It is a medium-sized aquatic animal similar in appearance and coloration to a tortoise, ranging in size from 2cm (0.8in) when born to 40cm (16in) as an adult, recognised by a red stripe down each side of the head. Almost totally aquatic, only leaving the water to bask on hot sunny days, they hibernate over the winter at the bottom of ponds or shallow lakes where they enter a state of torpor. Feeding on vegetation, insects and small fish, they are reasonably widespread in the UK, being more active during hot weather. They will tolerate other species in their habitat, but will quickly dive underwater when approached making them difficult to catch.
Red eared terrapins are not native to the British Isles, but have become common in most areas due to widespread release of imported pets by the public once it is realised that terrapins in captivity need a lot of care, as they can live to over 40 years. They have a strong bite, resulting in injuries that should be seen by medical staff as soon as possible as they may carry some diseases. They are not thought to be breeding in the U.K., as the mean summer temperature is too low, however there is some possibility that if temperatures rise by a few degrees breeding could start. Note:- Recent news (2001) from a reptile specialist in the South (near Southampton) is that terrapin nests and eggs were found last year, but no hatchlings were found.
Some press reports of terrapins have incorrectly described them as "snapping turtles[?]", a species that look like miniature Alligators, found in the swamps of Louisiana in America, there may however be a few in the U.K. from imported pets (indeed one of nearly 60cm (2ft) was found in an Aldershot Park, Hampshire). They have a very powerful bite being able to inflict serious injury, larger adults being able to crush bone. It is thought that snapping turtles can live to over 100 years.
There is a European turtle species, Emys orbicularis, the European Pond Turtle, similar in shape, size and habit to the Red Eared Terrapin, but with a more rounded head. This species is not found in the UK, but is common in central and southern Europe. Red eared terrapins are members of the group Chelonia, referring to reptiles with a shell, which contains nearly 250 species. In the United States this genus are usually referred to as turtles, however in the UK they are split into Turtles (aquatic), Tortoises (land) and Terrapins (semi aquatic).