Pets, like their owners, tend to expand a little over the Christmas period.

The line is a wry seasonal observation: during Christmas, routines loosen and indulgence becomes socially sanctioned, so both people and their animals are prone to weight gain. By pairing “pets” with “their owners,” the remark gently satirizes human self-recognition—owners notice their pets “expanding” while implicitly admitting the same about themselves. The humor depends on the domestic intimacy of pet-keeping and the shared environment (extra treats, richer food, less exercise). It also hints at projection: we often manage pets’ diets as a proxy for managing our own habits, making the pet’s body a mirror for the owner’s excess.