Rubbing One Out (On a Tree)
Male deer have been observed achieving erections and apparent ejaculation while rubbing their antlers on trees — behavior some researchers interpret as masturbation.
During the mating season (rut), male deer become highly sexually aroused, and researchers have documented an unusual behavior: achieving apparent sexual release while rubbing their antlers.
Male deer regularly rub their antlers on trees and bushes. The primary purposes are: - Removing velvet (the fuzzy covering on growing antlers) - Depositing scent marks - Strengthening neck muscles for combat
However, scientists have observed that sometimes this rubbing becomes rhythmic and intense, coinciding with erections and movements suggestive of ejaculation. Some researchers interpret this as the behavior providing sexual stimulation beyond its other functions, though this interpretation is debated.
This makes sense given deer physiology during rut: - Testosterone levels skyrocket (up to 5x normal) - Males become constantly aroused - They spend much of their time searching for females - Most males don't successfully mate despite being highly motivated
For the many males who don't win mating rights, antler-rubbing may serve as a release valve for intense sexual arousal.
Some researchers argue this isn't true "masturbation" since it may be incidental to scent-marking. Others point out that the behavior shows clear signs of sexual arousal and gratification, meeting a reasonable definition of the term.
Similar behavior has been documented in other antlered species and in animals with horns.