Spotted Turtle (Clemmys guttata)

CLASSIFICATION

The Spotted turtle (Clemmys guttata) belongs to the family Emydidae, which is the largest and most widely distributed of the turtle families. The Spotted turtle is one of five species from this family that can be found in Ontario.

DESCRIPTION

The Spotted turtle is a small, freshwater turtle which rarely exceeds 127mm in length. Its carapace is smooth, low, oval, keeless and without serrations on its posterior margin. The shell is black or blue-black in colour, and is decorated with between three and ninety-two small yellow-orange spots. The spots are transparent windows in the laminae, overlying patches of yellow pigment, and they vary with age, sex, and geographical location. The large, unhinged plastron is yellow or cream in colour, with a black blotch in each scute. In older individuals the plastron may appear predominantly black. The skin on the upper side of the head, neck, and limbs of Spotted turtles is dark grey or black, with a varying number of yellow spots. The ventral surface of the limbs is reddish to yellowish in colour. The head is decorated with a broken yellow band near the tympanum and in some individuals another band extends back from the orbit. Sexual dimorphism is apparent, with males having tan chins, brown eyes, and slightly concave plastrons, while females have yellow chins, orange eyes, and flat plastrons.

Distinguishing features: The yellow spots on the black shell are the most easily recognizable distinguishing features of the Spotted turtle, but the yellow spots on the head and neck, the yellow bar behind the ear, and the extensive black area on the plastron are all diagnostic features as well.

RANGE

The Spotted turtle is primarily found in northeastern North America, east of the Blue Ridge mountains. Its range extends from southern Maine southward through the eastern seaboard states to north central Florida. There are also relatively isolated populations in central Indiana and the western Carolinas. At the northern limit of its of range the Spotted turtle also occurs in eastern and southwestern Ontario, and in parts of Quebec. There are isolated records for the Spotted turtle in all counties in the Kawartha Lakes region except Northumberland, but overall this species appeared to be present in very low numbers.

HABITAT

Spotted turtles can be found in relatively unpolluted, small, shallow bodies of water such as marshes, ponds, ditches, meandering creeks, bogs, flooded pastures, forested woodlands, and brackish tidal pools. Spotted turtles are often associated with wooded areas, and they require a soft substrate and at least some aquatic vegetation in their aquatic habitats.
 
 

HABITS

Spotted turtles over-winter in communal hibernacula containing up to twenty-three individuals. These are often located on the muddy bottoms of fairly shallow waterways (55-95cm), which are characterized by a slow, steady flow of water. Seasonal activity typically begins around the time of spring thaw. The earliest recorded date of observation for Spotted turtles in the Kawartha Lakes region occurred on April 11 (1995), although there have been sightings of this species moving around beneath the ice during the winter months as well. During the period from March to May Spotted turtles typically inhabit wet areas in fields or wooded marshes but move into more vegetated areas during the period from May to July. During the hot summer months (August to October) Spotted turtles often aestivate in soft substrates or muskrat burrows. Spotted turtles are most often seen during the spring when they come out to bask in groups on logs, stumps, grass mats, and tussocks. In the Kawarthas only 6.7% of the records for this species described basking individuals, indicating that relative to other turtle species in this area they do not spend a lot of time engaged in this activity. Spotted turtles often migrate hundreds of meters between their aquatic habitats and their terrestrial nesting grounds, and over land movement by solitary individuals is fairly common. In the Kawartha Lakes region the largest number of recorded observations for this species occurred in April, with a slow decline in frequency toward the summer months. In late October or early November they typically return to flooded puddles and ponds where they over winter under the ice until late February or early March. The latest recorded observation of a Spotted turtle in the Kawartha Lakes region occurred on October 20 (1991).

The Spotted turtle is a fairly gentle species, although it may try to bite when captured. If disturbed in the wild it will dive into the water and hide in the mud or aquatic vegetation.

REPRODUCTION

Mating

Sexual maturity occurs between seven and ten years of age, or a carapace length of approximately 80mm. Courtship behaviour has been observed between March and July in Ontario populations, and typically involves a ritual in which the male chases the female, often nipping her legs and shell margins. The chase can cover a distance of between 30-50m and can last between 15-30 minutes. Multiple males may also fight with each other for the right to court a single female. Copulation can occur on land, but most often occurs in shallow water adjacent to land.

Nesting

Nesting sites usually consist of sunny, elevated patches that can range from areas with well drained soils, sandy sod, and grassy tussocks to sand dunes. Nesting usually occurs in June, and most of the activity takes place during the morning hours. Females use both hind feet in an alternating pattern to dig their shallow, flask shapes nests, which are completed at a depth equal to the reach of each foot. The whole process has been reported to take between 45 and 120 minutes. Clutch size is relatively small, usually consisting of between 3-8 white, soft-shelled, elliptical eggs. Estimations of the incubation period required for Spotted turtles is variable, but usually between 60-83 days, depending on the temperature and humidity. This means that hatchlings usually emerge in mid-late August or early September. The almost circular young are usually around 28mm at hatching, and typically have a smooth shell with a weak keel and are decorated with one yellow spot per scute.

FEEDING

Spotted turtles are primarily carnivorous, but plant material is occasionally consumed as well. Their main dietary components include insects, worms, slugs, snails, crayfish, spiders, millipedes, frogs, tadpoles, and fish carrion. Most foraging and consumption of food takes place under water.

THREATS

Among the primary threats to the long term survival of Spotted turtles are the loss, fragmentation, and modification of habitat, including the drainage of wetlands, deepening of marsh habitats in favor of waterfowl populations, and development of shoreline areas. In addition, road related mortality is thought to be a significant factor for Spotted turtles as they travel over land to nest. There are no records for Spotted turtles killed on roads or highways in the Kawartha Lakes region, but this likely due to the extremely small number of records for this species. In Ontario pollution of aquatic habitats by substances such as DDT and PCB’s is also thought to be a problem for some Spotted turtle populations. Historically, Spotted turtles were also collected for the pet trade. The main predators of Spotted turtles include raccoons, dogs, snapping turtles, skunks, foxes, and other small mammals.

CONSERVATION STATUS

SRANK: S3 COSEWIC: Special Concern MNR: Vulnerable

The Spotted turtle has been designated as S3 by the Natural Heritage Information Center, indicating that it is rare or uncommon in Ontario, with only 20-100 records. In addition, it has been designated as a species of special concern by COSEWIC and as Vulnerable by the MNR, indicating that it is particularly susceptible to human activities and stochastic environmental activities. As such, management and conservation strategies should be aimed at protecting primary terrestrial and aquatic habitats from development, disturbance, and additional pollution.
 

REFERENCES

Carr, A. 1952. Handbook of turtles: the turtles of the United States, Canada, and Baja

California. Comstock Publishing Associates, Ithaca and London.

Chippindale, P. 1987. Coutship and nesting records for Spotted turtles (Clemmys

guttata) in the Mer Bleue bog. Canadian Field Naturalist 103: 289-291.

Ernst, C.H., and R.W. Barbour. 1972. Turtles of the United States. The University of

Kentucky Press, Lexington County, Kentucky.

MacCulloch, R.D. 2002. The ROM field guide to amphibians and reptiles of Ontario.

McClelland and Stewart Ltd., Toronto.

Mitchell, J.C. 1994. The Reptiles of Virginia. Smithsonian Institution Press, Washington

and London.