Reptiles of North Carolina

Scientific Name:	Common Name:		Family (Alpha):

NC Records
Kinosternidae Members:
Kinosternon subrubrum - Eastern Mud Turtle

Photo: Steve Hall

Photo: Z. Lunn

Photo: Jane Wyche

Taxonomy

Class: Reptilia

Order: Testudines

Family: Kinosternidae


Taxonomic Comments: Seven species of Kinosternon are currently recognized in North America north of Mexico (SSAR, 2016). Two of these species occur in North Carolina.
Species Comments: Two subspecies are currently recognized (SSAR, 2016), with only the Southeastern Mud Turtle (K. s. subrubrum) found in North Carolina (Powell et al., 2016).

Identification

Basis for Records: Good quality photographs of the head and shell of well-marked individuals are usually sufficient to identify the species. A photograph of the plastron will separate this species from the Musk Turtles.

Field Marks: This species is very similar to the Striped Mud Turtle but the skin is usually a lighter shade of gray and it lacks the yellowish line connecting the nostril to the orbit (Palmer and Braswell 1995). The carapace is also usually unmarked.

Morphological Features: Both species of Mud Turtles are recognizable by their hinged plastron and by the triangular shape of its pectoral scutes. In Musk Turtles, the pectoral scutes are rectangular or quadrangular (Palmer and Braswell, 1995). The carapace is narrow, elevated, and smooth. Males have larger and longer tails, with the vents located posterior to the rear edge of the shell.

Technical Reference: Palmer and Braswell (1995); Ernst and Lovich (2009)

Field Guide Descriptions: Beane et al. (2010); Powell et al. (2016)

Online Photos: Google iNaturalist GBIF

Observation Methods: Mud Turtles rarely bask and are usually observed either foraging underwater or moving overland.

Distribution in North Carolina

Distribution Comments: This species is absent from the mountains but otherwise occurs across the state, including the barrier islands.
Distribution Reference: Palmer and Braswell (1995); NCMNS Herpetology Collection Database (accessed 2023-01)
County Map: Clicking on a county returns the records for the species in that county.

Key Habitat Requirements

Habitat: Eastern Mud Turtles occupy a wide variety of aquatic and wetland habitats, including sandy bottomed streams, farm ponds, vernal pools, meadows, wet pastures, swamps, and brackish marshes (Palmer and Braswell, 1995; Beane et al., 2010). They also spend significant amounts of time in the terrestrial habitats located adjacent to their wetland and aquatic sites (Fraser et al., 1991).

Environmental and Physiological Tolerances: Eastern Mud Turtles are at least tolerant to some degree of low levels of salinity, allowing them to occupy brackish marshes and to colonize the barrier islands.

Adaptations to Natural Disturbances: Some individuals burrow into pond substrates in response to drought, but they have been commonly observed leaving ponds as they dry out, moving overland to other sites that still have water or aestivating on land (Ernst and Lovich, 2009).

Biotic Relationships: Eastern Mud Turtles are highly omnivorous, feeding on a wide range of crayfish, snails, insects, and other aquatic invertebrates; fish, tadpoles, and other small vertebrates and their eggs; green algae and a variety of aquatic plants (Ernst and Lovich, 2009). A large number of nest predators have been identified, including Kingsnakes. Adults are preyed upon by herons, carnivorous mammals, snakes, and alligators.

Life History and Autecology

Breeding and Courtship: Reproductive maturity is reached in four to seven years in males, and five to eight in females (Ernst and Lovich, 2009). Mating takes place from mid-March to May and is usually done in the water. Sperm may be stored for use in fertilizing several clutches of eggs.

Reproductive Mode: Nesting occurs mainly in May and June. Nests are usually dug in bare ground, not far from water (Ernst and Lovich, 2009). Sandy or other friable soils are preferred but mounds of vegetation -- including Alligator nests -- may be used. Clutches of 2-4 eggs are common, but with a range of 1-9 eggs observed.

Aquatic Life History: Although not considered strong swimmers, Cordero et al. (2012) found that Eastern Mud Turtles can occupy very large aquatic home ranges in areas possessing extensive shallow water habitats. They recorded mean estimates of home-range size of 18.6 ± 23 ha in 2008 and 16.3 ± 16.3 ha in 2009. The maximum aquatic distances of travel they observed was 815 ± 455 m in 2008 and 774 ± 331 m in 2009.

Terrestrial Life History: Eastern Mud Turtles spend significant amounts of time on land, where they both aestivate and hibernate, and where they can forage at least to some extent; they were considered to be the most terrestrial species of aquatic turtle of five species associated with a Carolina Bay in South Carolina (Fraser et al., 1991).

General Ecology

Population Ecology: This species may live from 20 to 50 years (Fraser et al., 1991).

Adverse Environmental Impacts

Habitat Loss: Draining and/or conversion of shallow wetlands is a major human-caused impact to this species.

Habitat Fragmentation: This species, like other herps, is highly vulnerable to being killed on roads and highways, consequently, are a major cause of habitat fragmentation in this species.

Status in North Carolina

NHP State Rank: S5

Global Rank: G5

Environmental Threats: The increase in temperatures associated with climate change may affect the sex ratio of this species, which, like other turtles, is dependent on temperatures within the nest (Stemle, 2017). Rising temperatures favor the development of females and at some point males may become so scarce as to be a limiting factor.

Photo Gallery for Kinosternon subrubrum - Eastern Mud Turtle		27 photos are shown.
	Recorded by: T. Chisholm Iredell Co. Comment:	Recorded by: T. Chisholm Iredell Co. Comment:
	Recorded by: Stephen Hall, Meriel Goodwin, David George, Gary Perlmutter, Blanka Aguero, Lisa Gatens Chatham Co. Comment:	Recorded by: L. Eckart Carteret Co. Comment:
	Recorded by: C. Teague Beaufort Co. Comment:	Recorded by: K. Bischof Beaufort Co. Comment:
	Recorded by: Z. Lunn Scotland Co. Comment:	Recorded by: Z. Lunn Scotland Co. Comment:
	Recorded by: Erich Hofmann Craven Co. Comment:	Recorded by: K. Sanford Camden Co. Comment:
	Recorded by: K. Sanford Camden Co. Comment:	Recorded by: K. Bischof Beaufort Co. Comment:
	Recorded by: K. Bischof Beaufort Co. Comment:	Recorded by: K. Bischof Burke Co. Comment:
	Recorded by: K. Bischof Burke Co. Comment:	Recorded by: C. Edwards New Hanover Co. Comment:
	Recorded by: C. Edwards New Hanover Co. Comment:	Recorded by: C. Edwards New Hanover Co. Comment:
	Recorded by: W. Stanley Cumberland Co. Comment:	Recorded by: Jane Wyche Gates Co. Comment:
	Recorded by: K. Bischof Beaufort Co. Comment:	Recorded by: K. Bischof Beaufort Co. Comment:
	Recorded by: K. Bischof Beaufort Co. Comment:	Recorded by: B. Bockhahn Wake Co. Comment:
	Recorded by: Steve Hall Orange Co. Comment:	Recorded by: Steve Hall Orange Co. Comment:
	Recorded by: Steve Hall Orange Co. Comment:

Kinosternon subrubrum - Eastern Mud Turtle

Photo Gallery for Kinosternon subrubrum - Eastern Mud Turtle

27 photos are shown.