Average weight of male 450kg(990lbs) and the female 300kg(660lbs). Average length of males are 4,5m(15ft) and females 3m(10ft). They have a life expectancy of about 75 – 110 years.
It is a very large reptile with powerful jaws, four short legs with webbed hind feet, long powerful tail and a scaly hide with rows of ossified scutes running down the back and tail. Coloration is dark bronzeon the upper body, yellowish green with dark patches on the flanks.
Difference between male and female Adult males are longer than the females with a more robust appearance
They inhabit rivers, lakes, marshes and dams. Capable of submerging their bodies with only the eyes and nostrils sticking out. Normally dive for only a few minutes but will stay underwater for up to 30 minutes, if threatened. When inactive, they can hold their breath for up to two hours. While stalking their prey ,they cruise underwater to its victim and then charge out of the water to seize its prey. The majority of their prey die due to drowning by the crocodile. Being unable to chew, they tear of pieces by rapid revolutions of their body which they swallow whole. Their diet consists out of birds, reptiles ,fish and mammals . When on dry land they can walk with their bodies completely of the ground and are capable of speeds of up to 10km/h(8mph). it will travel great distances over land to find alternative water sources during extreme dry periods.
During the mating season, males attract females by sound. Mating takes place during November – December. After burying the eggs, the female will guard the nest for the 3 month incubation period. The sex of the offspring is determined by the temperature in the nest.