Although they can reach lengths of up to 20ft, Great Whites average 12-16 feet long (3.7-4.9 m) long and, when mature, females are generally larger than males. The biggest White shark accurately measured was 19'6" and was caught in Western Australia. In 1987, fisherman estimated a shark caught in South Australia to be about 22 to 23 ft and, although it was never accurately measured, its jaw, tooth and fin size suggest this estimation could be true.  There are many accounts of this species reaching sizes of over 30ft, but none of these have been proven. A large adult shark can weigh upwards of 2000 kilograms.