Helmeted turtle

Pelomedusa subrufa

TAXONOMY

Testudo subrufa Lacepede, 1788, "Indes" [in error; restricted to Cape of Good Hope]. Three subspecies are recognized.

OTHER COMMON NAMES

English: Cape terrapin, helmeted terrapin; French: Roussatre; German: Starrbrust-Pelomeduse; Afrikaans: Gewone water-skilpad.

PHYSICAL CHARACTERISTICS

Small to medium turtles, with a maximum shell length of 13 in (33 cm), and a broad, flattened, brown to olive carapace. The plastron is rigid (i.e., unhinged), and firmly attached to the carapace. A pair of small triangular mesoplastral bones are present between the hyo- and hypoplastra, but they are widely separated.

DISTRIBUTION

Africa from Senegal and Ethiopia to South Africa, Madagascar, southern Saudi Arabia, and Yemen.

HABITAT

Helmeted turtles are semiaquatic, inhabiting ponds, marshes, and streams, as well as temporary rain pools.

BEHAVIOR

These turtles commonly migrate overland between bodies of water, and therefore most frequently are seen on land or basking at the water's edge. When their habitat dries up, they estivate in

the mud until the next rains (which may be longer than a year). They hibernate terrestrially in the ground or under leaves during the winter in southern Africa. Adults feed mostly at dawn or during the night, but hatchlings forage day and night. Helmeted turtles are occasionally very aggressive in captivity.

FEEDING ECOLOGY AND DIET

These turtles are primarily carnivorous, feeding on earthworms, snails, clams, crustaceans, insects, fishes, frogs and tadpoles, small reptiles, birds, mammals, and carrion of any kind. They have even been observed to attack larger prey, such as birds, as a group, as well as to feed on the ticks on the hide of rhinoceroses when the latter enter waterholes. They also occasionally feed on various parts of aquatic plants and the fruits of terrestrial species.

REPRODUCTIVE BIOLOGY

In subtropical environments, courtship and mating occur in the spring. The male chases the female from behind, touching or biting her posterior extremities with his head, and eventually mounting the top of her shell. He extends his head in front of hers, sways it from side to side, and expels water through his nostrils. His longer tail then swings under hers for intromission. The well-formed, flask-shaped nest is constructed in the late spring to early summer, and apparently only one clutch is laid per year. From 13 to 30 oblong, leathery eggs, averaging 1.5 by 0.9 in (38 by 22 mm) are laid in a clutch. Hatching requires 75-110 days, with hatchlings emerging in February to June. This species is known to exhibit temperature-dependent sex determination, with warm temperatures producing females, intermediate temperatures producing mostly males, and still cooler temperatures again producing females.

CONSERVATION STATUS

This species is so widespread across Africa, occupies such a variety of aquatic habitats, and reaches such high densities that human impact has apparently not been extensive. In fact, the construction of ponds and waterholes for livestock and wildlife has benefited this species by providing new habitats.

SIGNIFICANCE TO HUMANS

This species is eaten by some indigenous people, often by roasting the whole animal under hot coals. Some groups believe the blood to have medicinal properties. The turtles are exploited only minimally for the pet trade. ♦

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