Scientists are beginning to understand the medicinal qualities and evolutionary reasons why catnip does more than tickle our cats’ pleasure centers. In this delightful article in the New York Times, Katherine J. Wu unpacks the results of a recent study led by Masao Miyazaki at Iwate University in Japan linking plants to feline health. Researchers now understand that cats–whether big or small–smear themselves with catnip to protect against mosquito bites and heartworm.