Crocodiles are found in large and small rivers, lakes, mangroves, and in brackish and fresh water. When a baby crocodile hatches, it is just about three quarters of a foot (25-30 cms) in length. In a few years it matures into an adult. Maturity depends upon size rather than on age. Generally males mature slower than females. In the wild, a female will take between 5-7 years to mature whereas males will take 9-11 years. Gharials take longer to mature; about 8-10 years for the female and 12 years for the male. In captivity, such as in the Madras Crocodile Bank, females mature in four years and males in five. The average size for maturity for a Mugger is-male (2 metres) and female (1.6 metres). Males of Gharials and Salties mature at three and a half metres and females at three metres. Mugger crocodiles breed in between February and April. Salties breed in April and Gharials between the last week of March to the second week of April. Breeding depends on environmental conditions. In the breeding season males often fight for the right to court with several females. During courtship each pair may blow bubbles, rub noses, raise their snout and periodically submerge and re-emerge. Different species show different courtship displays. Gharials, for example, often court each other by making a loud buzzing sound. Mating occurs under water with the male mounted on top of the female. The average gestation period is between 35-60 days. The gestation for a Mugger is 35-40 days and for Gharials and Salties, 40-65 days. The temperature at which eggs are incubated and the moisture content of the environment (humidity) influence the sex within the embryo. Crocodiles will either dig a hole about 30 cms deep or pile up leaves to incubate their eggs. They sometime splash water on the nest to control the temperature. In mugger crocs, females are exclusively produced at constant temperature of 28¡C through 31¡C. At 32.5¡C only males are produced. Both sexes in varying proportion are produced at 31.5 to 33¡C. The female guards the nest. At the time of hatching the young start croaking so the mother (sometimes even the father) digs open the nest. Then she cracks some of the eggs with her teeth to set free the young and carries them to the water in her mouth. The adult crocodiles continue to guard the young until they are about 5-7 months old. Crocodiles have many uses in nature's ecosystem. They help keep the environment clean by eating the carcasses that would otherwise rot. They capture the diseased, wounded and weaker prey thus letting only the strongest survive and thus maintaining a healthy population and keeping up the genetic quality of their prey species.