Caimans are members of the family Alligatoridae and the subfamily Caimaninae. They reside in Central and South America and there are several species. The caiman in general is smaller than the alligator and crocodile, maintaining an average length of 1 meter while the black caiman is the exception reaching lengths of up to 4 meters. Caimans can lay up to 40 eggs, but the average is closer to around 20. In the case of the caiman, genes do not determine the sex of the offspring and instead it depends on the incubation temperature. This places a great emphasis on the quality of the nest and the caiman moms build these nests with mud and vegetation. When this vegetation starts to decay it provides heat for the eggs.
Maternal care in reptiles is not common and when present, usually consists of nest guarding or egg incubation. The female caiman takes this a step further, providing care for her offspring after hatching by running a sort of nursery school.
The spectacled caiman (Caiman crocodilus) raise their offspring in co-operative nursery schools, where one females looks after her own young as well as other females. Hatchling mortality has been shown to decrease with the presence of adult females, so this seems to be a successful strategy. In the care of the Yacaré caiman (Caiman yacare) the young of one mother gather at a “dormitory” site near the shore and then move out to the “nursery” site to hunt for insects. All the while the offspring stay nearby their mother. In the morning at the dorm site they will call to her and this may be the cue for the maternal response. The largest population of Yacaré caimans live in the Pantanal region of Brazil and their predators include jaguars and the yellow anaconda. The maternal care may have evolved to protect the young in response to increased predation in the case of the caiman.
