Does spaying or neutering affect aggression?

• A. Spaying might affect aggression; neutering does not.
• B. Neither spaying nor neutering has any effect on aggression.
• C. Both spaying and neutering eliminate aggression completely.
• D. Neutering might affect the severity and escalation of aggression. Spaying does not.

Answer: (D)

Hormonally driven aggression in dogs is influenced by gonadal hormones, especially testosterone in males. When a dog is neutered, testosterone levels drop, which can reduce the drive behind hormone‑related aggression such as inter‑male conflicts or territory guarding. This can lessen the severity of aggressive acts and may prevent escalation in some dogs. But aggression is multifactorial—learning, socialization, fear, pain, and environmental triggers all play independent roles—so the outcome isn’t guaranteed for every dog.

Spaying removes ovarian hormones (estrogen and progesterone), but the link between female hormones and aggression is less predictable. Consequently, spaying does not reliably change aggression across the board. In practice, neutering can influence the severity and progression of aggression in some dogs, whereas spaying is not expected to have a consistent, predictable effect.