"Has he been eating normally?" Dr. Ross asked, tossing a high-value treat onto the floor without looking at Baron. The dog ignored it.

The synergy between behavior and veterinary science extends far beyond domestic pets.

"Eating fine," Mr. Henderson said. "But he's been sleeping a lot. And he snapped at my granddaughter yesterday when she tried to hug him."

A owner brought in a dwarf hamster biting its cage bars aggressively. The owner wanted behavioral medication. A vet trained in behavior observed the animal's circadian rhythm disruption. Instead of prescribing sedatives, the vet recommended a larger enclosure with deeper bedding and a proper wheel. The "aggression" stopped. The behavior was not mental illness; it was (repetitive, functionless behavior) caused by environmental deprivation.