Identification
Softshell turtles, in contrast to other turtle species, lack horny plates on
the shell, and are instead covered with a leathery skin. Most of the body is
scaleless, but modified scales do appear on the limbs. The carapace is broad
and flat, and for young turtles is olive to light yellowish brown or grey with
black spots, flecks and circles. While males retain their juvenile colors, females
tend to darken and become blotched with grey or brown. The only distinguishing
feature that separates the Western Spiny Softshell from the Eastern
Spiny Softshell, apart from geographic distribution, is that the dark spots
or markings on the carapace are greatly reduced in size, and may only be slightly
enlarged towards the middle of the shell. It is the short inconspicuous spines
at the front of the carapace that give these turtles their name. The limbs are
olive to light brown in coloration and may be marked with dark mottling, and
the feet are strongly streaked and spotted. The head of the spiny softshell
is long and narrow, with a yellow stripe boarded by black that extends from
the snout through the eye and onto the neck. The snout is long, with flexible
nostrils at the tip, each bearing a ridge.
Distribution and Status
The Western Spiny Softshell Turtle is found from central Minnesota, south through
the western states that border the Mississippi River to central Arkansas, and
west to northeastern New Mexico, eastern Colorado, and eastern Wyoming. Disjunct
populations are found in north eastern Wyoming and in much of central Montana.
In the Midwest, the Western Spiny Softshell is only found in Minnesota, Iowa,
and Missouri. (US
distribution map; Midwest
distribution map).
Ecology
Western Spiny Softshells are highly aquatic, and rarely leave the vicinity of
water. They prefer open habitats without aquatic vegetation and are commonly
found in larger streams, inland lakes, reservoirs, and other permanent bodies
of water. Because arid conditions are more prevalent in western states, rivers
offer much of the available suitable habitat. Being strong swimmers, these turtles
can withstand moderate currents and they use their elongated nose to breathe
at the surface of the water. Western Spiny Softshells often bury themselves
in the sand or hide under rocks at the bottom of their chosen body of water.
Much time is spent basking along banks or on logs in the water.
Threats and Management Issues
Declines in spiny softshell populations are attributed to pollution, exploitation
by humans, and the loss of suitable nesting sites. Nests are also readily destroyed
by raccoons, skunks, foxes and other mammals. Because of their soft shells,
hatchlings are extremely vulnerable to predation by raccoons, herons, and large
fish. The turtles are also sensitive to pollution, and have disappeared from
many polluted waterways across their range. Shoreline development also depletes
populations. Human interaction such as shooting turtles or harvesting them for
food, as well as injuries sustained from boat propellers, also effect the spiny
softshell.
Resources
Ernst. C. H., J. E. Lovich and R. W. Barbour. 1994. Turtles of the United States and Canada. Smithsonian Institution Press, USA.
General reference guides and websites.
Links to information on the Western Spiny Softshell Turtle outside the Herp Center
Bruce Kingsbury, Director
Center for Reptile and Amphibian Conservation and Management
Science Building
Indiana-Purdue University
2101 East Coliseum Blvd.
Fort Wayne, IN 46805-1499