Has your cat suddenly started biting or scratching people?

Possible medical causes

• Hyperthyroidism, arthritis, dental disease, and brain or neurological problems can all make a cat more irritable and prone to aggression
• Pain can lead to biting or scratching to avoid touch or movement; assess sudden changes without pressing the body as a test.
• Cognitive decline and sensory decline in senior cats can also make them anxious and prone to misjudging situations, leading to aggression

Possible behavioral causes

• Play aggression: common in kittens or cats without enough playmates, who haven't learned to control the strength of their bite or claws
• Fear/defensive aggression: a reactive response after encountering an unfamiliar person, animal, or sound
• Petting-induced aggression: suddenly biting mid-pet and then jumping away, likely from overstimulation
• Redirected aggression: a cat gets riled up by something it can't reach, and attacks a nearby person or cat instead
• Staring, blocking or chasing: record resources, exits and both cats rather than assigning dominance.
• Territorial aggression: defending territory against a newly introduced cat or a stranger
• Maternal aggression: a mother cat protecting her newborn kittens — a normal instinct
• Seek veterinary and behavioral help for unclear or repeatedly injurious events; do not provoke a repeat.

Initial at-home suggestions

• Rule out medical problems first (especially thyroid, joints, and teeth)
• Record timing, context and visible behavior before and after; mark unseen parts unknown, without a required 30-minute window.
• Watch for warning body language before an attack: dilated pupils, a swishing tail, ears pinned flat
• Never use physical punishment or shout at your cat — this only increases fear and anxiety
• In multi-cat households, if cats attack each other, don't use your hands to separate them — use a piece of cardboard or another barrier instead

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