Baja California Mole Lizard (Bipes biporus)
Identification: 7-9.5 in. (18-23.8 cm). A pinkish cylindrical body with annulations of scales present on the entire body behind the head. The head is rounded and short and no neck is present. The body is elongated and wormlike with two well developed hypertrophied limbs present behind the head which can be placed within recessed areas alongside the body. Expanded ulnar scales are present on the limbs and these undoubtedly assist in moving soil as it digs through substrate. The snout is rounded and the vestigal eyes are located on either side of the head beneath a transluscent scale. No ear openings are present.
The tail is short, blunt and will break off along fracture planes if grabbed by a predator. However, unlike many lizards, Bipes cannot regenerate its lost tail.
Range: Bipes biporus occupies a geographic distribution that includes the western portion of the southern half of Baja California, west of the Peninsular ranges, rfom approximately 17 km north of Jesus Maria, where the Sierra Colombia contacts the Pacific coast, south to Cabo San Lucas (Papenfuss, 1982). At the Isthmus of La Paz, its distribution extends east across the low sandy flats and contacts the Gulf coast at Bahia de La Paz (Grismer, 2002).
Habitat: In urban settings this small reptile can be found by searching beneath debris, litter and by flipping rocks in vacant lots between houses and buildings. In more naturalistic settings they may be encoutnered by digging up the bases of small shrubs and grasses and inspecting the soil within the root matrixes.
Predators and Defense: Like any small reptile, Bipes biporus is vulnerable to predation from various larger animals including but not limited to large predaceous arthropods and snakes. Click here for a publication regarding the prey items consumed by the Mountain kingsnake (Lampropeltis zonata).
When picked up Bipes biporus will engergetically jump and writhe in a similar fashion to earthworms attempting to avoid the grip of a predator. They will also release a foul smelling musk from the cloaca in the same fashion as snakes and many lizards.
The hypertrophied front limbs complete with well developed claws used for digging by Bipes biporus.
Notice the overhanging flesh just behind the point of insertion of the front limb. This allows for the Bipes
effectively reduce its circumference while moving through a tunnel.
These distinctive markings leave the tell tale sign of Bipes activity. Note the burrow entrance at the upper left side of the trail.
Following capture this surprised specimen contorted and writhed its body into an odd position. All the while it kept the head hidden and exuded musk from the cloaca.