Knowing the gender of your garter snake (Thamnophis sirtalis) isn’t important unless you’re planning to breed it. The only reliable methods of sexing these snakes are cloacal probing or palpating for male reproductive organs, or hemipenes.
Dude Looks Like a Lady
While adult male and female garter snakes look alike, girls are typically longer and bulkier. Mature males average about 16 to 24 inches in length, while females reach about 30 to 36 inches long, depending upon species. While barely noticeable, the male’s tail base is thicker while the female’s tail tapers rapidly to the tip. Both genders reach sexual maturity between 1 and 2 years of age.
Walk This Way
Because they’re not snake eaters, multiple garter snakes can reside in the same enclosure. Separate boys from girls, unless you don’t mind hosting annual love-ins. Cupid smites them in March or April, just as they emerge from hibernation. Males arrive first, eagerly anticipating the arrival of the girls. Hot and bothered, they’re anxious to lead the ladies down the path to Lover’s Lane.
Because the girls lose interest in lovemaking once they’re impregnated, amorous males compete fiercely for feminine favor. Ardent suitors mob the pheromone-scented females upon sight, resulting in a writhing mass of lovers, or mating ball. Males disdain food as females become ravenous while breeding. Unlike most other snakes, garters aren’t egg-layers, so bouncing babies arrive in about 12 weeks.
- California State University, Sacramento Department of Biological Sciences: Snake Gender Determination
- Reptile Channel.com: The Garter Snake
- Ward’s Natural Science: Garter Snakes
- Reptile Channel: Garter Snake Breeding
- Nature North: Garter Snakes in the Classroom
- Holly House Vets: Garter Snake (Thamnophis sirtalis) Care Plan
- Nature North: Snakes Alive -- Manitoba’s Famous Red-Sided Garter Snakes!
- Montana Field Guide: Common Garter Snake -- Thamnophis sirtalis
- Jupiterimages/Photos.com/Getty Images