As with many turtle species, the growth rate of the Brazilian snake-necked turtle is low, with recorded individuals gaining only around 100 grams in weight and 7 millimetres in size over 10 years of monitoring. The average life expectancy of the Brazilian snake-necked turtle is 100 years (5). Despite this slow growth, the population density of the Brazilian snake-necked turtle can reach extremely high levels, with in excess of 190 individuals per river hectare being recorded in some parts of its range (2).
Reproduction in wild populations of the Brazilian snake-necked turtle is not fully understood but it is thought that the breeding season lasts from September to January. Observations of increased activity at this time suggest that breeding may correspond with the rainy season. It is thought that the female Brazilian snake-necked turtle lays clutches of 1 to 3 eggs beneath leaf litter or between tree roots, with an incubation period of around 250 to 300 days (2).
The diet of the Brazilian snake-necked turtle varies with seasonal prey abundance; however, it feeds primarily on aquatic invertebrates such as insect larvae and small crustaceans in areas of relatively still water. It may also prey on terrestrial species that fall into streams, such as earthworms, termites, crickets and spiders, or even small frogs (3).
The Brazilian snake-necked turtle’s long neck allows it to stay in deep water to avoid predation. After being submerged for about 15 minutes, the Brazilian snake-necked turtle can extend its neck to reach the water’s surface with its nostrils, enabling it to breathe without having to reveal its whole body to predators. The long neck is also used to lever the turtle back upright if it should fall over onto its back when on land (3).