A giant among marine mammals, a male sperm whale weighs between 40 and 60 tons. Smaller females reach a maximum weight of only 18 tons and measure about 35 feet. Both sexes are born with thick gray skin that darkens in color with age. As a whale matures, this thick covering may bear the scars caused by hunters' weapons, fights over dominance, or wounds picked up while defending young. The sheer size of a sperm whale is overwhelming.
Whales communicate with each other by clicking.
This head is actually a sophisticated communications center. This clicking noise is sent and received much like sonar on a submarine. A whale's head is so large that what sounds to researchers like several clicks can actually be just one. The whale can then judge the distance to its next meal in the darkest of waters. Male adults also use loud clicks to announce their presence with authority, while mothers and their young click to stay in communication.