Benefits of female mimicry in snakes

She-male garter snakes exploit the amorous attentions of other males to warm up. Males of several animal species mimic females either in appearance or in the chemical cues they release1,2, and this mimicry has generally been interpreted in terms of alternative mating strategies –– for example, a male that mimics a female may obtain stolen inseminations or avoid aggression from larger rivals3. Our studies of snakes suggest a different explanation, which relies on natural selection rather than sexual selection. Male garter snakes that produce female-like pheromones (she-males) may benefit simply because large 'mating balls' of amorous males form around them, transferring heat to the she-male after it emerges from hibernation and reducing its exposure to predators.