Bicoloured Stream Snake (non-venomous)

Description: A small water snake, averaging 30-40 cm in total length, but can reach 50 cm. Body fairly stout and cylindrical. Brown above; sometimes with faint pattern of fine black lines. A broad, yellowish-orange lateral stripe on lower sides, sharply demarcated from the brown dorsal coloration by a thin black stripe that extends from eye to tail. Dorsal scales usually weakly keeled. Lateral scales smooth. Head wedge-shaped and somewhat flattened. Labials whitish or yellowish. Nostrils open on top of snout. Ventrals bright yellow in younger specimens; duller in adults.

Habits and habitat: An in habitant of forest streams that have a gentle gradient. Rare in steep cascading streams. Recorded in Hong Kong from 100 m to 450 m. Mostly nocturnal, and may be seen swimming in pools at night. During the day hides under stones at the water¡¦s edge or in shallow stream pools. A shy, inoffensive snake, never attempting to bite. Is sympatric with Paramesotriton hongkongensis, Tropidophorus sinicus, Opisthotropis kuatunensis, O. balteata and Sinonatrix aequifasciata.

Diet: Feeds on small shrimps, crabs and fish; possibly also on tadpoles.

Reproduction: Lays 2-5 eggs among stones close to water in June.

Distribution: Locally common and widely distributed in the north-eastern, central and western New Territories including the Pat Sin Range, Shek Kong, Kadoorie Farm and Botanic Garden, Shing Mun and Tai Lam Chung. Known from southern China (but not from Guangdong) and southern Vietnam.

Diagnostic features: Uniformly light to dark brown above; lower flanks bright yellow; dorsal brown and lateral yellow lines sharply demarcated.