Direwolf

The direwolf (Canis dirus "fearsome dog") is a carnivorous mammal of the genus Canis, a close relative of the wolf, but larger and stronger.

Appearance
Direwolves can grow as large as ponies. In proportion to their bodies, their legs are longer and their heads are larger than normal wolves. Their muzzles are also longer and more pronounced. Possible colorations include grey with yellow eyes and black with green eyes. Albino direwolves have white fur and red eyes.

Behaviour
Like other wolves, direwolves are social animals and travel in packs. They are efficient solitary hunters as well, and extremely intelligent. Left to its own devices, a solitary direwolf can join a pack of regular wolves, and its larger size can grant it a significant advantage when establishing pack dominance.

Unlike other wolves, direwolves can't form a magical bond with a skinchanger. Direwolves can form easier bonds with werewolves than other wolves.