One of the four wildlife crowns issued by Sierra Leone in 2005, this coin has a legal tender value of $1 in its country of origin. While there are several species of crocodile in Sierra Leone the most common, the Nile crocodile, was chosen as representative on this coin. Crocodiles are large aquatic reptiles that live throughout the Tropics in Africa, Asia, the Americas and Australia. Crocodiles tend to congregate in slow-moving rivers and lakes, and feed on a wide variety of living and dead mammals and fish. Some species, notably the Saltwater Crocodile of Australia and the Pacific islands, have been known to venture far out to sea. They are an ancient lineage, and are believed to have changed little since the time of the dinosaurs. Crocodiles are very fast over short distances, even out of water. They have extremely powerful jaws and sharp teeth for tearing flesh, but cannot open their mouth if it is held closed. Crocodiles are ambush hunters, waiting for fish or land animals to come close, then rushing out to attack. As cold-blooded predators, they can survive long periods without food, and rarely need to actively go hunting. Despite their slow appearance, crocodiles are the top predators in their environment, and various species have been observed attacking and killing lions. The crocodile's bite strength is up to 3000 pounds per square inch, comparing to just 100 psi for a large dog. Crocodiles eat fish, birds, mammals and occasionally smaller crocodiles. The largest species of crocodile, also Earth's largest reptile, is the Saltwater Crocodile, found in northern Australia and throughout South-east Asia.