Squirrels Disguised as Snakes—Are Animals Smarter Than We Think?

"It's a nice example of the opportunism of animals. They're turning the tables on the snake."

Donald Owings, professor of psychology at University of California, Davis.

California ground squirrels and rock squirrels have figured out an interesting way to confuse their predators, according to a new study by researchers at UC Davis. They chew up rattlesnake skin and smear it on their fur so that they smell like THEY are snakes too. This little “lie” is their way of telling the snakes, “don’t bite me, I’m one of you!”

Barbara Clucas, a graduate student in animal behavior at UC Davis, observed both ground and rock squirrels applying snake scent to themselves by picking up pieces of shed snakeskin, chewing it and then licking their fur.

Adult female squirrels and juveniles apply snake scent more often than adult males, which are less vulnerable to predation by snakes, Clucas said. The scent helps to mask the squirrel's own scent, especially when the animals are asleep in their burrows at night, and to persuade a snake that only another snake is in the burrow rather than a tasty snack.

The squirrels are not limited to the use of shed snake skins, said Donald Owings, a professor of psychology at UC Davis who is Clucas' adviser and an author on the paper. They also pick up snake odor from soil and other surfaces on which snakes have been resting, and use that to apply scent. Other rodents have been observed using similar behavior.

Is this research an indication that animals in general might be a lot more intelligent than we give them credit for? Possibly. But there’s more to it than that, Owings told The Daily Galaxy. At the very least is shows just how resourceful animals can be.

“To make that judgment [of intelligence], we’d need to explore the details of how this scent application behavioral system gets put in place in each individual and how it works – how internally guided is it; is there any evident that individual squirrels refine scent application depending on its consequences; etc,” Owings told The Daily Galaxy.

“But it does seem to me to provide general evidence of the complexity and opportunistic nature of biological processes, e.g., by showing that an evocative stimulus like the odor of a dangerous snake is a resource that can be exploited by other animals to whom it might prove useful. This evolutionary and developmental opportunism is a key feature of organisms."

Snake-scent application is one of a remarkable package of defenses that squirrels use against rattlesnakes, Owings said. In earlier work, Owings' lab has found that squirrels can: heat up their tails to send a warning signal to rattlesnakes, which can "see" in the infrared; assess how dangerous a particular snake is, based on the sound of its rattle; and display assertive behavior against snakes to deter attacks. In addition, work by Owings' colleague, psychology professor Richard Coss, has demonstrated that these squirrels have evolved resistance to snake venom.

So are these defensive tactics solely “instincts” developed through evolutionary means, or are they learned behaviors that parents teach their offspring. Did some squirrel just go out one day and figure out that rubbing snakeskin on it's body was a good idea, for example? That would certainly imply some pretty advanced thinking. Owings shared his educated theory on how squirrels developed this technique.

“The question of the role of learning in development of this system is a very interesting one. I don’t doubt that learning of some sort is important, but the relationship between these squirrels and snakes is evolutionarily old and has yielded some remarkable evolutionary adaptations, whose development we know little about in most cases,” Owings told The Daily Galaxy.

“But we do know that young rock squirrels fairly recently emerged from their nursery burrows for the first time attempt to apply snake scent, but don’t do it as proficiently as adults (e.g., they fall over when twisting around to reach their flanks). More broadly, we know that the anti-rattlesnake behavior of California ground squirrels is qualitatively quite similar and complex, but quantitatively different, in pups and adults even on first encounter between pup and snake. So, snake scent application and other aspects of anti-snake behavior appear to develop with a fair amount of complexity in the absence of direct experience with snakes.”

Posted by Rebecca Sato

*This post was partially adapted from a UC Davis news article.

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Link:
http://www.news.ucdavis.edu/search/news_detail.lasso?id=8469

Comments

[B.B.]

Animals are definitely a lot smarter than we sometimes give them credit for. Every species has is own unique set of intelligence traits. Certain species of animals have better memory than humans, or a better sense of direction, or altogether unique senses that we don't even possess. To say that humans are the only intelligent species on the planet is pure arrogant nonsense. We're "smart" enough to go around killing each other in pointless wars and destroy the environment. If that's a sign of intelligence then we'd be better off being "dumb".