Softshells include some of the world's largest freshwater turtles, though many can adapt to living in highly brackish waters.

Females can grow up to several feet in carapace diameter, while males stay much smaller; this is their main form of sexual dimorphism.

Most are strict carnivores, with diets consisting mainly of fish, aquatic crustaceans, snails, amphibians,[4] and sometimes birds and small mammals.

Softshells are able to "breathe" underwater with rhythmic movements of their mouth cavity, which contains numerous processes copiously supplied with blood, acting similarly to gill filaments in fish.

Moreover, the Chinese softshell turtle has been shown to excrete urea while "breathing" underwater; this is an efficient solution when the animal does not have access to fresh water, e.g., in brackish-water environments.

[7] According to Ditmars (1910): "The mandibles of many species form the outer border of powerful crushing processes—the alveolar surfaces of the jaws", which aids the ingestion of tough prey such as molluscs.

According to a 1930 report by Soame Jenyns, Guangdong restaurants had them imported from Guangxi in large numbers; "eaten stewed with almonds, roast with chili sauce or fried with bamboo shoots, they [were] considered a great delicacy.

[17] Family Trionychidae The following cladogram shows the relationships among the species:[19] Cyclanorbis Cycloderma Lissemys Hutchemys Plastomenus Trionyx Chitra Pelochelys Apalone Rafetus Amyda Aspideretes Nilssonia Dogania Palea Pelodiscus