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Spiny Softshell

Apalone spinifera

Family: Trionychidae

The sub-species of Spiny Softshell that occurs in Canada is the Eastern Spiny Softshell (Apalone spinifera spinifera).

COSEWIC status:
  • Endangered
SARA status:
  • Threatened
IUCN status:
  • Least Concern

Description

The Spiny Softshell has a long snout and a leathery carapace (upper shell) 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 adult 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. Females can attain a maximum carapace length of 43 cm, while males rarely exceed 23 cm carapace length. Hatchlings have a carapace length of 3–4.4 cm and resemble the adults.

Similar Species

With its leathery carapace and unusually long snout, the Spiny Softshell is unlike any other freshwater turtle in Canada.

Distribution

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The Canadian range of the Spiny Softshell is limited to southwestern Ontario and a few locations in extreme southwestern Quebec. In the United States, the range of this species extends throughout the Mississippi basin and as far south as Texas and into Mexico. It has also been introduced beyond its native range into the western United States and Hawaii.

Habitat

Spiny Softshell turtles are generally found in large rivers or lakes with soft bottoms, aquatic vegetation and sandbars or sandy shorelines. Females nest along gravel or sandy shorelines, typically within a few metres of the water’s edge. Spiny Softshell turtles overwinter underwater in deeper areas.

Biology

In Canada, Spiny Softshell turtles are dormant during the winter and are typically active from April until early October. Individuals mate in the spring and females lay 6–36 oval eggs in June and early July. The eggs hatch in late August or September. Unlike most Canadian turtle species, the sex of Spiny Softshell hatchlings is determined genetically, independent of incubation temperature. In Canada, females of this species mature around 12 years of age and individuals can live for more than 50 years. Spiny Softshells feed on insects, crayfish, molluscs, fish, amphibians, carrion and vegetation. Home ranges can be up to 30 km in length, and daily movements exceeding 4 km have been observed. Spiny Softshells are primarily aquatic and bask along riverbanks or by floating just below the surface of the water, often with their long snout protruding from the water like a snorkel.

Threats

Habitat loss and degradation, primarily as a result of shoreline development and the operation of dams, threatens the persistence of this species in Canada. Illegal collection for consumption continues to be a serious threat, and several incidents of illegal poaching have been documented in Canada in recent years. Injury and death due to boat propellers and fishing likely contribute to unsustainable rates of adult mortality in some areas, while nest predation by subsidized predators (e.g. Raccoon, Skunk) results in high nest mortality throughout most of this specie’ Canadian range. Climate change may also pose a serious future threat to Canadian turtles. This species continues to decline throughout its small Canadian range, with the exception of one site that is undergoing significant management.

Additional Information About This Species In Canada