The narrow-breasted snake-necked turtle is carnivorous (5) (7) (11), with its diet consisting of aquatic insects, small fish, shrimp and other small crustaceans, tadpoles and frogs. This species also consumes carrion. Hatchling narrow-breasted snake-necked turtles are known to feed on aquatic plants (5) (11).
To capture its prey, the narrow-breasted snake-necked turtle retracts its head and neck towards the body, holding them there until unsuspecting prey ventures within striking range. The narrow-breasted snake-necked turtle has an exceptionally fast strike, which is the fastest of all the Chelodina species. Once the narrow-breasted snake-necked turtle has detected its prey, it is able to shoot its head forward in a striking motion with incredible speed, allowing it to catch even fast-moving prey species (2) (5) (6) (8).
Like other reptiles, the narrow-breasted snake-necked turtle is cold blooded and controls its body temperature through a process called thermoregulation. After eating, the narrow-breasted snake-necked turtle can increase the speed and effectiveness of its digestion by basking to increase its body temperature. This species may bask out of the water, on a bank or on woody debris protruding from the water, although it will often float in the warmer surface layer of the water with its limbs spread, slowly paddling with just its head and shell visible (5).
Mating in the narrow-breasted snake-necked turtle occurs during winter and spring (5), with most females nesting in spring and mid-summer, between September and January (5) (9) (14). The female leaves the water to lay its eggs (2) (5) (10), with nests sometimes found as far as 500 metres from the water’s edge (5). Nest sites are usually located in relatively bare areas, free from dense vegetation (2) (5). The female narrow-breasted snake-necked turtle will pick a suitable nesting site and dig a hole in which to lay its eggs, which are then buried (10). The female uses its shell to pat down the earth of the nest site (5) (10), an action known as ‘tamping’ (8) (10).
The female narrow-breasted snake-necked turtle can lay up to three clutches a year, with each clutch usually containing between 8 and 16 elongated white eggs (2) (5). The incubation period lasts between 183 and 222 days (2), although the exact timing of hatching is determined by weather conditions (2) (10). Once the eggs have been buried, the female returns to the water and no further parental care is given to the eggs or hatchlings (10).
The male narrow-breasted snake-necked turtle becomes sexually mature at a carapace length of approximately 14 centimetres, while the female usually reaches maturity at a carapace length of between 16 and 21 centimetres (2) (5). For both the male and female narrow-breasted snake-necked turtle this usually occurs between 7 and 12 years of age (10).