Oaxaca Mud Turtle

1 Overview

The Oaxaca Mud Turtle (Kinosternon oaxacae) is a type of mud turtle with a summer-dormancy habit, burying itself in mud in summer to cool down, which is why it is called a mud turtle. It lives in slow-moving rivers, hunting fish and shrimp in the water, and is an omnivore that leans carnivorous.

Chinese name: Oaxaca Mud Turtle

English name: Oaxaca Mud Turtle

Latin name: Kinosternon oaxacae

Kingdom: Animalia

Phylum: Chordata

Subphylum: Vertebrata

Class: Reptilia

Order: Testudines

Family: Kinosternidae

Genus: Kinosternon

Species: Oaxaca Mud Turtle

Distribution: The Oaxaca Mud Turtle is distributed only in the Pacific coastal basins of Río Colotepec and Río Tonameca, and in Mexico.

Appearance: A relatively large mud turtle, reaching about 17.5 cm in length. The carapace is generally brown or black.

Reproduction: Oviparous. Females lay two clutches per year (mid-May to mid-June or early July), about 1–4 eggs each, usually in sand or shallow burrows near riverbanks.

Behavior: Lives in non-permanent coastal-plain waters and stable hill-country lakes.

Diet: Omnivorous; in the wild it hunts any animal smaller than itself in the water—fish, shrimp, even other turtles—and occasionally eats aquatic plants or fallen fruit.

2 Physical Characteristics

The Oaxaca Mud Turtle has a small head and an oval carapace with an inconspicuous dome, in varied colors; the black carapace pattern contrasts sharply with the scute color. The plastron is brownish-red with black streaks complementing the carapace.

The Oaxaca Mud Turtle is a relatively large mud turtle, reaching about 17.5 cm. The carapace is generally brown or black, possibly with black spots or black seam lines, and the scutes show slight overlap. Additionally, the carapace bears three distinct vertebral keels.

The Oaxaca Mud Turtle’s plastron and bridge are usually yellow or brown with black seam lines, occasionally mixed with some brown blotches. The axillary and inguinal scutes touch each other. The head is small, dark black on top, with intricate net-like stripes on the sides and a pale yellow underside with some black spots. The strong upper jaw is hooked; the upper and lower jaws may have black stripes; the chin bears 3–4 pairs of barbels. The limbs are brown or gray outside and cream inside. The tail is mainly brown and tan with a horny terminal spur. Males have a concave plastron and a long, thick tail; females have a flatter plastron and a shorter tail.

3 Care & Husbandry

The Oaxaca Mud Turtle requires rather careful keeping, as it is fussy about environment and husbandry. When the temperature drops to a certain point it enters hibernation, after which it may become picky and sensitive, so care methods need extra attention.

Water quality is not too demanding for the Oaxaca Mud Turtle; it quickly adapts to ordinary home tap water that has been left to stand, though fresh straight-from-the-tap water is absolutely unsuitable. This turtle is highly aquatic, so a filter is best—its scent in the water makes it feel secure and helps maintain water quality and routine cleaning.

Regarding temperature, like most aquatic turtles, the suitable water temperature is 25–30°C. At the right temperature its coloration looks good; below the normal physiological temperature it darkens, moves slowly, and eats little. Temperature changes directly affect the Mexican giant musk turtle’s coloration. Basking is vital—at a suitable ambient temperature allow some sunlight for 10–20 minutes (not daily); if sunlight is inconvenient, use an artificial UVB tube for 4–8 hours (also not daily).

4 Natural Habitat

The Oaxaca Mud Turtle likes a warmer environment, but if kept outdoors, ensure a shaded spot. It can hibernate outdoors on its own, but only in southern China; in the north it would freeze to death, so keep it indoors in winter.

Captive-bred Oaxaca Mud Turtle juveniles are often found in the market. In summer, raised in a large outdoor enclosure free of predators and planted with edible shrubs and weeds, it thrives; the enclosure should also have a hiding place and a shallow water dish. This turtle is a digger, so fencing should extend underground to prevent escape.

Indoors, the Oaxaca Mud Turtle needs a spacious turtle table and other equipment, including a heat source and a UVB tube or a bulb that provides both heat and UVB, plus landscaping features for shelter and climbing and a shallow water dish. The temperature at the basking spot should be 90–95°F (32–35°C), while the enclosure should also have a cooler zone so the turtle can regulate body temperature and metabolism.

Use a 50/50 mix of topsoil and children’s play sand as substrate, and build areas of dried fruit-tree grass for feeding and digging. Note that juveniles need a more humid environment to prevent dehydration. If the enclosure is large enough, simply add a more humid soil area, a damp hide, or a burrow.

5 Feeding & Husbandry

The Oaxaca Mud Turtle is not strict about food choice and generally prefers meat; in the wild it is also preyed upon by some meat-eaters. In captivity it easily develops post-hibernation anorexia—why?

1. Food Selection

In the wild it hunts any animal smaller than itself—fish, shrimp, even other turtles—and occasionally eats aquatic plants or fallen fruit. Although rare, cannibalism has been observed. Feed fresh animal prey such as small fish, shrimp, snails, clams, earthworms, and meat. When young it is often taken by wading birds or predatory fish; for adults, raccoons are the main predators. Giant alligator snapping turtles also prey on juveniles and adults. Their lifespan is generally 30–40 years.

2. Post-Hibernation Anorexia

After hibernation, the most common problems in juveniles are ‘post-hibernation anorexia,’ dehydration, inability to open the eyes, limb weakness, mouth inflammation, respiratory trouble, skin disease, weakness from vitamin deficiency, and colds. Research shows that after hibernation ends, gradually raise temperature and humidity day by day, then let the juvenile first eat moisture- and sugar-rich fresh produce such as tomatoes, bananas, and grapes, followed by smaller insects or fish, or even fresh liver. Normally it returns to normal feeding within 1–2 weeks.