Photo Credit: Jim Godwin
SCIENTIFIC NAME: Apalone calvata
STATUS: Common. Coastal plain portions of Mobile Bay drainage. MODERATE CONSERVATION CONCERN.
DESCRIPTION: The Gulf Coast smooth soft shell turtle (Apalone mutica calvata) is one of the two subspecies of smooth softshell turtles (Apalone mutica) in the Family Trionychidae. They are very similar to the other subspecies of midland smooth softshell turtles (Apalone mutica mutica), with the most notable differences being observed in the range of the two subspecies and the habitat in which they can be found. Gulf Coast smooth soft shell turtles are a medium to large freshwater turtle with an ovoid carapace that lacks spines on the front edge. Carapaces are covered by skin instead of the hard scutes generally associated with many turtle species. The species shows sexual dimorphism with females having a carapace length of 6.5 to 14 inches and males having a length of 4.5 to 10.5 inches. The coloration of the carapace is generally tan or brown in females and brown or gray in males. Both sexes have dark markings on the carapace, but the female’s markings may be in a blotchier pattern. The head, tail, and limbs are similar in color as the carapace. This species also has a tubular snout with round nostrils that lacks a septal ridge.
DISTRIBUTION: The Gulf Coast smooth soft shell turtle has a range that extends from the panhandle of Florida to Louisiana. Not a lot of information is available, but the turtle is known to inhabit the Pearl, Alabama, and Escambia River systems. Found in the western portion of the Coastal Plain.
HABITAT: Smooth softshell turtles are the most aquatic of all North American species of turtles. They can be found in creeks, rivers, and impoundments throughout its range. Unlike the very similar midland softshell turtle, the Gulf Coast soft shell turtle cannot be found inhabiting lakes, bogs, drainage ditches, or ponds which do not have adequate water flow. This species prefers an area with a sandy or muddy substrate and will avoid areas with a rocky substrate.
FEEDING HABITS: Although mostly carnivorous, smooth softshell turtles also consume some plant materials. They are an ambush predator using their long neck to grab passing prey while lying concealed in the substrate. They also are known to hunt out of water using the same technique and to use their nose to find food hidden in the substrate. Females generally will hunt in deeper waters, while the males will utilize the shallow waters near the shore.
LIFE HISTORY AND ECOLOGY: Gulf Coast smooth soft shell turtles spend the majority of their time in the water. Its morphological adaptations allow for it to stay submerged for extended periods of time often buried in the substrate. Smooth softshell turtles hibernate in the winter months by burying themselves in the substrate underwater. Breeding in this species is believed to occur in April to June. One to three clutches can be laid with up to 33 eggs. Clutches produced in the later times of the season usually contain fewer eggs. Nests are usually located on sand bars with little or no vegetation within 55 feet of the water’s edge. The female will usually burrow a tunnel and place herself at the opposite end of the nest. Eggs will hatch in 8 to 12 weeks after they are laid. The young are precocial once they have hatched. Males and females become sexually mature during their fourth and ninth year, respectively.
Smooth Softshell Turtle. Animal Diversity Web. University of Michigan Museum of Zoology.
Smooth Softshell Turtle. IUCN Red List of Threatened Species.
Smooth Softshell Turtle. ENature.com.
AUTHOR: Justin Brock, Wildlife Biologist, Alabama Division of Wildlife and Freshwater Fisheries