Humans are irrational in a whole lot of ways, but nothing quite compares to our love for our dogs. They provide us neither food nor conversation nor, in most cases, protection. What’s more, they cost us a fortune—a big share of the $60 billion Americans spend on all pets per year goes to the 70 million dogs living in 43 million U.S. households.
But never mind. Dogs and humans have created an improbable bond that is nearly as close as the one we share with our own kind. Now, a study in Science reveals one of the reasons the two species love each other so: the secret, it turns out, is in the eyes.