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).
Biogeographic Regions: neotropical (Native )
Distribution: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Surinam, Venezuela. Much overlap with Paleosuchus palpebrosus, but not as extensive southwards (probably due to a decreased cold tolerance in comparison with P. palpebrosus).
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)
Range length: 2.3 (high) mm.
Other Physical Features: ectothermic ; bilateral symmetry
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).
Range elevation: 0 to 1300 m.
Habitat Regions: tropical ; terrestrial
Terrestrial Biomes: forest ; rainforest
Aquatic Biomes: rivers and streams
Other Habitat Features: riparian
Habitat and Ecology
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).
Animal Foods: birds; mammals; reptiles; fish; insects; terrestrial non-insect arthropods
Primary Diet: carnivore (Eats terrestrial vertebrates, Piscivore , Insectivore , Eats non-insect arthropods)
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.
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.
- anacondas (Eunectes)
- jaguars (Panthera onca)
- coatis (Nasua nasua)
- large lizards (Squamata)
This list may not be complete but is based on published studies.
Known prey organisms
This list may not be complete but is based on published studies.
Life History and Behavior
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).
Status: captivity: 16.3 years.
Lifespan, longevity, and ageing
Not much is known about courtship and mating in this species. Unlike many other crocodilians, they do not use loud calls to locate mates. Adults are very territorial, and males may chase off potential rivals.
Paleosuchus trigonatus males reach sexual maturity when they have grown to at least 1.4 meters, females at around 1.3 meters. This size is thought to correspond to 10-20 years of age.
Females of this species lay 10-20 eggs, during the late part of the dry season. Hatchlings thus emerge after annual rains of filled nearby streams. Females usually do not usually breed every year.
Eggs incubate in the nest for over 100 days, significantly longer than many other crocodilian species.
(Ross, 1989; Magnusson, 1989; Alderton, 1991)
Breeding season: Breeding takes place during the final part of the dry season.
Range number of offspring: 10 to 20.
Range gestation period: 115 (high) days.
Range age at sexual or reproductive maturity (female): 10 to 20 years.
Range age at sexual or reproductive maturity (male): 10 to 20 years.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; fertilization (Internal ); oviparous
Females build mound nests of decaying vegetation, and lay the eggs inside. They often build their nests next to termite mounds, apparently taking advantage of the heat generated by the nest. Sometimes they'll build on an old nest site, even if the termite nest is dead. Apparently the heat from the decaying vegetation in the nest is sufficient to incubate the eggs properly. This is the only species of crocodilian that nests around termites this way. The behavior may help compensate for the lack of heat from sunlight, in the shady forest habitat these animals live in (Magnusson 1989).
Mothers guard their nests until the eggs hatch, and protects her hatchlings in the water for several weeks. Adults may respond to the distress calls from young caimans that are not their own offspring (Ross 1989).
Parental Investment: female parental care
Molecular Biology and Genetics
Barcode data: Paleosuchus trigonatus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
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Download FASTA File
Statistics of barcoding coverage: Paleosuchus trigonatus
Public Records: 5
Specimens with Barcodes: 6
Species With Barcodes: 1
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).
US Migratory Bird Act: no special status
US Federal List: no special status
CITES: appendix ii
IUCN Red List of Threatened Species: lower risk - least concern
IUCN Red List Assessment
Red List Category
Red List Criteria
- Needs updating
Relevance to Humans and Ecosystems
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).
Positive Impacts: pet trade ; food
The smooth-fronted caiman (Paleosuchus trigonatus), also known as Schneider's dwarf caiman or Schneider's smooth-fronted caiman, is a crocodilian from South America, where it is native to the Amazon and Orinoco Basins. It is the second-smallest species of the family Alligatoridae, the smallest being Cuvier's dwarf caiman, also from tropical South America and in the same genus. An adult typically grows to around 1.2 to 1.6 m (3.9 to 5.2 ft) in length and weighs between 9 and 20 kg (20 and 44 lb). Exceptionally large males can reach as much as 2.3 m (7.5 ft) in length and 36 kg (79 lb) in weight.
