Turtle, Florida Mud


Kinosternon subrubrum steindachneri


The carapace (upper shell) length is 2.75 – 4.92 in. (70-125 mm) with the plastron (lower shell) relatively large and with two movable hinges rather than one. The color of the domed, smooth carapace can be brown, olive, yellowish, or black; in juveniles the carapace can have three longitudinal keels (raised ridges). The head and neck are generally brown with a variety of lighter colored stripes or mottling.  Unlike other species of Kinosternon, the ninth marginal scute (plate or lamina) does not extend dorsally, and the first vertebral scute does not contact the second marginal. This subspecies has a much smaller bridge than the Eastern Mud. Males of this form are larger in body size than females.

Family

Kinosternidae

Order

Testudines

Class

Reptilia

Range

Peninsular Florida (it intergrades with the Eastern Mud, Kinosternon s. subrubrum, in the northern part of the state and then the Eastern and Mississippi mud turtle, K. s. hippocrepis, in the panhandle)

Habitat

Lentic or slow-moving freshwater systems, with a preference for well-vegetated, sandy-bottomed littoral zones.

Life Expectancy

In the wild, the common mud turtle, Kinosternon subrubrum, may live 40 years.

Sexual Maturity

Females – 5 years (1825 days); males – 4 years (1460 days)

Diet

In the wild they eat mollusks, insects and their larvae, small fish, aquatic plants, algae and crayfish; in the Zoo they are fed a scientifically developed, commercially available turtle food and worms.

Status

IUCN – Least Concern

Behaviors

It is active night or day, with a possible reduction in activity during the summer. Adults are omnivores and opportunistic feeders. Mating occurs from mid-March through May with copulations occurring earliest in the south. Mating usually takes place under water but sometimes occurs on land. Most nesting occurs during June but has been observed from February through September in various parts of the range. The nesting site usually is open ground not far from water. Sandy, loamy soils are preferred, but piles of vegetable debris also are used. In some localities mud turtles often nest in muskrat tunnels. Eggs have been found on the surface of the ground and under piles of boards, and, in the south, alligator nests are often used. The completed nest usually is a semicircular cavity 2.9 – 4.9 in. (75 -125 mm) deep and entering the ground at about a 30° angle. Clutches vary from one to nine eggs; normally two to five, and most commonly three to five eggs are laid. At least three clutches are laid annually. The eggs are elliptical, pinkish white or bluish white and brittle shelled, 0.8 – 1.1 in. (22 - 29 mm) long and 0.5 – 0.7 in. (13 -18 mm) wide. Hatching occurs after about 100 days. The hatchling carapace (0.7 – 1 in.; 20 - 27 mm) is shaped like that of the adult but has a vertebral keel and two weak dorso-lateral keels, is rough, and is not depressed anteriorly or sharply turned down posteriorly. It is dark brown or black, with light spots along the marginals. The plastron is irregularly mottled with orange or red, and the hinges are poorly developed. Hatchling skin is brown or black. Mud turtles, in general, are quite terrestrial. They leave the water in early summer, forage on land for a short period, and then burrow to aestivate during the hot weather. They may remain underground until the next spring.

Adaptions

The Florida mud turtle’s reduced plastron may be in response to a more extensive aquatic existence. Two strong plastral hinges enable this species to withdraw all limbs, the head and neck and tightly close them within the shell for protection.

Special Interests

In central Florida, K. s. steindachneri is sensitive to certain kinds of habitat modifications. Habitat destruction and modification, such as roads adjacent to canals and ditches, negatively impact what is otherwise an uncommon and ecologically poorly-studied Florida endemic subspecies.

Folklore

Conservation

Jacksonville Zoo History

Florida mud turtles have been part of the Jacksonville Zoo’s animal collection since 2001.

Exhibit

Wild Florida