From The New York Times:
Between reading recent news reports about altruistic behavior in rats and watching the slickly adorable antics of Remy the culinary rodent in this summer’s animated blockbuster, “Ratatouille,” I’ve had a change of heart. My normal feeling of extreme revulsion toward rats has softened considerably, into something resembling … a less extreme form of revulsion.
And though rats have yet to produce an Albert Camus or design a better mouse trap, a host of new behavioral studies makes plain that the similarities between us and Rattus extend far beyond gross anatomy. They’re surprisingly self-aware. They laugh when tickled, especially when they’re young, and they have ticklish spots; tickle the nape of a rat pup’s neck and it will squeal ultrasonically in a soundgram pattern like that of a human giggle. Rats dream as we dream, in epic narratives of navigation and thwarted efforts at escape: When scientists at MIT tracked the neuronal activity of rats in REM sleep, the researchers saw the same firing patterns they had seen in wakeful rats wending their way through those notorious rat mazes.
Rats can learn to crave the same drugs that we do — alcohol, cocaine, nicotine, amphetamine — and they, like us, will sometimes indulge themselves to death. They’re sociable, curious and love to be touched — nicely, that is. If a rat has been trained to associate a certain sound with a mild shock to its tail, and the bell tolls but the shock doesn’t come, the rat will inhale deeply with what can only be called a sigh of relief.