Crocodiles, these reptiles of various dimensions and considered to be extremely ferocious predators, are widespread around the world, yet their proliferation rate is very slow and infant mortality high, making them highly endangered species.
Crocodiles reach sexual maturity at around the age of 8-10, but size is also a decisive factor – in most cases, crocodiles start mating only after their snout has developed completely. The breeding season varies based on the species and the habitat, with freshwater species mating during the dry months of the year, but with saltwater crocodiles preferring the wet season. Mating usually takes place in the water and it is an activity repeated several times during the mating season.
Mating is followed by gestation and the laying of eggs. Gestation usually lasts 2-3 months, with the egg laying taking place in nests. Most freshwater species dig their nests into the soil in sandy areas of the shore, while saltwater species prefer to build elevated nests to protect their young from the ebb and flow. Most crocodiles make test nests prior to laying the eggs. These test nests are abandoned once the most suitable place is found. Females usually lay 35-40 eggs, but some species are known to lay as many as 95 eggs at a time. They are laid at night and the process takes around 30-40 minutes. Incubation lasts around 80 days, but the duration largely depends on temperature conditions, the eggs hatching earlier when the weather is hot. Temperature is the decisive factor when it comes to the sex of the embryos, too – values of 31-33 degrees centigrade usually yield males, while temperatures above that yield predominantly females.
The offspring start calling from the eggs before hatching. The sound they make attracts the female who starts digging out the nest in order to help with the hatching. She also takes the unhatched eggs into her mouth, rolling them and breaking them to help the young come out. After the hatching, the mother carries the tiny crocodiles to the water in her mouth, introduces them into the water, then stays with them for about a year, until the next mating season. They continue communication by means of voice calls.
Young crocodiles are small and extremely vulnerable to attacks by predators. The young of most species are only around 20-25 cm long and they don’t weigh more than 60-90 grams, making them very easy prey not only for other carnivores of the sea, but also for other adult crocodiles (yes, crocs are cannibals, regularly feeding on their own young). Young crocodiles are often attacked and eaten by sea birds, predator fish such as sharks and other species of large lizards. In freshwater habitats, the hippopotamus is one of the biggest enemies of young crocs, and elephants also prey on them, even though they stay away from adult crocodiles. Young crocodiles have so many enemies in their immediate surroundings that only about 1% of them make it to adulthood.