The center of a wolf's universe is its pack, and howling is what keeps
them together. Howling increases seasonally during winter months, and
the sound may carry for six or more miles in cold clear air. 

Wolves howl at anytime of the day or night. They howl to call the pack
together before or after a hunt. They howl to locate each other when
separated. And they howl to warn other packs to stay away from their
hunting grounds.

A wolf howls by pointing its nose to the sky and then giving voice to
a single high-pitched sound that rises sharply and then slides down 
in rippling waves.

Wolves have great hearing. They can hear other wolves howling from 
three or four miles away. They can locate mice by the squeals they 
make. Like bats and dolphins, wolves can also hear high-pitched sounds 
well above the human hearing range. They turn their ears from side to
side and the direction their ears are pointing when sound is the 
loudest helps them to determine where its coming from.


It is believed that wolves hunt mainly hunt small prey by sound rather
than that of sight or smell.