Smith's mountain keelback

Smith's mountain keelback (Opisthotropis spenceri), also known commonly as Spencer's stream snake, is a species of snake in the family Colubridae. The species is endemic to Thailand.

Etymology
The specific name, spenceri, is in honor of Mr. F.D. Spencer who collected the type specimen.

Habitat
The preferred natural habitat of O. spenceri is flowing streams.

Description
O. spenceri may attain a total length (including tail) of 60 cm. Dorsally, it is olive-colored. Ventrally it is yellowish white on the body, with gray mottling on the tail. It has smooth dorsal scales, which are arranged in 17 rows.

Behavior
O. spenceri is aquatic and nocturnal.

Diet
O. spenceri preys upon freshwater shrimp, earthworms, fishes, frogs, and tadpoles.

Reproduction
O. spenceri is oviparous.