January 21 is Squirrel Appreciation Day. Whether you love them or hate them, you have to admit they serve an essential role in maintaining the ecosystem. (And, they’re so darn cute.) Squirrels are great at engaging humans and it could be debated whether those who interact regularly with humans are the trained or the trainee. They are among the most popular animal species to watch; a quick search reveals an official Squirrel Lovers Club and squirrel watching clubs at UConn and Cornell. Part of the charm of these rodents lies in their fearlessness and curiosity about humans as well as the fact that they are especially vocal. Their repertory of…