Hostile werewolves can only be encountered in the wild through the Dawnguard add-on. Many werewolves in Skyrim are seen in both human and werewolf form, such as the members of The Companions or the Frostmoon Pack on Solstheim in Dragonborn, while werewolves encountered in the wild are always seen in their beast form, with the exception of two random encounters. The Silver Hand faction is known to hunt them and werewolves are often found in their encampments locked in cells (as in Gallows Rock and Driftshade Refuge) you can recognize a Silver Hand base by the presence of werewolf heads on pikes. In Skyrim, several named NPCs are werewolves.
You can become a werewolf through a ritual during The Companions questline. They have a weakness to silver weapons, but are incredibly strong, very fast, and are immune to diseases and paralysis effects.
They are taller and broader than man and mer, and are capable of moving on two limbs or sprinting on all four. Werewolves are monstrous, wolf-like creatures that roam Skyrim.