Tom cats (intact male cats) grow those big, chunky cheeks—often called tomcat jowls or “stud cheeks”—mainly because of testosterone, which thickens the skin and muscles around their face and gives them a kind of built‑in armor and status badge.

What tomcat cheeks actually are

  • They are enlarged pads of skin, fat, and muscle along the cheeks and jawline of sexually mature male cats.
  • Vets and behaviorists often call them tomcat jowls, stud cheeks, or shielding, and they are considered a normal secondary sex characteristic in intact males.

The testosterone effect

  • When a male cat reaches sexual maturity, rising testosterone triggers thickening of the cheek tissues and growth of the underlying muscles, making the face broader and rounder.
  • Neutered males, especially if fixed before puberty, usually never develop big cheeks or they shrink over time as hormone levels drop.

Built‑in battle armor

  • In outdoor or territorial toms, these big cheeks act like natural padding that helps protect the face and neck from bites and scratches during fights over mates and territory.
  • The extra bulk can reduce the severity of wounds in those areas, which matters a lot for free‑roaming males that scuffle frequently.

A signal of strength and status

  • Large cheeks make the head look bigger and more imposing, signaling strength, high testosterone, and good overall condition to other cats.
  • Females may see a tom with big jowls as a more competitive mate, while rival males might think twice before challenging a cat that looks that robust.

Not always just “cute chub”

  • Healthy tomcat jowls are usually firm, even, and symmetrical; sudden swelling, redness, heat, or one‑sided puffiness can indicate an abscess, dental disease, or injury that needs a vet check.
  • If a cat’s “big cheeks” appear quickly or come with pain, drooling, or changes in eating, that is more likely a medical problem than normal tomcat cheeks.

Information gathered from public forums or data available on the internet and portrayed here.