Iran's complex climate ranges from subtropical to sub polar. It is mild and humid in the Caspian region, but warm and humid in the southern shores. The north-western and north-eastern areas are cold and dry, while the central part has a desertic climate. The heights of Zagros and Alborz enjoy mild weather in summer. Because of this complex climate Iran is famed for having four distinct seasons at the same time, so that one can go skiing in the northern mountains and swimming in the southern waters in the same season. Plant and animal life is of great variety. Wildlife includes leopards, bears, mouflon, ibex, wild ass and wild boars. Studies have revealed the presence of a remarkably wide variety of reptiles like crocodiles and turtels. Some 200 varieties of fish live in the Persian Gulf. Sturgeon is one of 30 species found in the Caspian Sea.