Sinonatrix annularis

Colubridae, subfamily Natricinae

100 cm

Rare, most sightings occur in northern Taiwan up to 500 m altitude. Endangered.

Taiwan, South China (Fujian, Jiangxi, Zhejiang, Anhuei, Jiangsu, Guangdong, Guangxi, Hainan, Hunan, Hubei, Sichuan).

This snake is small to medium in size; total length up to 106 cm. There are 17-19 (19 at mid-body) rows of scales, which are keeled except for those on the flanks. Head is oval; body is stout and round; tail is moderately long. Eye is medium-sized; iris is dark brown to black, slightly dappled with irregular areas of yellow brown, and pupil is black, round, surrounded by light yellow brown ring, sometimes off center, i.e. toward upper part of eye. Tongue ranges from flesh-colored to red, darkened by diffuse black pigment, fork tips lighter than stem. Upper head is uniform dark gray to gray brown. The labials are yellow to yellow tan, with vertical or oblique black bands at sutures. Upper body and tail are gray to olive brown, with irregularly shaped black designs on sides. The lateral designs may have diffuse white to cream centers, with scattered spots of white or cream nearby, and usually continuous with ventral bands. Ventral head is dirty white to cream; the posterior gulars may possess black margins. Ventral neck is dirty white, tinted with orange which becomes progressively more intense posteriorly; ventral body and tail also bear scattered quadrangular marks of prominent black pigment which are irregularly arranged on sides. Anal scale is divided and subcaudals are paired.

This nocturnal snake inhabits rice paddies, swamps and ponds. It feeds on tadpoles, frogs, and fish. Females give birth to 1-14 neonates in a litter, whose total length is about 20 cm.

Sinonatrix: "Sino" is New Latin for "Chinese"; natrix is Latin for "water snake"; annularis is Latin for "ringed, banded". The Chinese name 赤腹游蛇 (chi4fu2you2she2) literally means "red-bellied (赤腹) swimming snake (游蛇)".