Hypsiglena torquata
(Night Snake)

General Description:
Night Snakes are smooth scaled snakes with striking bronze/copper colored eyes that have vertical pupils.  These features help distinguish them from Gopher Snakes, which are similarly colored but have keeled scales and round pupils.  Night Snakes have a dorsal coloration that consists of a tan ground color that is marked by contrasting brown saddles and lateral (side) spots.  The darker brown color also extends from the eyes onto the neck and forms a blotch at the base of the head.  This dark eye-line contrasts with the light (white or cream) colored labial area.  Night Snakes have a solid, pearly-white ventral coloration that is usually iridescent.  Night Snakes are mildly venomous (although not dangerous to humans), and when they are threatened they may coil their body and thrust the coils towards the offender.  While in this defensive posture, the head is flattened into a triangular shape.

Night Snakes are small snakes, generally less than 61 cm (24 in.) in total length (Storm and Leonard 1995).

Night Snakes, like most other snakes from Idaho, mate in the spring and lay 3-9 eggs that hatch later in the summer (Storm and Leonard 1995).  The juveniles resemble the adults.

Habitat:
Night Snakes are nocturnal, making them difficult to find.  They can be encountered by turning objects or during the night on desert roads.  These snakes inhabit desert lowlands that generally have a rocky component, although they can be found in areas lacking rocks, provided there are rodent burrows (Storm and Leonard 1995).

Idaho Distribution:
In Idaho, Night Snakes can be found in the southern portion of the state, and northward along the Snake River to Lewiston. From southern British Columbia, Idaho, Colorado, and Kansas, south to southern Baja California and mainland Mexico.

Diet:
Eats mainly lizards and lizard eggs; may also eat small snakes, frogs, insects, and salamanders. Study conducted in southwestern Idaho found diet commonly consisted of side-blotched lizards, their eggs, and anurans.

Ecology:
Nocturnal/crepuscular. Hibernates/aestivates. Most active from April to October in Texas and Pacific Northwest. Major peak in activity occurs in early June in Idaho; activity may be restricted to relatively cool nights. When inactive, generally found under rocks, in crevices, or underground (in Idaho, found under rocks in spring but not in summer). Known to be mildly venomous. Southwestern Idaho study found that females are 50% longer and 3 times the body mass of males.

Reproduction:
Female lays clutch of 2-9 eggs from April to August, depending on range (late June or July in Idaho). Eggs hatch in 7-8 wk. Males may reach sexual maturity in 1 yr.

Conservation:

Status:	Unprotected nongame species
Global Rank:	G5
State Rank:	S3

Important State References:
Diller, L.V. and R.L. Wallace. 1986. Aspects of the life history and ecology of the desert night snake, Hypsiglena torquata deserticola: Colubridae, in southwestern Idaho. Southwest. Natur. 31:55-64.