Ever since the announcement of The Sims 4 Cats & Dogs simmers have been wondering how pet aging would function and what options for aging will we get in the game.
SimGuruSarah answered a few questions regarding pet aging, explaining that Cats and Dogs will age naturally (without an option to age them up manually using the birthday cake) and that pet aging options will go along with sim aging options. If, for example, you choose to disable aging for Sims you’ll also be disabling the aging process for your pets as well.
If you disable aging for your Sims then it will also disable aging for Cats & Dogs.
— Sarah Holding (@SimGuruSarah) October 10, 2017
You cannot manually age Pets up. They will age naturally.
— Sarah Holding (@SimGuruSarah) October 10, 2017