Strictly speaking, there are no rainforest crocodiles in the Amazon Rainforest aside from the odd American or Orinoco crocodile that may from time to time end up in the northern reaches. Generally speaking, the Amazon Rainforest crocodiles are actually caiman in the alligator family. Caiman can reach large sizes and the black caiman rivals the largest crocodile on Earth, the saltwater crocodile of the Indo-pacific realm. You can read more about saltwater crocodiles species in our rainforest crocodiles article.
Black caiman are a top predator in the Amazon Basin and, like other crocodilians, they use ambush tactics to hunt prey. Utilizing the same techniques that worked for their ancestors 200 million years before present, they lay in wait for an animal to approach the water. When ready, they lunge forward grabbing the prey then retreat to the water drowning the unfortunate animal.
Severely hunted in the 1900s for leather, black caiman populations were reduced by 99%. In the 1970s, they were classed as endangered (not helped by the fact that in these bleak times, tourists on some Amazon steam boats would use large caiman as shooting practice). Populations are slowly recovering but are still restricted to a few areas of the Amazon Basin. As black caiman are dominant species, recovering populations displace their smaller spectacled caiman relatives from flooded forest.
Pictured in the header photo, spectacled caiman get their name from a bony ridge in between their eyes. They are also known as the common caiman and are found in most freshwater areas in central and northern South America. During the day they seem to relax, floating leisurely on the surface. Activity increases at night, which is when they feed on birds, reptiles, amphibians, and fish.
Spectacled caiman are very adaptable and despite pressures from hunting they remain common. When people create artificial water areas like reservoirs, this species moves in and sets up home. In these artificial water bodies, these caiman can be found in large numbers. Spectacled caiman also benefited from the hunting of their larger and dominant cousin, the black caiman mentioned above. When black caiman numbers depleted, spectacled caiman moved into their territory. However, as mentioned before, now the black caiman is increasing in numbers its kicking out this smaller species from mutual habitat.
The yellow caiman was previously classed as a subspecies of spectacled caiman, but has since been given full species status. They reach about three metres in length and live in wetlands, lakes, and rivers in south central South America (most notably the Pantanal). This species is also known as piranha caiman in its native range due to their taste for piranha fish. As well as Piranha, they also feed on other fish, small reptiles, and invertebrates, with a preference for snails. The Pantanal Wetlands has the highest population density of crocodilians on Earth.