Croc Man

When Dr Brady Barr decided to dress up as a crocodile, the disguise needed to be good. Otherwise he was in grave danger of being eaten by the real thing.

The zoologist adopted his bizarre outfit in the hope of getting closer to a colony of Nile crocodiles, which can grow up to 20ft.

His disguise was a prosthetic head attached to the front of a protective metal cage covered with canvas and a generous plastering of hippo dung to mask his human scent. It was 13ft long - average Nile size. The head was made of glass fibre, while the frame of the body was aluminium covered with a sheet of Kevlar body armour.

Thus protected, he crawled on his hands and knees up to the fearsome reptiles, close enough to touch them.

The most dramatic moment in a documentary film about Dr Barr comes when he is approaching the largest croc on the riverbank - and mistakenly makes a sudden movement. It suddenly turns to face him head-to-head. Dr Barr whispers into his microphone: "Oh, the big one is moving towards me. He has his eye on me. I'm really nervous. I've got to back off!"

Ultimately he managed to infiltrate the crocodiles' lair and attach to their tails small hi-tech 'data loggers' which monitor their activity and give scientists biological information such as the temperatures in their dens.

At least one-third of all crocodile species are endangered, and his extraordinary activities have the aim of bringing worldwide attention to their plight.