Paleosuchus trigonatus
Schneider's dwarf caiman

Paleosuchus trigonatus is found in both the Amazon and Orinoco river basins, within the forested regions surrounding shallow streams. Their range covers a wide area in South America, from Peru in the west to French Guiana in the east (Ross,1989; Britton, 2001).

This species is found in and around cool, fast-flowing forest streams and rivers, often near waterfalls or rapids. It seems to prefer cooler water than other crocodilians (Ross, 1989; Alderton, 1991; Britton, 2001).

Paleosuchus trigonatus is the second smallest species of crocodilian in the world. Males of this species will grow to a length ranging from 1.7 to 2.3m, while females generally peak at 1.4 meters.

Hatchlings emerge with a golden patch on their heads that disappears as they further develop. Because of this patch, they are often referred to as ‘crowned caimans.’

P. trigonatus and it’s relative, P. palpebrosus are born with brown eyes, as opposed to other crocodilians, which have yellow eyes. Both species also lack a ridge nestled between the eyes that is more typical in the related genera Caiman and Melanosuchus, hence the common name "smooth-fronted" caimans.

As they develop, the skin of P. trigonatus becomes more bony and ridged, and the scutes are very large and sharp, allowing for better protection suited for life on the land. The tail is short, with two rows of scutes that project laterally, giving the appearance of a wider tail. The tail’s heavy ossification and lack of flexibility, coupled with a more pointed snout that aids in reducing water resistance, may help the animal swim in fast currents.

This species has more and larger bony plates in its skin (called osteoderms) than most other crocodilians.

(Alderton, 1991; Ross, 1989; Britton, 2001; Cogger and Zweifel, 1992)

In some crocodilian species the sex of individuals is determined by the temperature they incubated at as eggs. We don't know if this is the case for this species. We know that the eggs must be maintained at 28-32° C for proper development, and their incubation time is much longer than for most other crocodilians (Magnusson 1989).

Little is known about the lifespan of this species, but they very likely can live for more than 25 years (Britton 2001).

Paleosuchus trigonatus is a solitary species, only congregating during the breeding season. Individually, adults will often have territories that they patrol ranging up to 1000 meters along streamsides. The range of this species also overlaps its relative, Paleosuchus palpebrosus, but it's not clear how the two interact.

P. trigonatus adults are often nocturnal, and may spend their days hiding in burrows, hollow logs or other debris near streams. At night the hunt in and around the streams (Ross, 1989; Alderton, 1991; Britton, 2001).

Paleosuchus trigonatus has several dietary stages form birth on up to adulthood. Hatchlings eat aquatic insects and other arthropods. Juveniles, while still eating insects, begin eating other vertebrates, such as small fish, birds and reptiles. Adults do not rely on fish as much as younger kin, since their rigid tails prevent more effective hunting in the open water. At this stage, hunting within the forests becomes more common. Larger mammals, such as porcupines and pacas become the staple food of P. trigonatus.

As terrestrial hunters, these dwarf caimans must cover a wide range in search of food. Because of this, the head is often raised high, while the neck is positioned more vertically, allowing them to track prey more efficiently (Ross, 1989; Alderton, 1991; Britton, 2001).

This species avoids predation with its behavior (hunting at night, hiding in streams, guarding its young). Its bony hide also protects it from attack.

Jaguars eat juveniles, and possibly adults, while coatis and large lizards eat their eggs.

This species is a mid-level predator, eating other smaller animals, but in turn being eaten by other larger species. In fast flowing streams it may be the dominant predator.

Because of its small size and retiring habits, this species is not considered particularly dangerous to people.

Unlike some other crocodilians, the skin of P. trigonatus is too bony to be used for leather, so this species has little commercial value. It is sometimes hunted locally for food, or for the tourist trade (Britton, 2001).

Because of its heavily ossified skin, hunters have largely ignored P. trigonatus. The main threat, however, comes from the pollution of the environment as well as destruction of P. trigonatus habitat due to gold mining activities. International trade in the species is limited, it is listed on Appendix II of CITES (Britton, 2001; WGBH Educational Foundation, 2000).