The smooth-fronted caiman was first described by the German classicist and naturalist Johann Gottlob Schneider in 1801. The genus name Paleosuchus is derived from the Greek palaios meaning "ancient" and soukhos meaning "crocodile". This refers to the belief that this crocodile comes from an ancient lineage that diverged from other species of caimans some 30 million years ago. The specific name trigonatus is derived from the Greek trigonos meaning "three-cornered" and Latin atus meaning "provided with" and refers to the triangular shape of the head.
The head of the smooth-fronted caiman is similar in appearance to that of the spectacled caiman (Caiman crocodilus), but no bony ridge or "spectacle" occurs between the eyes. The scutes on the back of the neck and the tail are large, triangular, and sharp. It has heavily ossified body armour on both its dorsal and ventral surfaces. The relatively short tail is broad at its base and flattened dorsoventrally in contrast to most species of crocodilians which have laterally flattened tails. The bony scutes on the tail have sideways projections; and the tail is so well armoured, that it is relatively inflexible. This caiman is a dark greyish-brown with mid-brown eyes. Males grow to about 1.7 to 2.3 m (5 ft 7 in to 7 ft 7 in) long, with the largest recorded specimen being 2.6 m (8 ft 6 in). Females do not often exceed 1.4 m (4 ft 7 in). It is a robust crocodilian, strong for its size, and tends to carry its head high with its neck angled upwards.
Distribution and habitat
The smooth-fronted caiman is native to the Amazon and Orinoco Basins in South America and is found in Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela. It inhabits small streams in forested areas where in some cases, the water may be insufficiently deep for it to completely submerge itself. It is seldom seen in open areas and does not usually bask in the sun, even in captivity.
Behaviour and life history
The adult smooth-fronted caiman has cryptic habits and is seldom observed by day because it hides in underwater burrows or may spend much of its time up to 100 m (330 ft) away from water, concealed in dense undergrowth, in hollow logs, or under fallen trees. Males are territorial and females have small home ranges. Adults are semiterrestrial and mainly feed on such animals as porcupines, pacas, snakes, birds, and lizards, consuming few fish or molluscs. Hatchlings feed mainly on insects in their first few weeks, graduating to larger prey as they grow. Juvenile mortality is high, but adult mortality is low, although large carnivores such as the jaguar sometimes prey on them.
Females become mature and start to breed at about 11 years and males at about 20. The female builds a large mound nest out of leaf litter and soil at the end of the dry season or may use a pre-existing nest. A clutch of 10 to 15 eggs is laid and covered with further nesting material. Some heat is generated by the decaying vegetation and good insulation helps to retain this. The nests are often built against the sides of termite mounds and metabolic heat generated by the termites helps to maintain the clutch at a near constant temperature. The eggs need to be maintained at a temperature of 31 to 32°C (88 to 90°F) for the production of male offspring. The incubation period is about 115 days and the female caiman remains near the nest for at least the earlier part of this time, providing protection against predators. During incubation, roots may grow through the nest, and soil from the termite mound may cement the eggs together. This means parental assistance is necessary when the eggs hatch to enable the hatchlings to escape from the nest chamber. Having transported the newly emerged juveniles to a nursery area, the female stays with them for a few weeks after which time they disperse. The female may miss a year before breeding again.
Status and conservation
The smooth-fronted caiman is not extensively hunted because its skin contains many bony scutes, which make it of little use for leather. The animals are collected in Guyana, however, for the pet trade. The main threats to this species are destruction of its forest habitat and pollution of its environment by gold mining activities. Over one million individuals are estimated to remain in the wild, and the species is rated by the IUCN as being of "Least Concern". It is listed on Appendix II of CITES which is designed to limit overexploitation through international trade.
- Crocodile Specialist Group 1996. Paleosuchus trigonatus 2006 IUCN Red List of Threatened Species., IUCN Downloaded on 29 July 2007.
- Paleosuchus trigonatus, The Reptile Database.
- Britton, Adam (2009-01-01). "Paleosuchus palpebrosus (Schneider, 1807)". Crocodilian species list. Retrieved 2013-11-04.
- Ross, Charles A. (ed.) (1992). Crocodiles and Alligators. Blitz. pp. 62, 121–124. ISBN 9781853910920.
- Magnusson, William E.; Lima, Albertina P. (1991). "The ecology of a cryptic predator, Paleosuchus tigonatus, in a tropical rainforest". Journal of Herpetology 25 (1): 41–48. JSTOR 1564793.