Paleosuchus palpebrosus

Common names: Dwarf caiman, Cuvier’s smooth-fronted caiman, Jacaré pagua, Cachirre, musky caiman, Cocodrilo Range: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Paraguay, Peru, Surinam, Venezuela Revised by Robert Godshalk

CITES: Appendix II
CSG Action Plan: Availability of Survey Data – Poor
Need for Wild Population Recovery – Low
Potential for Sustainable Management – Low
1996 IUCN Red List: Not Listed (LRlc Lower Risk, least concern. Widespread and remains locally abundant although quantitative data on trends is lacking.)
Principal threats: Habitat destruction, local subsistence hunting.

Ecology and natural history

The two species of Paleosuchus are very similar to each other and can be confused. They are both small, secretive and are frequently sympatric. Until recently, very little work has been done on either species. Ecological work on this genus was done by Federico Medem (Medem 1981, 1983). This dwarf caiman is essentially restricted to the Amazon and Orinoco River drainages and the Atlantic coast drainages that lie between these two rivers. Limited populations inhabit the upper Paraguay River drainage in Paraguay (Medem 1983, Scott et al. 1990). Much of what is known concerning the ecology of the dwarf caiman is summarized in Magnusson (1989) and Ouboter (1996). Ecological studies are currently being undertaken in Brazil (Campos et al. 1995).

The dwarf caiman inhabits a number of aquatic habitats in the central Amazon basin, including the flooded forests near the major rivers and lakes (Magnusson 1985). On the Brazilian shield (Rebelo and Louzada 1984), and in the Venezuelan llanos, the species occurs in streams lined by gallery forest (Thorbjarnarson 1992). It does not inhabit small forest streams that drain rainforest tracts, a principal habitat for P. trigonatus (Magnusson 1992a). Ouboter (1996) considers it a species of the shallow margins of blackwater rivers in Suriname.

The water is frequently nutrient poor, and may be acidic, as in the Mauritia palm swamps in Venezuela (Godshalk 1982a). Terrestrial movement may be extensive in order to reach ephemeral wetlands (Paolilla and Gorzula 1985). King and Videz-Roca (1989) report both species of Paleosuchus present in both large rivers and small streams in Bolivia, usually along stretches of bare shore and frequently in association with dead trees.

The dwarf caiman may be the smallest extant species of crocodilian in the world, with the maximum length of males reported to be only about 1.6m (Medem 1981). Ouboter (1996) reports animals of 1.8m in Surinam. Little is known about its reproduction, but females are known to make mound nests during the rainy season and lay 10–15 eggs.

Conservation and status

Both species of Paleosuchus have well-developed osteoderms over most of the body. This, and the species small size, makes the hide virtually worthless commercially and has resulted in only limited hunting pressure. Basic surveys have been conducted in a large majority (80%) of the countries containing this species. Most surveys were undertaken to determine the status of other crocodilians, but reported on Paleosuchus as well. Hines and Wilkinson (pers. comm.) report night count densities of 0.83 – 2.20/km on the Rio Curaray in Ecuador. Subsistence hunting does take place widely, and can locally reduce Paleosuchus densities, but populations of this species do not appear to have been impacted much. However, gold mining activities and its resultant pollution are increasing and also have an impact on this species in certain areas.

The dwarf caiman holds little potential for the development of commercially oriented management programs. The primary value in most countries is for subsistence hunting by rural inhabitants. Paleosuchus is sometimes taken preferentially over Caiman spp. Commercial exploitation in Guyana is based on the capture and sale of dwarf caiman for the pet industry.

Priority projects

Moderate priority

Investigations of ecology and population biology: This species is perhaps the least known of the New World crocodilians. Even such basic topics as prey, habitat preference and reproduction are poorly known. Ecological interactions with other crocodilians and the effects of subsistence hunting would be important management topics to address. Areas where ecological investigations could be fruitfully undertaken include the Brazilian Amazon, Guyana, and the Venezuelan Guyana region. Bolivian populations have long been isolated from disturbance and would also be suitable.

Dwarf caiman, Paleosuchus palpebrosus, (below) and smooth-fronted caiman, Paleosuchus
trigonatus, (above) in Guyana. These two similar small species remain widely distributed
in South America. Photo by P. C. H. Pritchard.