The western desert tarantula (Aphonopelma chalcodes) also known as the Arizona blond tarantula and Mexican blond tarantula are common in the deserts of southern California, Arizona and New Mexico.

Desert tarantulas, like other tarantula species, have a body covered entirely with hair. Like all spiders, they are divided into two body segments: the cepholothorax and the abdomen. The cepholothorax is gray to dark brown and the abdomen is dark brown to black. Iridescent hair forms a pad below the tip of each of the eight legs. Tarantulas inject poison into their victims by biting them with fangs on the end of the chelicerae (a pair of appendages in front of the mouth).

Desert tarantulas are reclusive, nocturnal spiders. They live the majority of their lives alone. They make no sounds; they communicate primarily by touch because they have poor vision. They usually hide in their burrows, under rocks, or in abandoned holes during the daylight hours. They may live in the same burrow for decades. They hide during the day because they are more vulnerable to predators during the day and because their prey is mostly nocturnal.

Tarantulas prey on insects, caterpillars, millipedes, lizards, mice and other spiders. Although the desert climate is one of extremes, with temperatures often reaching as high as 120 degrees Fahrenheit in the summer and dipping below freezing in the winter, desert tarantulas require little water, obtaining moisture from their prey. Tarantulas have few natural predators – birds and tarantula wasps are the most common. If a desert tarantula feels threatened, it raises up on its hind legs, and stretches its front legs in a threatening posture. It may also brush the top of its abdomen with its hind legs, which dislodges poisonous hairs that can irritate the eyes or skin or even cause partial blindness in an attacker.

While a desert tarantula can grow quite large compared to other spiders (with a body diameter reaching a little less than 2 inches to about 2 ½ inches), it does not pose any significant danger to humans. Although its bite is painful, it is not highly poisonous. The venom is similar to that of a mosquito or a bee sting.

In the fall, after heavy rains, mature males (approximately 8 to 10 years of age) emerge from their burrows seeking females. While some males are eaten after mating, those who survive have a short lifespan, living only two or three months after reaching maturity. Female tarantulas may live for as many as 20 years (and even longer in captivity).

Some people are tempted to keep a desert tarantula as a pet due to its typically gentle nature and easy maintenance. My philosophy is, why not let them live their lives where and how they were meant to? You will enjoy encounters with these amazingly beautiful spiders out in the desert all the more if they are infrequent and catch you by surprise.

Linda Castro is a nature enthusiast and animal lover.  She is the Desert Field Organizer for the California Wilderness Coalition and serves on the board of the SCV-based Community Hiking Club.  Her commentaries relate to California’s deserts.

Photo courtesy Rowland Willis