In a garter snake mating ball, many males compete to mate with a single female, relying on females’ pheromone trails to pursue them. It’s been long known that some males emit female pheromones to put other males off the scent. How does this happen? New research by M. Rockwell Parker and Robert T. Mason, published in The Journal of Experimental Biology, has found that estrogen may play a role: male red-sided garter snakes implanted with estrogen emitted female hormones; their hormones returned to normal after the estrogen was removed. Article link. Via ScienceDaily.