Of course their sense of smell also tells them when food or enemies are near. That is one of the ways wolves communicate with their voices. Wolves don't just really howl at the moon. They will howl any time of the day, but are most often heard in the evening because that is when the pack is most active. Sometimes it seems as if they howl just for fun.
Wolves also bark to warn other pack members of danger or to challenge an enemy.
They make a squeaking noise to call the pups and the pups mother will whimper to calm them down. There are usually 4-6 pups born in each litter. Pups are born inside a den. A den is sometimes a small cave or a hole dug out of the ground. The den must be big enough for the mother and her pups.