Title

Aspects of the Life History and Ecology of the Desert Night Snake, Hypsiglena torquata deserticola: Colubridae, in Southwestern Idaho

Document Type

Tech Pub

Publication Date

3-31-1986

Journal Title/Publication Source

The Southwestern Naturalist

Volume

31

Issue Number

1

Page Numbers

55-64

Abstract

Seventy-seven desert night snakes (Hypsiglena torquata deserticola) were collected from 1975-1983 in southwest Idaho and analyzed for life history features. Females were nearly 50% longer and three times greater in body mass than males. The sex ratio favored males 2.5 to 1. Mature males captured from April to September had spermatozoa in the ductus deferens but spermatogenesis probably occurred during midsummer. The sexual segment of the kidney tubules was largest in males collected during spring with regression occurring through the summer. Only three clutches of three, four and seven eggs were counted in six sexually mature females. Ovulation and oviposition probably occurred during June, but the possibility of a wider range of ovulation times was not excluded. Males reached sexual maturity at about 29 cm SVL, whereas females were about 40 cm SVL at sexual maturity. Major surface activity began in mid-May and reached a peak in early July. Most captures occurred in rocky habitats and H. torquata deserticola was locally abundant. Lizards (primarily Uta stansburiana) and their eggs were the most common food items, but anurans may also be important prey.

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Aspects of the Life History and Ecology of the Desert Night Snake, Hypsiglena torquata deserticola: Colubridae, in Southwestern Idaho

Seventy-seven desert night snakes (Hypsiglena torquata deserticola) were collected from 1975-1983 in southwest Idaho and analyzed for life history features. Females were nearly 50% longer and three times greater in body mass than males. The sex ratio favored males 2.5 to 1. Mature males captured from April to September had spermatozoa in the ductus deferens but spermatogenesis probably occurred during midsummer. The sexual segment of the kidney tubules was largest in males collected during spring with regression occurring through the summer. Only three clutches of three, four and seven eggs were counted in six sexually mature females. Ovulation and oviposition probably occurred during June, but the possibility of a wider range of ovulation times was not excluded. Males reached sexual maturity at about 29 cm SVL, whereas females were about 40 cm SVL at sexual maturity. Major surface activity began in mid-May and reached a peak in early July. Most captures occurred in rocky habitats and H. torquata deserticola was locally abundant. Lizards (primarily Uta stansburiana) and their eggs were the most common food items, but anurans may also be important prey.