World’s largest snake gathering: A surprising ‘honeymoon spot’ for 75,000 snakes in Canada

In a quiet corner of Manitoba, Canada, something unusual happens every spring that continues to surprise many visitors and researchers. The frozen ground, which looks completely lifeless for most of the year, suddenly begins to move in a way that feels almost unreal. Thousands of snakes emerge at the same time from underground limestone dens. The scene at the Narcisse Snake Dens is often described as one of the largest natural gatherings of snakes in the world. It is not a small cluster or a rare sighting. Experts suggest that anywhere between 75,000 and 150,000 red-sided garter snakes may gather here during the peak season. What makes it even more striking is that this all happens in a place that can experience winter temperatures dropping below-30°C.The idea that so many snakes survive in such a harsh environment feels almost unbelievable at first. Yet beneath the prairie surface lies a hidden network of limestone sinkholes and cracks. These spaces, formed millions of years ago, stay slightly warmer than the freezing conditions above. It appears that this underground system acts like a natural shelter, allowing the snakes to survive long winters in a state of dormancy. When spring arrives, the entire system comes alive again.At first glance, the Narcisse area looks like ordinary prairie land. There are fields, scattered trees, and open, wind-swept spaces. Nothing about it immediately suggests what lies below. However, experts say the real story begins underground.Here, the rock formation is made up of limestone rock that has been gradually eroded over many years. This has resulted in deep cracks, sinkholes, and underground tunnels. The underground caves lie beneath the frost line and hence will never freeze during harsh winters. For the red-sided garter snake, this has become their vital survival environment.They congregate in large numbers in the cave for hibernation. They will stay inactive in the cave for several months until warm weather returns again. It is a very simple and effective survival mechanism that has lasted for many years now.When spring finally arrives, something remarkable begins. The snakes start to emerge from the dens in large waves. At first, it is only a few individuals. Then hundreds follow. Soon, the ground itself appears to be shifting with life.Observers often describe the scene as overwhelming. Snakes move over each other, across rocks, and through the grass in constant motion. There is no silence in the visual sense. Everything is movement. The snakes are not gathering randomly. But follow instinct, temperature changes, and chemical signals that guide them toward mating grounds and warmer surfaces. One of the most fascinating behaviours seen at Narcisse is the formation of mating balls. These occur when many male snakes surround a single female snake. Sometimes dozens of males may compete for access to one female at the same time.Experts suggest that pheromones play a key role in this process. The female releases chemical signals that attract males, who detect them using a special sensory organ in their mouths. Once they locate her, they compete intensely for mating opportunities. The scene can look chaotic, but it follows a biological pattern. Males attempt to position themselves correctly while others try to push in. If successful, one male mates while others continue searching. It is a short but highly competitive moment in their life cycle.For many years, the snakes faced serious threats while migrating. Highway 17 in Manitoba runs directly through part of their migration path. As a result, thousands of snakes are killed each year by passing vehicles during seasonal movement.Reports from earlier decades suggest that at certain points, as many as 30,000 snakes could die annually in road crossings. Combined with harsh winters, this created a major population risk. Conservation efforts eventually stepped in. Wildlife experts and engineers worked together to build small tunnels under the road. Snow fencing was also installed to guide snakes safely toward these passages. In some cases, scent-based guidance was used to encourage movement through the tunnels. Over time, these measures significantly reduced snake deaths. While losses still occur, the population has stabilised compared to previous decades.The Narcisse Snake Dens remain one of the most unusual wildlife events in the natural world. It is a place where survival, reproduction, and seasonal change all collide in a very visible way. The scale alone is enough to leave a strong impression on anyone who sees it, especially during peak migration periods when thousands gather together in massive writhing mating clusters.Even today, researchers continue to study the behaviour of these snakes. Every spring, the same pattern repeats itself. The ground warms slightly. The snakes emerge. The prairie comes alive for a short time before returning to silence again.