The mating season of this snake species is always filled with wonder and mystery.
Unusual Aspects of the Mating Season of the Garter Snake
As winter comes to an end and spring arrives, this is the time when garter snakes emerge from their dens to undertake one of the most crucial tasks of their lives: finding mates to breed. Indeed, spring is also their breeding season, and during this time, approximately 75,000 garter snakes gather at Narcisse Snake Dens—a limestone cave system located in Manitoba, Canada.
The mating behavior of garter snakes can reach extreme levels. In some cases, a single female can be approached by over 100 male snakes vying for her attention. These male snakes will pile on top of one another, forming clusters that resemble love balls. Such gatherings often occur in crevices on the ground, leading to scenes where thousands of snakes can be seen congregating in one area.
In spring, garter snakes leave their dens to search for mates. (Photo: Nat Geo)
Jesús Rivas, a reptile researcher from New Mexico Highlands University in Las Vegas, notes that although garter snakes exhibit this crowded behavior to find mates, such behavior only occurs in specific areas. Rivas states that there are no areas in mainland America that witness such large groups of snakes seeking mates.
It is likely that the habitat and climatic conditions influence the phenomenon of garter snakes congregating to seek mates, as their behavior can vary significantly depending on geographical locations. Currently, Rivas and his research team are studying the mate-seeking behavior of garter snakes in New Mexico.
Explaining the Strange Behavior of Female Snakes
In the group mating displays of garter snakes, experts have yet to determine precisely which male snake wins the fertilization race. However, one thing is certain: this process causes pain for the male snakes, which is why females must make careful choices.
During their breeding season, approximately 75,000 garter snakes gather at Narcisse. (Photo: Nat Geo)
One important observation made by expert Michael LeMaster from Western Oregon University in Monmouth during his research on red garter snakes is that the ultimate “decision” lies with the female, regarding when to ‘open’ her reproductive organs to allow males to mate. Females also use contractions of their reproductive organs as a way to control the timing of mating, and they can interrupt the ‘fun’ if the males do not meet their requirements.
Numerous hypotheses exist regarding how female snakes choose their mates from a multitude of pursuing males, but the exact mechanism remains a mystery. According to research led by a team from Wolverhampton, England, headed by Mark O’Shea, it is likely that the strongest or most persistent males in their pursuit may be the ones that win the right to mate with the female, resulting in offspring with higher vitality.
Another factor, according to Rivas, that may influence female choice is the ability to perceive through direct contact. Females will use this sense to distinguish and select male partners. If there is an opportunity to observe a group of snakes during their breeding period from the inside, such as through camera installations, researchers may find more accurate answers to these questions.
Females also use contractions of their reproductive organs to control the timing of mating. (Photo: Nat Geo)
Females do not limit their choice to just one male; in fact, they often mate with multiple partners. However, this contrasts with previous findings that suggest males tend to be loyal to only one fixed partner.
Rivas also adds that male snakes often expend a significant amount of energy searching for females, reflecting their instinctual group mating behavior. He also suggests that this mating behavior, where a female can mate with multiple males—referred to as polyandry—may be the oldest mating strategy among snake species.
Currently, there is no satisfactory explanation for the development of such mating strategies in snakes. One hypothesis posits that through polyandrous relationships, females may store more sperm, providing additional nutrients for themselves.
According to Rivas’s team, a female snake mating with multiple males may be to ensure the production of the healthiest offspring through competition among the sperm, where lesser-quality sperm cannot survive in the genetic race.
The behavior of a female mating with multiple males may ensure the production of the healthiest offspring.
Females have the ability to store sperm in their reproductive organs for several months to years, and it appears that competition continues between previously stored sperm and newly received ‘fresh and strong’ sperm.
Through this behavior, we can see that there are many secrets yet to be uncovered in the reproductive habits of snakes, partly due to their elusive nature and the difficulty of observing them in their natural environment. Nevertheless, the information we have suggests that the mating behavior of snakes has many similarities with that of spiders. In both animal groups, females are often larger than males, and the competition among males to mate with females is fierce, while the females have the ability to control the situation, select partners, and even consume their mates.
However, why two animal groups with a distant evolutionary relationship—sharing a common ancestor millions of years ago, when animal life was still limited—develop such similar reproductive behaviors remains a mystery that needs to be solved.
