Verified answer

There are no werewolves in the Sims 3 series as of yet. Hopefully they will bring them back in a future expansion. There is generally only one new "creature" per expansion pack, and the creature that comes with TS3 pets is the unicorn.

http://sims.wikia.com/wiki/Unicorn

Like I said, I guess we'll just have to cross our fingers and hope that werewolves will appear later.

At this time there are no werewolves in Sims 3 or any of the expansion packs. The only special characters are - vampires (Late Night) - mummies (Adventures) - playable ghosts (Base Game) - imaginary friends (Generations) - SimBots (Ambitions) - and Unicorns (Pets). Also there as been no announcement for future expansion packs having werewolves at this time.