Dogs begin making noise nearly as soon as they are born, crying in a variety of tones that alert their mother as to whether they are hungry or in pain or simply contented. Between the ages of three to six weeks, dogs begin to bark. Different barks are often used in different situations, some as a warning, others for attention, and some simply in play. Though dogs may growl when playing with other dogs, growling in other situations is typically meant as a warning and a growling dog should not be approached. Other noises that dogs make include a high-pitched yap, usually when they're excited; yelping, typically when they're in pain; whining or whimpering, often a sign of submission and sometimes pain; and howling, which is a long-distance call that is typically given by a dog who is alone and seeking social contact.