Most snakes move in a forwards direction by zig-zagging along the ground. However, the Straight Snake of Assam, a small brown snake from north-eastern India, always moves in a straight line. Herpetologists believe that the snake is extremely sensitive to the presence of its prey and will stop dead if prey is near. As it travels in a straight line, if it stops, then it appears to be just another stick or small branch and is deemed harmless by the prey.
The Straight Snake lives mainly in trees where it blends in with the surroundings. It can grow to about four feet long and has a vicious bite that will paralyse a large man for two hours, should he be foolish enough to try and pick up the snake and throw it for his dog to fetch. The snake has the ability to stiffen the sinews of its body and birds have been known to perch on a snake, mistaking it for a tree.
This is an extract from the book Animals Evolution Avoided