The African helmeted turtle (Pelomedusa subrufa), also commonly known as the marsh terrapin, the crocodile turtle, or in the pet trade as the African side-necked turtle, is a species of omnivorous side-necked terrapin in the family Pelomedusidae. The species naturally occurs in fresh and stagnant water bodies throughout much of Sub-Saharan Africa, and in southern Yemen.
The marsh terrapin is typically a rather small turtle, with most individuals being less than 20 cm (7.9 in) ranging from 15 to 21 centimeters in straight carapace length, but one has been recorded with a length of 32.5 cm (12.8 in). It has a black or brown carapace. The top of the tail and feet are a grayish brown, while the underside (plastron) is yellowish.[citation needed]
The male turtle is distinguished by its long, thick tail. A female tends to have a shorter tail and a broader carapace. A hatchling has a shell size of about 3 cm (1.2 in) in length, and is olive to black in color. It also has two small tubercles under the chin and musk glands in the sides of the carapace.
Uniquely, the genus Pelomedusa does not have a hinged plastron (lower
shell). All the other species in the family Pelomedusidae, however, do have this feature with which they can, using muscles, close the plastron to the carapace to cover the head and front limbs. Unlike many chelonians, the African helmeted turtle is able, when it finds itself upside down, to right itself with a vigorous flick of its long muscular neck.
Recent genetic research suggests that Pelomedusa comprises at least 10 different species, and not only one as previously thought. In the past the physical differences between populations were not regarded as substantial enough to recognise more than one species.
The geographic range of P. subrufa covers a large portion of Africa, from Cape Town in the south to Sudan in the north and Ghana in the west. It has also been found in Madagascar and Yemen.
P. subrufa is a semiaquatic animal, living in rivers, lakes, and marshes, and it also occupies rain pools and fertilized places.[citation needed]
Its preference seems to be for standing water, such as swamps, pans, dams, and lakes. However it is found to a lesser extent along rivers. It is generally absent from regions that are mountainous, forested, or desert.
The African helmeted turtle is an omnivorous eater and will eat almost anything mainly involving aquatic invertebrates, small fish, and vegetation. It may feed on carrion. The fine claws on its feet help it tear its prey apart. Hatchlings will eat tadpoles of many frog species, including Phrynomantis microps.
Groups of P. subrufa have been observed capturing and drowning larger prey such as doves that come to drink; the commotion caused by these group attacks is often mistaken for crocodiles. All food is taken underwater to be eaten.