Glossary

Junior cat

The life stage from about seven months to two years, when a cat reaches adult size and sexual maturity and its energy peaks.

Also called: adolescent cat, teenage cat, young cat, cat adolescence

The junior stage runs from about seven months to two years in the older six-stage life-stage scheme. The cat is no longer a kitten but is not yet fully grown in mind or body. Some breeds, such as the Maine Coon, take longer to mature, and may keep growing for three years or more.

Cats reach puberty at around five to nine months. An unspayed female comes into season and an unneutered male may start spraying, roaming and fighting. Ask your vet about the right time for spaying or neutering, since early surgery prevents unplanned litters and some behaviour problems.

Juniors are energetic, curious and sometimes destructive. Expect zoomies, boundary testing, climbing and rough play, see zoomies and play aggression. Give them lots of play, scratchers and puzzle toys, and keep training sessions short and positive.

Move from kitten food to adult food at around a year, though large breeds may stay on a growth diet longer, see kitten food. Weight can climb fast after neutering, so measure portions and ask your vet about food amounts.

Last reviewed November 7, 2026

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Related terms

Kitten A cat in its first months of life, from birth until about six months to a year old, a time of rapid growth, learning and vaccinations. Adult cat A fully grown cat, roughly from two to six years old, in its prime and needing steady care, exercise and a weight-controlled diet. Zoomies Short, sudden bursts of high-speed running and leaping, common in young cats, usually in the evening or early morning. Play aggression Biting and clawing during play that is aimed at people's hands and feet, common in young cats that lack playmates. Kitten food A food with more energy, protein, fat and minerals than adult food, made to support a kitten's fast growth.