Appearance 
The Sperm Whale is easy to identify, even though it spends much of its time deep underwater. It has wrinkled skin and a large, square head that makes up as much as one-third of its typical body length of 36 to 59 feet (11 to 18 meters). Although this is about the same length as a Sei Whale, most Sperm Whales weigh much more -- as much as 50 tons (50,800 kilograms) in some cases.