The spiny softshell is Ontario’s only turtle with a flexible, leathery carapace (upper shell) and the only species in the province that can attain a size comparable to that of the snapping turtle.
Ontario’s most peculiar looking turtle, the spiny softshell has a long snout and a leathery carapace with small spiny projections at the front edge. The carapace is olive-grey, brownish or tan, and its edges are yellow with a black outline. The carapace of males and juveniles has large spots with a dark outline, whereas the spots on the carapace of females are smaller and are not outlined. The legs and head are dark green or grey with dark patterning, and along each side of the head is a distinct yellow stripe outlined in black. The carapace of females of this large turtle may reach 43 centimetres in length, and that of males may reach a length of about 23 centimetres.
Other names: eastern spiny softshell turtle, Trionyx spiniferus, Trionyx spiniferus spiniferus, Trionyx ferox spinifera, Amyda ferox spinifera
With its soft, leathery carapace and pointy snout, the spiny softshell is unlike any other turtle in Ontario.
Spiny softshells are generally found in rivers with soft bottoms, aquatic vegetation and sandbars or mudflats but also occasionally in lakes or impoundments. These turtles require gravelly or sandy areas for nesting and deep water for hibernating. They are primarily aquatic and are never far from water, in which they hide from prey and predators. Softshells regularly bask along the riverbanks or on rocks.
In Canada, females of this species may take more than 10 years to mature. Spiny softshells mate in spring, usually in deep water, and nest in June and July in open sandy or gravelly areas close to water. Females lay up to 36 eggs, though the typical clutch size is around 20. Unlike in most turtle species, in the spiny softshell the gender of the hatchlings is independent of incubation temperature. Eggs hatch in late summer or fall. The young are three to four centimetres long and may not emerge from the nest until the following spring.
Spiny softshells feed primarily on insects and crayfish but may also eat molluscs, fish, amphibians, carrion and vegetation. These turtles can get almost half the oxygen they require by breathing through their skin while in water, which allows them to stay under water for up to five hours. Individuals may move up to 30 kilometres over the course of a summer, and daily movements exceeding four kilometres have been observed. Spiny softshells can live for over 25 years in captivity but up to about 50 years in the wild.
Threats and Trends
Much of the historic habitat of the spiny softshell has been lost, and the degradation and fragmentation of what little habitat remains, primarily as a result of shoreline development, threatens the persistence of this species in Ontario.
The causes of recently observed poor nesting success are the subject of ongoing studies and may include environmental contaminants, sacrophagid fly infestations and the disturbance of nesting sites by both humans and predators. Injury and death due to boat propellers and fishing also threaten this species.
Current Status and Protection
The spiny softshell turtle is currently listed as Endangered by the Committee on the Status of Endangered Wildlife in Canada and Endangered under the federal Species at Risk Act and is Threatened under the Ontario Endangered Species Act, 2007. The species has also been designated as a Specially Protected Reptile under the Ontario Fish and Wildlife Conservation Act. These acts offer protection to individuals and their habitat. The habitat of this species is further protected in Ontario by the Provincial Policy Statement under the Planning Act. The International Union for Conservation of Nature has not assessed the global status of the spiny softshell. The species’ status was confirmed in January 2010. Additional detail about legal protection for species at risk in Ontario is available on our Legal Protection page.
Learn more about reptile and amphibian conservation and what you can do to help these species on our Reptile and Amphibian Stewardship page.