Complex sentence: Some male Canadian red sided garter snakes engage in female mimicry using fake pheromones after emerging from hibernation that attract rival males in a mistaken attempt at mating to cover them and so transfer heat to them.
Split into simpler sentences: Some male Canadian red sided garter snakes engage in female mimicry by producing fake pheromones after emerging from hibernation. This causes rival males to cover them in a mistaken attempt to mate, and so transfer heat to them.