Dermatemys primarily inhabit the larger deeper rivers and oxbow lakes throughout the year. During the rainy season they will enter the flooded forests and travel up smaller river courses to nest. Often as flood waters recede they will become trapped in oxbow lakes until the next rainy season, since they are so poorly designed for terrestrial locomotion. Even though this turtle is a fast swimmer and is capable of swimming up rapids they often concentrate in the deep pools at the bottom of the river during the day (Vogt unpublished data). Well oxygenated water is preferred, as they have highly vascularized papillae in the larynx which enable them to stay underwater indefinitely, drawing water in through the mouth and exhaling through the nostrils. However anaerobic black water oxbow lakes used to hold large concentrations of Dermatemys that are trapped there after the water level of the river recedes in the dry season. Although Dermatemys will use fast-moving sections of rivers, they often seek respite from the current in the calmer parts of deep pools and are found in association with submerged tree trunks imbedded in the river bottom. Larger turtles usually rest on the bottom and sometimes partially imbed themselves if the substrate is soft enough. Small individuals often seek shelter closer to shore, resting partially imbedded in accumulations of detritus and also hidden amongst the branches of submerged trees. During April and May, the dry season, adult Dermatemys congregate in the deeper waterholes, 6 m or more in depth. During this same time of the year juveniles and subadults can be found along the shorelines of smaller tributaries taking refuge within the branches of fallen trees or mounds of accumulated detritus (Alvarez del Toro et al. 1979, Polisar 1996, Vogt pers. obs.). Populations in Belize are known to enter estuaries (Moll 1989). Dermatemys is an herbivorous turtle throughout its life (Alvarez del Toro et al. 1979, Moll 1989, Vogt unpublished data). It eats a wide variety of aquatic vegetation, fallen leaves and leaf detritus, and fallen fruits from riparian vegetation. Belizean populations are also known to enter estuaries to feed upon mangrove vegetation and sea grasses (Moll 1989).

Females reach maturity between 34.2–42.0 cm, while males become mature between 32.8-38.5 cm (Polisar 1996, Vogt unpublished data). Females grow larger than males; largest size reported is 60 cm and 22 kg (Alvarez del Toro et al. 1979), although none of 567 turtles examined by Polisar (1996) in North-Central Belize during 1989–1990 exceeded 49 cm. No information is available on age at maturity or on longevity.

Nesting begins during the height of the rainy season from September through December when water levels are at their annual peaks; up to three, exceptionally four, clutches of eggs are laid (Vogt and Flores-Vilela 1992, Polisar 1996). Reports in the literature describing the nesting season as March and April (Lee 1969, Moll 1986a) were based on turtles found in the markets that were most likely holding their eggs for an extended period due to their captive condition. Some females may lay their ultimate clutch for the season in late February or early March, but these are anomalies. Vitellogenesis begins in June and July with oviposition from September to March in the Rio Lacantun in Chiapas (Vogt unpublished data).

Nests are excavated within 3 m of the shoreline, usually within 1 m (Alvarez del Toro et al. 1979), often in saturated soil. Nests are often constructed under an overhanging river bank. Since the nests are scattered along a dynamic shoreline during the rainy season they often go undetected by predators. Often nests are exposed by flood waters creating the misconception that this species of turtle lays its eggs underwater (Vogt unpublished data). The earliest nests of the season are often inundated for weeks at a time with no effect on survivorship. Polisar (1992) documented 80–100% hatching success in eggs subjected to more than 30 days of submersion in water. The physiological mechanisms of this emybryonic diapause need to be investigated further.

Up to three clutches were laid per year in Chiapas, with clutch size ranging from 6-16 eggs. Incubation time in the laboratory varied from 115–223 days, this variation is attributed to embryonic dormancy. Diapause allows the eggs to remain at an early developmental stage when environmental conditions are not favorable for development, cool temperatures and flood conditions, diapause is broken by drying of the nests and warmer temperatures. Clutches laid over a 4 month time span hatch synchronously, stimulated by moistening of the soil during the first summer rains (Vogt unpublished data). In Belize Polisar (1992) reported 217–300 days between oviposition and hatchling emergence. Vogt and Flores-Villela (1992) reported that incubation temperatures in the laboratory above 28° C produced all females and temperatures of 25–26° C produced males.

Inhabits the regions within the large rivers from the Papaloapan basin in central Veracruz and along the lowlands of the Usumacinta basin in the States of Tabasco and Chiapas, as well as in Campeche, Mexico, through Belize and the large rivers and lakes of the department of Peten on the Atlantic coast of Guatemala. There are no records for this species in either the State of Yucatan or in the northern part of Quintana Roo (Iverson and Mittermeier 1980, Iverson 1992, Campbell 1998, Vogt unpublished data). (See Figure 1 in the supplementary material for a map of the extent of occurrence).

Dermatemys has been subject to legal protection in Mexico since 1927, as under the Mexican Constitution all natural resources belong to the Nation and can only be exploited with formal authorization/permits. Dermatemys was included in the Mexican Red data list (NOM-059-ECOL 1994) as endangered, making all forms of harvest and exploitation illegal. However, very little is done to enforce the law and few people respect it (Vogt pers. obs.).

In Belize, there is national legislation (Statutory Instrument No. 55, of April 1993) designed to control the level of harvest and establish some protected populations (Polisar 1994). The efficacy of this legislation needs to be evaluated and the nation-wide status of the species assessed.

Dermatemys is protected under Guatamalan law (Campbell 1998) but exact details are not available.

D. mawii is categorized as a highly protected species under the U.S. Endangered Species Act (Code of Federal Regulations, 1987).

Dermatemys is listed on Appendix II of CITES.

Laguna La Popotera, Veracruz, Mexico, was designated a RAMSAR site in 2005 with specific hopes of creating the first extensively managed wildlife reserve specifically for Dermatemys (Horne in litt. to TFTSG RLA, 27Jul 05). The species is present in Laguna del Tigre N.P. in Peten, Guatemala, and was recommended as a focal species for park management (Castañeda Moya et al. 2000).

Currently there are several ex situ populations of this species with which viable breeding colonies can be established in different zoos and farms. Some of these ex situ populations are: Nacajuca, Tabasco, with 880 turtles, La Florida, Veracruz, with 45 turtles, the Veracruz Aquarium with 2 animals, Chicago Zoo with 2 animals, Detroit Zoo with 2 animals, Philadelphia Zoo with 9 specimens, and the Guatemala City Zoo with one animal.

In 2004 a group for D. mawii conservation was established, proposing a program that includes raising the authorities' and people’s awareness on the species, its captive conservation that includes the genetic management of the captive populations, evaluating the wild populations and their habitat, improved enforcement of existing legal protection, promotion of harvest management measures for sustainable use, and the creation of a reintroduction program.

In summary, existing protective measures need to be implemented, populations inhabiting protected areas must be watched over carefully, and careful thought must be given to meeting some, if not all, of the intensive commercial demand for the species by sustainable production from farms.