Why we care to know how squirrels communicate is anyone's guess, but it seems that this research is so important that a robot squirrel is being employed to live amongst the regular squirrel population. In fact, "Rocky" here (named after the cartoon character) is one of a growing legion of robo-creatures designed to study animals in their natural habitat.
Rocky is controlled using a basic computer program and it comes equipped with tiny speakers that play back animal sounds so as not to arouse suspicion amongst the other squirrels. Apparently, tests over the last few years have proven successful in predicting squirrel behaviour, but why they insist on doubling back over the highway into traffic is still a mystery. [USA Today and Yahoo]