Animal behavior (ethology) is the scientific study of what animals do, including their interactions with each other and their environment. Veterinary science traditionally focused on physiology, pathology, and pharmacology. However, the modern veterinary approach recognizes that —as important as temperature, pulse, and respiration. A change in behavior is often the first indicator of pain, fear, or disease.

In veterinary science, behavior is often the first "symptom." Because animals cannot verbalize pain, veterinarians rely on

Distinguishing between behaviors an animal is born with (instinct) and those it acquires (conditioning, imitation) .