Paleosuchus palpebrosus (Cuvier’s Dwarf Caiman)

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Geographic Range

Paleosuchus palpebrosus, Cuvier’s dwarf caiman, is most commonly found in the wetlands of Brazil, French Guiana, Surinam, Guyana, and Venezuela. Widespread throughout the Orinoco and Amazon basins, P. palpebrosus inhabit areas extending from Colombia, Venezuela, and the Guianas south to Sao Paulo and the upper Rio Paraguay in southern Brazil and west to the Rio Pastaza in Ecuador.

Habitat

This species can be found near rivers and inundated savanna areas including the Orinoco and Amazon rivers, as well as those in eastern Paraguay. This species prefers clean, clear, fast-moving streams or rivers in forested areas containing waterfalls and rapids. Paleosuchus palpebrosus mostly inhabit fordable freshwater, avoiding salty, briny waters. It likes cooler waters compared to other caimans. Across inhabited areas, P. palpebrosus has been known to occupy streams of varying sizes, where they are spotted resting near the shorelines. This species is also terrestrial, and has been seen relaxing on piles of small rocks and residing near decaying trees. Likewise, P. palpebrosus is known to dwell in burrows, which are up to 1.5-3.5 meters long. Populations in southern Brazil and Venezuela are limited to waters with very low nutrients. P. palpebrosus can be found resting on rocks, or in shallow water with its back exposed on the surface and its head facing the sun. Preferring colder temperatures, they can survive in cool conditions (as low as 6 degrees Celsius).

Physical Description

This species is the smallest of the alligator family. Males grow to about 1.3-1.5 meters, while the females grow to 1.2 meters. They can reach a mass of about 6-7 kg.

Paleosuchus palpebrosus retain a reddish-brown body color. The dorsal surface is mostly plain and nearly black, while the upper and bottom jaws are covered with several dark and light spots. The tail is marked with encircling bands to the tip. Most of these caimans have brown eyes, but some have also been known to have gold-yellow eyes. P. palpebrosus do not have the same dental formula as other caimans. Most caimans have 5 premaxillary teeth in the upper jaw, but this species only has 4. Scale characteristics allow the differentiations between all other species. P. palpebrosus has 17-20 longitudinal rows on their dorsal and its tail (double crest) has bands of 7-9 rows. Paleosuchus palpebrosus has more osteoderms (bony plates) covering its skin than any other species.

Development

When hatched, the young have almost the identical features as an adult. The sex of hatchlings is determined by the incubation temperature of the eggs. Differences in size can be used to differentiate the sexes. Growth continues throughout their lifespan. The fastest rate of growth occurs during the first 2 years, then declines with age thereafter. For the first 5 years, P. palpebrosus grow at a rate of 6-8 cm per year. It takes approximately 10 years to for one of these caimans to complete maturity and develop full adult characteristics.

Reproduction

Courtship and copulation take place at the end of the dry season. At this time, the males, are seen to lift their heads high and hold their tails almost vertically out of the water. The males release what is described to be a “roar”-like sound. The description of the “roaring” varies, and it commonly heard as simply a grunt-like call. The varying sounds and noises indicate the actual complexity of mating rituals within this species. The male, which mates with multiple females, performs distinctive mating displays, then approaches any receptive female. Rather than during the day, P. palpebrosus prefer to mate during the night. Normally in shallow waters, copulation takes place with the female mounting the male and twisting her tail under his. The actual mating process can last anywhere between 5-10 minutes or even up to a whole day. It can also occur repeatedly over several days, after which both male and female settle in the water for a period. Most females are only able to breed once a year, but on the other hand, if bred in captivity and fed efficiently, the females are able to breed 2 or 3 times a year.

This species is reported to nest during the dry season, during the wet season, or all year round, depending on the locality. More specifically, studies show P. palpebrosus prefer to nest at the end of the dry season and the beginning of the rainy season in areas with warm climates. When ready to start nesting, the females stop feeding and begin the mating process. The females can lay around 10-25 eggs. Both female and male P. palpebrosus build nests for their eggs. These nests are made of soil, usually mud, blended with fresh and rotten leaves, small branches, and other vegetation. Like other caimans, this species is a mound-nester where the females lay their eggs and bury them underneath the mound. These nests are generally small in diameter and height. These eggs are white, long, and weigh anywhere from 61-70 grams. The eggs hatch after 90 days. The female opens the nest in response to vocalizations of the young from within the nests. After the young hatch from their eggs, they continue to stay beneath the debris of the nest for several days, staying away from the water. It is said that the adults open the nest and direct their young toward the water, but studies do show the lack of parental care. The general behavior of adult males are to leave once after the female lays her eggs. Males do not regularly stay near the females during the hatching or post-hatching period. Sexual maturity is dependent on size, and relates to age as it correlates with growth. When a male reaches a size of 1.1 meters, it has become sexually mature and the females are ready to breed when they are about 1 meter in length. For P. palpebrosus to become completely sexually mature, it could take more than 10 years.

The degree of parental care after hatching varies with local conditions. The nest is made by both parents. Studies show that the females remain with the hatchling group for only a few weeks before the hatchlings disperse. Then, the young are left alone and the mother leaves. The female rarely returns to her nesting site to search for her young, but can recognize them by smell. The nesting period is very dangerous for the young. Many predators lurk around nests to snatch eggs for food. In response, the female and male parents become defensive and take whatever action is necessary to guard their eggs. The female is always alert and remains near the nest during this period and will react to the slightest movement. Males do not regularly stay near the female during the hatching or post-hatching period. Furthermore, captive caimans are much more aggressive during their nesting period. The female can become very hostile and charge from the water at any sudden movement near the nest. She remains by the eggs for long periods, even without an apparent threat. Other defensive behaviors are tail slapping and splashing water by snapping their jaws. Sometimes, P. palpebrosus hatchlings are found alone or in pairs without any parental protection at all.

Lifespan/Longevity

The crocodilians are known to have long lifespans. Although P. palpebrosus adults are long lived, the exact longevity is not known. Generally, the adults have been known to live for 20-40 or more years. In captivity this species has a better longevity than of wild individuals.

Behavior

Paleosuchus palpebrosus is a social species with diverse and interesting behaviors. Like most crocodilians, they can convey social messages through sounds, postures, movements, smells, and touch. Although most crocodilians are somewhat social, P. palpebrosus are typically found alone or in pairs. When in pairs or small groups, P. palpebrosus are known to migrate long distances due to competition. Systematic studies of adults indicate that there are dominance hierarchies within groups. The most hostile and aggressive individuals appear to be the most dominant. These individuals control access to mates, nest sites, food, and living space. Dominance is asserted and maintained by social signals and displays. Challenges within a group may occur, but physical combat is rare. When threatened, this species may inflate its body to exaggerate size and begin to hiss defensively. Oftentimes, when an individual’s status is challenged, they will compete with each other by holding their bodies in a vertical position above the water’s surface, displaying their size to discourage their opponent from more aggression.

Home Range

Dominant males defend territories from which they exclude other males. The defended resources include access to mates, nesting sites, and foraging areas. Territories may be defended all year round and vary in size with seasonal changes.