As of November 2026, the black caiman is the largest kind of caiman. It lives in the Amazon, a huge river area in South America, in slow rivers, lakes and flooded land. Big old males can be longer than 5 metres. They can weigh more than 400 kilograms. In one study, researchers measured three black caimans. They averaged 246 centimetres in total length, and their body masses ranged from 31 to 103 kilograms.

Researchers measured crocodilian bites with sandwich transducers and a portable charge amplifier. The transducer sat under the most prominent upper back tooth, on land. They kept the strongest of three to five bites for each animal. Across the 23 kinds of crocodilian measured, bite force strongly matched body size. As of November 2026, the data for the three black caimans show an average body mass of 59 kilograms and a strongest bite of 4,310 newtons. A newton is a unit of force.

Other scientists studied black caiman nests. Black caimans nest every year in the dry season, and the nest work ran in October, November and December of 2013 and 2014. Unlike the spectacled caiman, black caiman females usually build their nests near water. The reserve where they worked is covered by flooded forest. Its water level rises and falls by up to 10 metres in a yearly flood pulse.

To learn who visits a nest, researchers set up camera traps. The cameras took five pictures at 10-second intervals. The researchers recorded whether a caiman was near the nest on each visit. Egg predation was recorded in 32 percent of the 658 black caiman nests. The nests were monitored over two years in a Brazilian reserve. Egg loss in nests was lower when an adult, probably the female, was present near the nest.

A female black caiman lived for 40 years in captivity, according to a longevity database. The data quality is listed as acceptable and the sample size as small. A newborn black caiman is about 30 centimetres long. One source says a black caiman reaches adulthood at around 8 years old or at a length of about 2 metres. A black caiman's home range can be under 1 hectare in the low-water season and grow to 20 hectares in the rainy season. It lives in slow rivers, lakes and flooded land in the Amazon.

Words to know

• transducers: force sensors
• newton: unit of force
• pulse: yearly rise
• hectare: large land area