* Japanese name: Aodaisho

* Scientific name: Elaphe climacophora

* Description: Rat snakes are long and slender; adults grow up to 110-200 cm. They come in several color varieties but are typically olive-gray or green, with two to four black stripes running down their body from the top of the head.

* Where to find them: These are the commonest snakes in urban areas all over Japan. They can be found near human settlements (sometimes in the ceiling spaces of houses), in barns and in bamboo thickets. They are most active in the morning and evening, and are as much at home in trees and bushes as on the ground. Rat snakes hibernate for three to four months over winter, and from spring they start mating. Seven to 20 eggs are laid in midsummer and develop for about 60 days before the babies hatch. Young snakes have a special scale on the end of their nose called the egg tooth, which they use to break out of their leathery shell. Scales don't grow, so snakes have to shed their skin from time to time as they get bigger -- you might find the molted skin.

* Food: Rat snakes are named for one of the things that they like to eat best -- rats. For this, they are tolerated -- even welcomed -- by people. They also eat mice, frogs, birds and bird eggs. Snakes have special jaws that dislocate when they need to eat really big animals or eggs. They swallow their prey whole, without chewing, often while the animal is still alive. After eating a large meal, fattened snakes will rest and digest the food over several days. Rat snakes are not harmful to humans.

* Special features: In Iwakuni City, Yamaguchi Prefecture, there is a natural population of albino rat snakes. Albino snakes are pure white and have red eyes. Albinos are occasionally seen in the wild, but Iwakuni is the only place in the world where there is a whole population of white snakes. They are thought to bring good luck, because people in the past believed them to be messengers of the good-luck goddess Benzai-ten. This unique albino population is protected by law, but as more houses are being built, the number of snakes is decreasing.