The Narcisse Snake Dens is a provincial wildlife management area located in the Rural Municipality of Armstrong about 6 km (3.7 mi) north of Narcisse, Manitoba. The dens are the winter home of tens of thousands of red-sided garter snakes (Thamnophis sirtalis parietalis). These pits are know to house the largest concentration of this particular type of snake in the world. Their winter dens are caverns formed by the area's water-worn limestonebedrock. In the spring, they come up from their dens to the snake pits, where they mate, then they disperse into the nearby marshes for the summer.