Wolves Home / Gray Wolves of Yellowstone
Wolves are very social animals. They live and hunt
together in groups called packs. A wolf pack is really
just another name for a family of wolves. A pack is
usually made up of an adult male and female wolf and
their offspring of various ages. Pack sizes range
from three to twenty wolves. A wolf pack has a definite social structure and rules of conduct. The pack leaders are the alpha male and female. These two animals are dominant over all the other wolves in the pack. The alpha male and female are the only wolves that breed and produce pups in the pack, and they also get to eat first at kills.
Wolf pups are born in the spring after a gestation period of around 63 days. A female can have anywhere between one and nine pups, but the average litter size is four pups. The pups are born with their eyes closed and are totally helpless. Pups weigh about one pound at birth. The female stays in the den nursing and caring for her pups while the other pack members hunt and bring back food for her to eat.
Wolf pups grow very quickly. By the time their eyes
open, 15 days after birth, they weigh four pounds.
At three weeks they begin to play inside the den.
Two weeks later they weigh 13 pounds and have begun
wandering outside the den under the watchful eye of
their mom. This is when their mother starts to wean
them from milk. She and the other adult pack members
start the pups on solid food by regurgitating semi-digested
meat directly into their mouths or by depositing this
food on the ground in front of the pups. When the
pups get big enough the adults bring pieces of meat
from their kills for the pups to eat. Between the
ages of two and three months the pups leave their den
permanently. Soon after this they begin traveling
and hunting with the pack.
The social structure of the wolf pack changes from year
to year. Wolves in the pack move up and down in the
"pecking order" or hierarchy. A wolf lower
down in the pecking order may challenge an alpha wolf
for pack leadership. If the alpha wolf loses this
challenge, it will likely go off on its own, find another
mate, and start a new pack. Wolves very low in the
pecking order (that are constantly picked on by the
other pack members) may also leave the pack. They
become lone wolves until they either form their own
pack or on rare occasions join an existing wolf pack.