Spiny Softshell

IUCN Red List

LC - Least Concern

NatureServe

N5 - Secure
S5 - Secure

Minnesota

not listed
Threatened
Special Concern
Species in Greatest Conservation Need

There are just three species of softshell turtle native to North America. Two occur in Minnesota. Of these, Spiny Softshell is by far the most common. It occurs in the United States from Vermont to Florida west to Minnesota, Colorado, and California; in southern Ontario Canada; and in Mexico. It is found mostly in rivers but also in streams, lakes, and ponds. It prefers open areas with sandy or muddy bottoms and a small amount of vegetation. There are seven subspecies of Spiny Softshell. Only one, northern (eastern) Spiny Softshell (Apalone spinifera spinifera), occurs in Minnesota.

Spiny Softshell is a large freshwater turtle. Size is usually given given as the length of the upper shell (carapace). Males are 5″ to 9½″ (12.7 to 24 cm) long. Females are much larger, 9½″ to 19″ (24 to 48 cm) long. The carapace is rounded, smooth, leathery, and flexible on the edges. There are no scales (scutes). There are many small spines but these are restricted to the front edge near the neck. This is the feature that gives the turtle its common name. The background color is light brown to olive green and there is a thin dark line near the margin. On the male and on juveniles of both sexes there are numerous dark circles. As the female ages the carapace darkens and the circles become blotches.

The lower shell (plastron) is whitish or yellow.

The upper side of the head, neck, and limbs are are colored similar to the carapace. The chin is yellow. On the neck there are two yellow lines, an upper and a lower, bordered by black. The lines do not connect. The upper line continues through the eye. The nose is elongated, snout-like, and turned up at the end. Males have longer, thicker tails. On the female the tail barely extends beyond the carapace.

The feet are webbed and clawed.

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The description above refers to the Northern (Eastern) Spiny Softshell (Apalone spinifera spinifera).

Size

Male carapace length: 5″ to 9½″ (12.7 to 24 cm)

Female carapace length: 9½″ to 19″ (24 to 48 cm)

Similar Species

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Rivers, streams, lakes, and ponds, in open areas with sandy or muddy bottoms and a small amount of vegetation.

Behavior

Spiny Softshell is active during the day, often basking on logs and riverbanks. It can both breath air and can take oxygen from the water, allowing it to spend a long time underwater. It is a fast swimmer, faster than the fish that it preys upon. When handled it can extend its long neck and deliver a painful bite. From October to April it is dormant and buried in the substrate.

Lifespan

A large female can live up to fifty years.

Life Cycle

The female lays up to 40 eggs in a nest once or twice a year. After laying the eggs she has no further involvement with the eggs or with the young.

Food

Aquatic invertebrates including crayfish, snails, aquatic insects, frogs, and fish.