Werewolves will transform back every morning at 6:00, disabling all werewolf-specific interactions until nightfall. Werewolf Sims can even turn other Sims into werewolves with the Savage interaction. Sims gain the Irritate > Grr! interaction which can be used against another Sim regardless of relationship and will lower his or her Bladder need. When outside, a werewolf can also howl to summon wolves to the lot.

A Werewolf Sim can howl when selected, an action which lowers the bladder need of all non-werewolf Sims in the room by half. Their energy shoots up and their hunger need plummets, sometimes making it a good idea to prepare a meal in advance but hunger drop but will never immediately kill the Sim. Once a Sim has become a Werewolf, they will transform every night at 8:00 PM/20:00. Lycanthropy can also be transferred using the savage interaction, though that will leave two bad memories - one of losing a fight to a Sim who initiated the savaging, and another for becoming a werewolf - and it is common for the victim to mourn for a while because of that, despite if that Sim wanted to become a werewolf. Sims can become Werewolves when bitten by the leader of the pack, a large wolf distinguishable by its dark coat, heavy build, and characteristic glowing yellow eyes. Werewolves are Sims who have been infected with Lycanthropy, a life state introduced in The Sims 2: Pets.