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This site was created by students in the herpetology class at Towson University.  Site last updated: 05/21/07.

Acknowledgements: Herb Harris - Range Maps;  Mark Tegges - Photography; Dan Lapascha & Gigi Forester - TU Herpetology Logo

Eastern mud turtle

(Kinosternon subrubrum)

Description

    The Mud Turtle is a relatively small turtle with a domed carapace ranging in length from 7.1 – 12.4 cm.  The carapace is smooth, patternless and olive to dark brown colored with no enlarged marginal scutes.  The plastron is double-hinged, yellow to brown in color with 11 scutes and is nearly as long as the carapace.  A key feature in distinguishing this species from closely related members of the Family Kinosternidae is the pie shaped pectoral scutes on the plastron.  The head and neck are brown and may have yellow mottling or spotting while the legs are a grayish-brown and lack additional coloration.  All members of the Family Kinosternidae have musk glands in the skin under the carapace that release pungent secretions.  Males exhibit sexual dimorphism with a blunt spine at the end of the tail and rough scale patches on the inside of the hind legs.  Unlike the adults, hatchling mud turtles have a rough, dark colored carapace with a well-defined mid-dorsal keel.  The plastron of hatchlings ranges in color from yellow to red with darker pigmentation in the center.

Habitat

    The mud turtle can be found in both freshwater and brackish water habitats.  Though they are semi-aquatic, members of the Family Kinosternidae are generally considered poor swimmers therefore they are likely to be seen walking underwater.  They can be found in a wide variety of habitats such as marshes, streams and rivers, ponds, ditches and muskrat lodges although they prefer shallow, soft-bottomed, slow-moving water with plentiful vegetation.      

Breeding 

    Mud turtles are active from April to October.  They breed from mid-March to May and reach sexual maturity at 5-7 years of age.  Courtship and mating can take place either under water or on land.  The musk glands play an important role in courtship as the males will extend their head and gently rub their musk gland on the bridge between the female’s carapace and plastron.  These musk glands secrete pheromones that help prepare the female for copulation, though females may nonetheless be unreceptive to the male’s advances.  If this is the case the female will simply walk away.  When a female rejects a male’s advances he will either move on to a different female or become somewhat aggressive by biting at the female’s neck.  If the female then becomes receptive to the male, he will mount the female and hold on to the rim of her carapace with all four feet.  The male will loop his tail around the female’s tail to align their cloacal openings.  After insemination, the female will lay 1 – 8 small, elliptical-shaped, bluish or pinkish-white eggs in a shallow nest.  Preferred nesting sites are in loose sandy loam soils with vegetative debris.  The eggs hatch in late summer (August and September) although hatchling mud turtles have been known to overwinter in the nest. 

 Distribution in Maryland

Range map adapted from Harris, 1975. 

Links

 http://www.dgif.state.va.us/wildlife/species/display.asp?id=030051

http://herpcenter.ipfw.edu/index.htm?http://herpcenter.ipfw.edu/outreach/accounts/reptiles/turtles/E_MudTurtle/index.htm&2