Ptyas fusca, commonly known as the white-bellied rat snake or brown rat snake, is a species of colubrid snake. It is found in Indonesia, Brunei, Malaysia, Thailand and Singapore.
The white-bellied rat snake prefers forested habitats. They are known to prey on frogs and lizards and fish. It is known to remain still and hold neck erect when disturbed-a threatening posture.
The adults range from brown to brick-red colour on the upper surface. Ventral scales are white to pale yellowish in colour. Thick black stripes on either side of the posterior body and tail is a characteristic feature. Juveniles often greenish in coloration. The pupil is rounded and large.