Baja California Bark Scorpion

Baja California Bark Scorpion, Centruroides explicauda

Baja California Bark Scorpion, Centruroides explicauda. Scorpion collected from within a residence in the greater Los Cabos area, Baja California Sur, May 2018.  Length 3.2 cm (1.3 inches).

The Baja California Bark Scorpion, Centruroides explicauda, is a member of the Buthidae family of arrowbreasted scorpions. The Buthidae family is the largest family of scorpions which has one thousand three hundred thirty-nine individual species placed in one hundred genera. The genus Centruroides contains between seventy and eighty species, many of which have not been fully characterized and all are indigenous to the Americas and thought to cause fatal envenomation. The species name explicauda means “slender tail”. The Baja California Bark Scorpion is known in Mexico as Alacrán de la Corteza Bajeño.

The Baja California Bark Scorpion is a medium sized scorpion that reaches a maximum of 5.1 cm (2.0 inches) in length and has slender pincers and a slender tail. They may be pale yellow to yellowish-brown in color, with varying banding across the body. Like other slender clawed scorpions, this species is capable of delivering a sting with a strong neurotoxin.

The Baja California Bark Scorpion takes shelter during daylight hours under loose tree bark, leaf litter, and rocks. At night, they prowl about hunting for insects, spiders, centipedes, and other scorpions. In turn, they are preyed upon by bats, large centipedes, lizards, owls, mice, shrews and tarantulas. Due to the dry environment in which they are found, it is not uncommon for them to go without food or water for extended periods of time.

The Baja California Bark Scorpion is very similar to the Arizona Bark Scorpion, Centruroides sculpturatus. Historically they were considered to be different simply based on geographic locations, but they were still classified together as Centruroides explicauda. However, very recently, they are again considered to be separate species due to DNA evidence. This confusion has caused incorrect data regarding geographic range and envenomation statistics. It is possible that Centruroides explicauda is significantly less dangerous than Centruroides sculpturatus. The Baja California Bark Scorpion can be distinguished from other scorpions by two main differences. First is the presence of a subaculear tooth at the end of their tail just below the stinger. Second, they rest their tails on the ground, as opposed to other scorpions that rest their tails in an arch above their back. 

The geographic range of the Baja California Bark Scorpion has not been well documented. Currently, any bark scorpion found on the Baja Peninsula seems to be considered Centruroides explicauda. They are also thought to be found in Arizona, California, Sonora Mexico and the Islands of the Sea of Cortez in locations where the Arizona Bark Scorpion, Centruroides sculpturatus, and other Bark Scorpions are also present.


From a conservation perspective the Baja California Bark Scorpion has not been formally evaluated. Since they have been around for centuries and are of limited interest to most they should be considered to be of Least Concern, with stable, widely distributed populations. 

Bark scorpions are the most likely species of scorpion to enter dwellings because they can ascend block walls and stucco. They are attracted to moisture in and around homes and only need a crack of 1.6 mm (1/16 inch) to enter a home. When encountered they should be handled with EXTREME CAUTION as their sting can cause anaphylaxis and fatalities in humans. Children under age five and the elderly are at greatest risk of fatalities. Healthy adults are not generally considered at risk.