Aggression is a symptom, not a diagnosis. A growing body of research indicates that a significant percentage of sudden-onset aggression—especially in older animals—is rooted in organic disease.
: A sudden increase in aggression, hiding, or vocalization is often the first sign of underlying pain, such as arthritis, dental disease, or internal discomfort.
: Learning through consequences. This involves reinforcement (increasing a behavior) or punishment (decreasing a behavior). Modern veterinary behaviorists heavily emphasize positive reinforcement—rewarding desired behaviors with treats or praise—to build trust and cooperation. 2. Ethology and Species-Specific Needs
Habituation occurs when an animal stops reacting to a harmless, repeated stimulus, like traffic noise. Sensitization happens when a stimulus causes an increasingly intense reaction, such as a worsening fear of thunderstorms. Behavioral Signs of Medical Issues