Tropidonophis mairii

Tropidonophis mairii, also known commonly as Mair's keelback, the common keelback, and the freshwater snake, is a species of colubrid snake in the subfamily Natricinae. The species is native to Australasia.

Etymology

The specific name, mairii, is in honor of "Dr. Mair", an army surgeon with the 39th Regiment of Foot, who collected the holotype.

Tropidonophis mairii is found in Australia, Indonesia, New Guinea, and Papua New Guinea.

The preferred natural habitats of Tropidonophis mairii are forest, grassland, and freshwater wetlands, at altitudes from sea level to.

Dorsally, Tropidonophis mairii is olive, brown, or blackish, with small black spots, or with black crossbars anteriorly. Ventrally, it is lighter. The subcaudals and often also the ventrals are edged with black. The dorsal scales are strongly keeled, and arranged in 15 rows at midbody.
It resembles the Australian venomous rough-scaled snake.
T. mairii rarely grows over in total length.

Mair's keelback preys mainly on frogs, but also eats small fishes, lizards, and mammals. It is one of the few snakes that can eat cane toads, up to a certain size, without being harmed.

T. mairii is oviparous. Clutch size is 3–18 eggs.