Baja California Slider Turtle

Baja California Slider Turtle, Trachemys nebulosa nebulosa

Baja California Slider Turtle, Trachemys nebulosa nebulosa. Turtle collected out of the San José River Lagoon, San José River del Cabo, Baja California Sur, August 2012. Size: 25 cm (10 inches).

The Baja California Slider Turtle, Trachemys nebulosa nebulosa, is a medium sized turtle that is a member of the Emydidae family of Freshwater Pond and Marsh Turtles. The Emydidae family is small with a worldwide population with fifty species placed in ten genera. There are seventeen species in the Trachemys genus. There are two subspecies of Baja California Slider Turtle: Trachemys nebulosa nebulosa, resides in the states of Baja California and Baja California Sur, and Trachemys nebulosa hiltoni, resides in the states of Sinaloa and Sonora in mainland Mexico. The Baja California Slider Turtle is known in Mexico as Tortuguita Del Rio.

The Baja California Slider Turtle is easily differentiated from other turtles by its clawed digits, non-elephantine hind limbs, and wide, light-colored suborbital patch. Their shell is smooth, rounded posteriorly, straight anteriorly, and longer than it is wide. In addition, their shell has a low lateral profile and can reach 37 cm (14.5 inches) in length. The dorsal surface of their shell is dark in color and the vertebral, costal, and marginal scutes have dark brown spots surrounded by lighter margins. The ventral side of their shell is yellow with symmetrical black markings. Their head is large, triangularly shaped, and covered with smooth skin. The top of their head is olive with indistinct pale yellow markings and their chin and throat are lighter with central yellow markings. A pair of yellow stripes extend anteriorly across their local jaw and onto their upper jaw. They have large eyes and their nostrils are located high on their protruding snout. Their forelimbs are short and flat with five clawed digits, while their hind limbs are short, robust, and flattened with five fully webbed digits. Only the first four digits on their hind limbs have claws. Their tails are moderately long with males having longer tails than females. Their body is covered with a series of yellow stripes including the forelimbs (but not the hind limbs) and from the base of the foot to the base of the tail. 

The Baja California Slider Turtle prefers large bodies of water with muddy bottoms and can be seen basking on emerged rocks and floating logs. They are most active between mid-March and October, and during the winter months bury themselves in mud. The Baja California Slider Turtle is poorly studied with very limited information available about their lifestyle and behavioral patterns including specific details on age, growth, longevity, movement patterns, diet, habitat use, and reproduction.

The Baja California Slider Turtle has an exceedingly limited geographic range. They are currently found from San Ignacio southward throughout Baja California Sur. They were endemic exclusively to the San José Rio basin in the greater Cabo San Lucas area (where they are now exceedingly rare due to overfishing) but as early as the late 1700’s they were transported northwards by natives to provide a continuing food source.

From a conservation perspective the Baja California Slider Turtle has not been formally evaluated, however, their populations and range are limited and their populations are believed to be in decline. They are still consumed in remote areas of the Baja by native people. This species is extremely wary of humans and difficult to approach. They make good house pets but are high maintenance.