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.

O.K., I still don’t like rats, and I’ll never forget the sensation of whiskers brushing my ankles when a rat in Central Park scampered over my feet. There are plenty of reasons to fear rats. They carry diseases like typhus, leptospirosis, hanta virus pulmonary syndrome, rat bite fever, salmonella poisoning, and of course bubonic plague, and they are ravenous Remys every one of them, feasting on our grains and meats, chewing our ratatouille and destroying as much as a third of global food supplies each year. “Over the past century alone,” writes Robert Sullivan in “Rats,” his magisterial history of the urban pest, “rats have been responsible for the death of more than 10 million people.”

Yet our ratly transactions are not all woes and buboes. As the first mammals domesticated strictly for research purposes, scientists say, rats in the laboratory may well have saved at least as many human lives through the years as rats in the alley have taken. Rats are the preferred experimental animal for studies of the heart, kidneys, immune system, reproductive system, nervous system and other body sectors, and recent breakthroughs in manipulating the rat genome may soon allow the rat to displace the mouse as the geneticist’s darling, too.

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 the Massachusetts Institute of Technology 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.