die within five years.

But Mr Freeman wants to continue the search in Guinea: "People can laugh, but new species are still out there. This year a pig the size of a sofa was found in Brazil."