Sneaky Snake Sex

16 April 2021

Mating season is just around the corner for many animals that call the Arb home. For our native garter snake population, mating is quite the sight… and smell. Garter snakes, which are non-venomous, communicate through the release of pheromones. Pheromones are chemical cues that trigger a social response from others in the population; in this case, male and female snakes send out very distinct scents to signal mating season.

Male garter snakes are smaller than the females, and many males will find one female to form a snake ball. This writhing mass of male snakes attempting to mate with the female can get competitive and somewhat toxic. Besides just physical struggle, male snakes sometimes “kiss” the female to induce anoxia (limit her oxygen) in order to reduce struggling and increase her compliance in the mating. This “kiss” is exhaled air containing carbon dioxide instead of oxygen; in extreme cases, this suffocating tactic has resulted in death. Needless to say, please do not model your sexual behavior off of non consensual male garter snakes!

The garter snakes are so eager to get at it after spending all winter burrowed in the ground. Garter snakes have been emerging from their winter homes deep in the Prairie du Chien formation of carbonate rocks, which make up the bluffs in the lower Arb. This particular rock formation has space to wriggle between the bedding planes. Garter snakes are no strangers to crowding—snake dens have been found that house over 5,000 densely packed individual snakes. Keep your eyes peeled for brownish-greenish striped snakes emerging from solid rock the next time you venture out into the Arboretum—it’s quite the sight if you can handle the fright!

—Samara Kroeger ‘21, for the Cole Student Naturalists

A ball of mating garter snakes in the Arb.
A ball of mating garter snakes in the Arb.

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