Clucas, a graduate student in animal behavior at the University of California, Davis, said she first noted this behavior in 2002.
She saw rock squirrels at Caballo Lake State Park in New Mexico licking themselves to apply chewed snake skin to their flanks, tails, and rear ends, which gave them the pungent, musky scent of a rattlesnake.
Yup, they have turned the snakes’ smell against them. Is there no end to their cleverness? The research is being published in Animal Behavior. Unfortunately, it is not open access so I can’t say too much about it. The abstract mentions:
We found that the sequence of body areas licked during application was essentially the same for the two species. We consider three hypotheses regarding the function of this ‘snake scent application’ (SSA): antipredator defence, ectoparasite defence, and conspecific deterrence. To test these hypotheses, we assessed patterns of species and sex/age class differences in application quantity and compared them with patterns reflecting differences in the importance of predation, flea loads and conspecific aggression as sources of selection. We found no species differences in application quantity; however, juveniles and adult females of both species engaged in longer bouts of application than adult males. This pattern of sex/age class differences in SSA supports only the antipredator hypothesis because juveniles are most vulnerable to predation and adult females actively protect their young. We found no evidence to support either the ectoparasite defence or conspecific deterrence hypotheses. Thus, SSA behaviour may be a novel form of chemical defence against predation.
The excerpt contains two interesting points. First the researchers tested several different hypothesis to explain the behavior (and, as the National Geographic article points out, the behavior does have a natural selection component) and were able to rule two of them out. Second, this is another example of chemical warfare in nature.