The eastern spiny softshell (Apalone spinifera) is a medium to large turtle and easily distinguished from other turtles found in Vermont by their very pointed snout and leathery shell. This turtle was named spiny softshell because the front edge of the carapace (upper shell) behind the turtle’s head is studded with knobby projections called tubercles. The carapace is flattened and covered with leathery skin instead of bony plates. Small sharp projections roughen the carapace surface, making it feel like sandpaper.
Spiny shoftshells may live more than 50 years. Females are much larger than males, reaching a shell length of up to 21 inches and weighing as much as 25 pounds. Males reach a maximum carapace length of about eight inches.
Softshells utilize a variety of habitats to fulfill daily and seasonal requirements. Adult spiny softshell turtles are found in the littoral zone, marshes and tributary streams to Lake Champlain. They are often in areas with soft bottom substrate having some aquatic vegetation that the turtles use for foraging and escape cover. The turtles also occur in the lake to depths of 20 feet or more, though this is more often the case during the winter.
Softshells come out of the water in sheltered places and bask in the sun for hours at a time. They will bask on fallen trees with underwater limbs, sandbars and mudflats. Individual and group basking also occurs on rocks, logs, mud flats, sand banks, and floating debris.
Softshells in Lake Champlain hibernate for almost six months, generally from November through April. They tend to use the same overwintering sites every year. These sites are called hibernacula. Hibernacula provide well oxygenated water, are free of ice scour, and lack disturbance that would cause a turtle to leave the site.
Nesting and incubation occurs in the well-drained sand and gravel shores of Lake Champlain and tributary streams. The areas are relatively free of vegetation and exposed to the sun for a large portion of the day to ensure successful egg incubation.
Female spiny softshells are sexually mature at about twelve years old. Their shell length will be seven to eight inches. Males shell length at sexual maturity will be about half that size. Softshell turtles in Vermont and Quebec may take longer to mature because their growth may be slower at our northern location.
Mating typically takes place in May. Cool spring temperatures or high water levels that temporarily submerge nesting substrate can result in delayed nesting. Females dig nests in open areas along the shore of the lake or river in June. A female will lay about 20 eggs, which she buries in the sand or gravel. Good sun exposure is a must, because soil temperature determines how long the eggs take to develop and hatch.
Incubation typically lasts 82-84 days with hatchlings emerging from late August into October. Unlike some other turtle species, spiny softshell turtle hatchlings cannot survive tissue freezing and must emerge from their natal nests in autumn to hibernate under water.
Spiny softshell turtles actively seek food by probing along the bottom, beneath objects, or in clumps of submerged vegetation. They may also conceal themselves on the bottom in mud or sand and ambush passing prey animals with quick thrusts of their long necks. Spiny softshell feed on crayfish, aquatic insects, mollusks, earthworms, tadpoles, frogs, minnows and other organisms.
Threatened in Vermont
In 1987, the spiny softshell was state-listed as threatened in Vermont. In 1991, it was nationally listed as threatened in Canada and officially listed as threatened in Quebec in 1999. More recently it has been designated a Species of Greatest Conservation Need (high priority) in Vermont’s Wildlife Action Plan.
Softshell turtles currently persist in Lake Champlain as a small subpopulation in the Lamoille River area of Vermont and as a somewhat larger subpopulation at the northern end of the lake in both Vermont and Quebec. It is believed that the population numbers less than 300 adults and large juveniles. No population has ever been documented on the New York side of Lake Champlain and no other populations are currently known to exist in New England or Quebec.
Several factors threaten spiny softshell turtles including:
- Direct loss of nesting, basking and winter hibernation sites through changes to shoreline and development.
- Dams on rivers. They alter the shape of the river, act as barriers to movement and migration, and change water flow and levels. Changing water levels can cause nest flooding and egg mortality.
- People disturbing the turtles when they are nesting or basking, causing this shy species to abandon their activity and retreat to the safety of water.
- Aquatic activities, such as boating and fishing, during the nesting period may delay or discourage nesting or physically damage animals. Anglers may mistakenly hook turtles while fishing. Boat traffic causes a risk of boat propellers injuring turtles.
- Raccoons and skunks love turtle eggs and hatchlings and these predators tend to find them easily. Waste food left behind by picnickers in areas where turtles nest can attract predators and increase the risk of predation. Uncontrolled dogs can also be a threat to softshell turtles.
Several large, communal nesting beaches are intensively managed for the spiny softshell, with map, snapping, painted, and musk turtles also benefiting. Initial monitoring not only enhanced knowledge of distribution but also made it clear how to manage communal nesting areas to save eggs and hatchlings from predation, parasitic flies, and drowning. A combination of electric fencing and trapping along with rope lines and signs are used to deter predation and human disturbance.
Covering large sections of nesting substrate post-nesting with wire mesh has proven to be an important predator deterrence method. ECHO Lake Aquarium and Science Center partners with the department for captive care during the winter. Many young and eggs are rescued each year from partially emerged nests.
- Download eastern spiny softshell turtle recovery plan
- View videos of softshell turtle Head Start Program
- Review spiny softshell project summary
What You Can Do
- Do not disturb turtles on their nesting and basking sites. Stay at least 300 feet away and honor warning signs when posted. Use binoculars to get a great view.
- Boaters and anglers should maintain a respectful distance from nesting and basking sites to avoid accidental hooking or injury from boat propellers.
- Remove garbage from beaches to avoid attracting skunks and raccoons to nesting sites throughout the summer.
- Keep livestock and house pets away from nesting sites during the summer.
- Learn how to properly release a hooked turtle to reduce stress and injury to both parties. If you hook a turtle while fishing or when it is on land, put it back in the water and contact Fish & Wildlife at 802-828-1000.
- Get involved. Observe and report turtle sightings and nesting activities in your area.
- Support spiny softshell conservation programs. Purchase a Conservation License Plate or donate to the Nongame Wildlife Fund.