"Like many snakes, milk snakes are generalist predators that eat just about anything they can catch and swallow," herpetologist Trevor Persons tells us in an email. "In general, younger, smaller milk snakes consume smaller prey such as lizards, while older, larger snakes primarily eat small mammals such as mice or voles."
Rodents like to take refuge in barns, capitalizing on the warmth and food they may provide. And where the furry critters go, their predators follow.
According to Persons, the name "milk snake" (sometimes written out as one word) "originated from the mistaken belief that since these snakes were frequently found in or around dairy barns, they were stealing milk from farmers by suckling on dairy cows."
Let the record show that snakes do not naturally consume milk. Let it also show that any real cow would most definitely notice and object to a sharp-toothed reptile clamping down on her udders.
The absurdity of that image was not lost on Karl P. Schmidt, a former curator of herpetology at the Chicago Field Museum. As he pointed out way back in 1922, milk snakes have six rows of needle-like teeth — two on the lower jaw, four on the upper one.
Jabbing these into "a cow's sensitive teat" (Schmidt's words, not mine) probably wouldn't end too well for the snake. It might make an amusing Gary Larson comic, though.