Packs defend their territory from other, invading packs by howling and scent-marking with urine. The pack is a complex social family, with older members (often the alpha male and alpha female) and subordinates, each having individual personality traits and roles within the pack.

In Yellowstone, average pack size is 11.8 individuals. Worldwide, pack size will depend on the size and abundance of prey. Wolves are highly social animals and live in packs.

Wolves (back) are larger than coyotes (middle) and red foxes (front).