Killer whales are the largest living members of the dolphin family. Males (called "bulls") typically range from 6 to 8 metres long and weigh in excess of 6 tonnes. Females ("cows") are smaller, generally ranging from 5 to 7m and weighing about 3 to 4 t. The largest male killer whale on record was 9.8 metres, weighing over 10 tonnes, while the largest female was 8.5m, weighing 7.5 t. A baby killer whale is called a "calf". Calves at birth weigh about and are about long. The killer whale's large size and strength make it among the fastest marine mammals, able to reach speeds in excess of .