Essays

Wild On The Prairie: Invertebrates

Jigging urticating tarantulas is fun, not scary

Ranchers and farmers of the Midland Soil and Water Conservation District operate the Sibley Nature Center. Thousands of adults and children visit the center to learn more about our regional flora and fauna. Visitors first tour the building displays, and then hike along trails that wind through a mesquite thicket and by a cattail filled pond lined with trees. A few small animals live inside the Center's laboratory/classroom in cages. One of the most popular is a large female tarantula.

Tarantulas are scary looking. Many people kill them on sight, certain that the fuzzy spiders will jump onto and bite humans, injecting a deadly poison. Nothing is further from the truth. Tarantulas do not jump. They will bite, but the poison is no worse than a bee sting. Over the years, seventy-five thousand Sibley visitors have held a tarantula without suffering a single bite. The spiders teeter across the visitor’s hand, carefully maneuvering over the bumps of knuckles and fingers. A tarantula’s eyes are located on top of the head, so it cannot know it is walking on a human. Most people giggle at the tickle of the hairy feet.

A popular activity while hiking on the trail is “jigging tarantulas.” To jig a tarantula first take a long grass stalk and slide it down a tarantula hole. After the stalk reaches the bottom, jiggle the stalk. When the tarantula grabs it, pull the stalk out. Sometimes the spider rides the grass up and out. Other times, it chases it out.

Finding a tarantula hole is easy. In sandy soils, holes the size of nickels dot the ground up to a hundred or more an acre. In rocky soils, tarantulas will dig under a rock, and more than two hundred per acre can be found.
Once a tarantula has eaten its fill, it often spins a web over the top of the hole, which will then become hidden by the accumulation of windblown sand. A tarantula usually lives in the same hole for years at a time.

Females can live thirty years. At Sibley we visit several tarantulas that have had the same hole for a decade. Male tarantulas mature between the ages of seven and ten years, and then leave their hole to search for a mate. When you see a tarantula out walking, it is usually a mature male. Male tarantulas usually emerge following a rainstorm. It is thought that males find females by sensing their pheromones, which are carried farther by moist air. Sometimes hundreds of male tarantulas will be found crossing the road after a rain. Look at the front legs (not the pedipalps in front of its mouth that look like short legs). A mature male can be identified by the small spurlike projections on the second elbow.

If you find a tarantula hiding under a rock, keep your eyes open for a Narrow-mouthed Toad. These tiny toads - gray with black dots - have a symbiotic relationship with tarantulas. Toads have moist skin that contains various chemical compounds. Compounds found in the skin of Narrow-Mouthed Toads act as a miticide, protecting the tarantula from infestations of these tiny parasites. In the early 1970’s, Texas Parks and Wildlife Magazine ran a series of pictures starring a toad and a tarantula. When a snake threatens a toad, the toad runs and hides under a tarantula!

When a tarantula is frightened, it rears up, waving its front legs. If it is feels extremely threatened, the tarantula will rub its abdomen with its hind legs. This action pulls some hair off of the abdomen which then floats into the air. The hair causes itching, especially if it lands in the eyes of the small animal bothering the tarantula. Sometimes a tarantula is found with a large abdominal bald spot resulting from this “urtication.”

Tarantulas are easily kept as pets. Fans of this fascinating arachnid have formed a Tarantula Society, based in Carlsbad, New Mexico. Public interest has increased what is currently known about tarantulas. So far as I can determine, no one really knows how many species of tarantula live in Texas, or each species' distribution.