Black Caimans are nocturnal and prefer to hunt at night; they depend on their keen sense of sight and hearing to locate their prey. Female Black Caimans breed only once every 2 to 3 years that too during the dry season of December. The breeding season is timed in such a way that the Caimans nest when the water levels fall and the fish are forced to gather in small pools.
The female Caiman builds a nest using soil and vegetation about 1.5 m across and 0.75 m wide in which about 65 eggs are laid. Female Black Caimans nest close to each other and wait for the eggs to hatch. They safeguard the nest and assist the young hatchlings by delicately breaking the eggs using the teeth and transporting the young from the nest to a safe pool. They do so by taking the hatchling in their mouth and dropping them in the pool.
The Black Caiman is the largest predator in its ecosystem. Its technique of feeding involves drowning the food and swallowing it whole because the teeth have evolved to grab the kill and not to rip it.
The Caiman hunt according to their size, the juveniles eat crustaceans and insects before moving on to eating fish like piranhas, catfish and perch. The other prey like turtles, birds and mammals are usually taken when the opportunity arises. Large Caimans take down tapirs, anacondas, deer and even capybaras. The mature Black Caimans have no natural predators but the juveniles fall prey to jaguars.