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Yellow Mud Turtle

(Kinosternon flavescens) Special Concern

Identification: Shell hard, smooth, oval-shaped, sometimes with extensive attached algae; throat yellow, with several nipplelike projections; lower shell with 11 shields (shield under neck may be partially divided) and with two crosswise hinges, allowing partial closing of the shell; all toes webbed; upper shell up to about 18 cm (7 inches) long, usually less than 14 cm (5.5 inches).   Mature male: Lower shell slightly concave; two patches of conspicuous, rough scales on inner surface of each hind leg; tail thick, tipped with a horny nail, extends well beyond rear edge of upper shell, usually curled to one side; grows to larger size than female and has relatively larger head and claws that are longer and more curved. Mature female: No rough scale patches on hind limbs, tail very short, barely reaching rear edge of upper shell. Hatchling: Upper shell usually less than 25 mm (1 inch) long; lower shell boldly black and yellow, black dot on rear border of upper shell scutes.

Colorado Distribution: Localized areas along the eastern margin Colorado. Fairly common in a few areas, generally scarce.    

Habitat: Permanent and intermittent streams, permanent ponds, irrigation ditches, soggy fields, marshes, and surrounding grasslands and sandhills; readily colonizes isolated temporary ponds and rain pools away from permanent water. Some spend considerable time burrowed in sandhills in summer.    

Life History: Females burrow and nest in soft soils up to a couple hundred yards from water, mainly in June but sometimes into July. Hatchlings overwinter on land, then  emerge and head to water the following spring. Most hatchlings die in their first year, but survivors commonly live 25 years or more.