Frog is the common name for amphibians in the order Anura. Adult frogs are characterised by long hind legs, a short body, webbed digits, protruding eyes and the absence of a tail. Most frogs have a semi-aquatic lifestyle, but move easily on land by jumping or climbing. They typically lay their eggs in puddles, ponds or lakes, and their larvae, called tadpoles, have gills and develop in water. Adult frogs follow a carnivorous diet, mostly of arthropods, annelids and gastropods. Frogs are most noticeable through their call, which can be widely heard during the mating season. The distribution of frogs ranges from tropic to subarctic regions, with most of the species found in tropical rainforests. With over 5,000 species described, they are among the most diverse groups of vertebrates. However the declining numbers of certain species of frogs are increasingly giving cause for concern.