The smooth soft-shell turtle (Apalone mutica) is a species that is native to North America. As the name suggests, they have a softer shell than other turtles. The carapace (or shell) is made of leathery skin rather than the hard, armored scutes you find on other species.
Pancake-like, they are very flat turtles with distinctive facial features. These turtles have long necks and the head tapers into an elongated, tubular snout. They are olive-gray in color and blend in well with muddy bottoms.
There is also a spiny softshell turtle which is a different species.
The nose knows! These turtles are easy to recognize by their pointed snout and nostrils, their long necks, flattened body, and heavily webbed feet.
Species Variation and Region
There are two subspecies of smooth soft-shell turtles. The midland smooth softshell and the Gulf coast smooth softshell.
Midland Smooth Softshell
The midland smooth softshell, Apalone mutica mutica, lives in ponds, lakes, and rivers.
Gulf Coast Smooth Softshell
The Gulf Coast smooth softshell, Apalone mutica calvata only lives in rivers. They are mostly found from Louisiana to Florida.
Distribution of the smooth softshell turtles from Minnesota DNR.
Living Habitat
Smooth soft-shell turtles are particularly prone to drying out due to the nature of their shells. They are almost entirely aquatic, only venturing onto land to lay eggs and briefly bask in the sun.
They typically live in shallow medium to large rivers and streams with fast-flowing water. They are sensitive to pollution and prefer rivers with clean sand on the bottom. They prefer waterways that are not rocky or contain lots of vegetation.
The turtles spend a lot of their time buried in the sand or muddy bottoms with only their noses poking out above the water’s surface.
You can often spot them along sand bars, which they use for basking. The surrounding soft ground is important for them to lay their eggs in.
Range
The home range for males is approximately 0.3 miles and for females, it is approximately 0.8 miles.
Read my article on the Turtle Homing Instinct.
Diet
They are mostly carnivorous and feed on fish, insects, mollusks, and amphibians. They also scavenge for carrion and eat some vegetation.
Predation
Soft-shelled turtles have numerous predators, one reason they spend so much time submerged in the water. However, they are prey for snapping turtles and alligators in their water habitat.
The nesting time puts females in danger of being eaten by coyotes and foxes. The eggs are particularly vulnerable to raccoons and skunks who dig them out of the sand.
Humans also prey on them as a food source and for the illegal pet trade market.
Check out my video to see some cool turtles!
Brumation
Smooth soft-shell turtles brumate from November to March. They remain submerged and partially buried under sand and mud during hibernation. Fascinatingly, the turtles are able to survive during hibernation by absorbing oxygen through the skin that covers their shells.
They occasionally move in order to create currents of water that flow over their bodies. This replenishes the water that surrounds them with fresh, highly oxygenated water.
Read my article Night, Night, Sleep Tight: Hibernation, Brumation, and Torpor Explained.
Reproduction
Male smooth soft-shell turtles reach maturity at 4 years old and females 7- 9 years. As water temps warm the male travels around his territory seeking receptive females. Males may mate with numerous females.
They mate once a year between April and June. After 8 to 12 weeks, the females lay between 3 and 28 eggs in a single clutch. They bury the eggs in the ground at about 12 inches deep and not too far from the water.
The babies hatch 8-12 weeks later, weighing 0.19 ounces and measuring 1.6 inches long. Typically in August and September. They are independent as soon as they hatch and can find food for themselves.
Diseases and Zoonose
Like many reptiles, turtles can carry many different types of zoonotic bacteria. This means that bacteria, often excreted in the turtles' faces, can be passed on to people.
Handwashing before and after handling turtles is very important to prevent transmission of the bacteria.
This is most likely to happen when people keep reptiles as pets. Turtles, due to their relatively small size and the perceived ease of looking after them, are one of the most popular reptiles kept as pets.
Although humans can become very sick from these bacteria, turtles and other reptiles don't necessarily show any symptoms.
Salmonella is the most common bacteria found in turtles. Turtles can pick up the infection when they are being shipped for the pet trade. Also, the bacteria is found in the soil as well as contaminated feed and water which infect the turtle when ingested. Salmonella can also pass across the eggshell and infect the developing turtles inside.
Hunting and Trapping
Disturbance of waterways and nest sites with human traffic and boating can also impact turtle populations. Some are even caught as by-catch in some fishing nets.
In some US states, turtles are harvested commercially. In Missouri, snapping turtles, spiny soft shells, and smooth soft shells are legally harvested. Between 2002 and 2012, more than 216 million freshwater turtles were exported from the US.
There are few restrictions or regulations for turtle capture within the US and exporting these kinds of numbers is not sustainable.
Removing Turtles From Ponds
Smooth soft-shelled turtles feed mostly on other aquatic animals. They are sometimes considered a nuisance for pond owners and some people take special measures to deter them.
Regularly dredging your pond removes the substrate at the bottom that the turtles like hiding in. Some turtles can be physically removed.
If relocation is legal in your particular state, then the turtle can be relocated a few miles away. However, in the case of smooth soft-shelled turtles, they are most abundant in fast-flowing rivers and are less common in still water such as ponds and marshes.
Environmental Concerns
Currently, the smooth soft-shell turtle is considered as least concern on the IUCN Red List but it is becoming increasingly vulnerable due to human activity. Several states have it listed as a species of concern.
In Wisconsin, they are listed as Vulnerable. You can read more about Wisconsin Turtles here.
In neighboring Minnesota, they are considered a special concern species due to habitat loss, water pollution, and nesting habitat disturbance by human recreation.
Unlike their hard-shelled relatives, soft-shell turtles are more prone to pollution and poor water quality. This is because of their ability to exchange gases across their skin.
In some areas, the chemical rotenone is allowed to be placed in ponds to kill fish or may be used as an insecticide. Water contaminated with pesticides used to kill fish can inhibit turtles’ breathing.
How can we improve the habitat for smooth soft-shelled turtles?
Keeping the shorelines of any rivers or lakes natural is important for smooth soft-shelled turtles. They need soft surrounding substrate in order to bury their eggs. It could interfere with the turtles’ egg-laying if cycle paths and paved footways are placed alongside rivers or lakes.
Nesting turtles, their nests, and the eggs themselves can be disturbed by humans. Reducing boating activity near nest sites and preventing dog walkers from entering the area during nesting season can reduce the disturbance.
Soft-shelled turtles are extremely sensitive to water pollution. They depend upon highly oxygenated waterways for their survival. Pollution in rivers needs to be taken seriously and clean rivers need to be preserved. Water pollution also affects the prey populations, reducing the food availability for the turtles.
Although the smooth soft-shelled turtle is currently abundant across the United States, their population could begin to dimmish if we continue to destroy their habitat and overhunt them for the pet trade.
Author, Ame Vanorio, is the founder of Fox Run EEC, a teacher and environmental educator, and a licensed wildlife rehabilitator.
There are two species living in the United States, the common snapping turtle and the alligator snapping turtle. They live in freshwater habitats feeding on small animals.
Populations of the alligator snapping turtle are in decline and they are considered a vulnerable species. Habitat loss, climate change, and poaching are all reasons for this.