According to research published in September 2010, male squirrels masturbate as a form of 'genital grooming' which may have a cleansing effect and reduce the chance of sexually transmitted infection.
In a paper entitled 'The Adaptive Fuctions of Masturbation in a Promiscuous African Ground Squirrel', Jane M Waterman of the University of Central Florida, explaijns that she "examined the factors influencing masturbation by male Cape ground squirrels in light of a number of functional hypotheses".
She found that "masturbation was far more frequent on days of female oestrus and mostly occurred after copulation", but it was not a sexual outlet for males who could not find female squirrels to mate with, as "masturbation rates were higher in dominant males, which copulate more, than in subordinates".
"Female Cape ground squirrels mate with up to ten males in a three-hour oestrus, and by masturbating after copulation males could reduce the chance of infection." The research was conducted in Namibia.