“… In the acuity of their visual system, the sensitivity and deftness with which they can manipulate objects, their sociability, chattiness and willingness to deceive, squirrels turn out to be surprisingly similar to primates. They nest communally as multigenerational, matrilineal clans, and at the end of a hard day’s forage, they greet each other with a mutual nuzzling of cheek and lip glands that looks decidedly like a kiss. Dr. Koprowski said that when he was growing up in Cleveland, squirrels were the only wild mammals to which he was exposed. “When I got to college, I thought I’d study polar bears or mountain lions,” he said. “Luckily I ended up doing my master’s and Ph.D. on squirrels instead.””