Pinnacles National Monument - Tarantulas

An autumn visit to Pinnacles National Monument is often rewarded with a sighting of one our most fascinating creatures, the tarantula. September and October are the prime months to see male tarantulas ambling resolutely day and night in search of mates. They investigate every potential burrow, looking for a female ready to lay eggs in her specially prepared nest.

Why don"t you see tarantulas during the rest of the year? They are always here, but they are usually much more secretive. They spend the day in their burrows, emerging to hunt only at night. At any time of year, if you look carefully on the ground for small holes lined with silk, you might see a tarantula looking back at you! You"d be surprised how small a hole a tarantula can fit into.

Tarantula X-ing
Tarantulas are commonly seen crossing roads. Please obey posted speed limits and watch the road to avoid running over tarantulas and other wildlife.

Part of the Food Web
Tarantulas eat a variety of insects and other invertebrates, and possibly lizards, snakes, and small rodents. They bite their prey, injecting it with digestive juices. Then they mash it with their strong jaws, and drink the liquid. After a large meal, a tarantula may wait several months before feeding again. Tarantulas are in turn eaten by lizards, snakes, birds, and tarantula hawks.

Tarantula Hawk
If you think the way a tarantula feeds is gruesome, wait till you hear about the tarantula hawk. Nearly the size of a hummingbird, it is our largest member of the spider wasp family. It is stunning with its shiny blue-black body and smoky orange wings. You can often see them in summer and fall visiting flowers.

When the female tarantula hawk is ready to lay her eggs, she leaves the flowers behind and goes on the hunt for a tarantula. Upon finding one, she paralyzes it with a sting. Even though the tarantula is several times her own weight, she drags it to a hole, lays her eggs on it, and buries it. The eggs soon hatch into wasp larvae which slowly devour the paralyzed tarantula alive, from the inside out.

Self Defense
If provoked, the tarantula may inflict a painful bite, about like a bee sting. (The tarantula hawk"s sting is much more painful.) However, the tarantula has a rather gentle nature, and rarely uses its fangs except to catch prey. When alarmed, it may raise its front legs and its abdomen to look aggressive. It may also release stinging hairs from its abdomen. These hairs irritate the skin of an attacker by digging themselves in with hundreds of tiny hooks.

Tarantula Web
A tarantula spins silk, but not in the form of a web for catching food. Instead, the silk is used to line the burrow, and by the female to line the nest and cover the eggs.

Walking up Walls
Web-spinning spiders have three claws, the middle one being used for grasping the web. In tarantulas, the middle claw is replaced by a dense pad of hairs. Each of these hairs splits into hundreds of microscopic branches, called "end feet." The combined surface effects of all the end feet allow the tarantula to walk on walls and even ceilings.

Spider Senses
Tarantulas have eight eyes, although they probably can"t see very well. They have no ears, although they have thousands of fine body hairs which allow them to feel the vibrations of passing prey. They taste with special "taste hairs" near the feet and around the mouth. They probably smell with pits on top of the feet.

Life Span
Tarantulas reach maturity at about 10 years. Males die within a year of mating, and are sometimes eaten by the female before mating. Females may live over 20 years.

What"s in a Name?

What ho! What ho! This fellow is dancing mad! He hath been bitten by the Tarantula.
- Edgar Allan Poe

"Tarantula" was the name originally given to the southern European wolf spider (Lycosa tarentula) and referred to the town of Taranto, Italy. It was believed that the bite of this spider would cause the disease of tarantism, the symptoms being uncontrolled weeping and jumping about. The victim would finally go into a wild dance called the Tarentella. This dance is now a popular Italian folk form and has inspired several famous composers to write classical versions. Scientists have not studied the tarantulas of California well enough to be able to give the tarantula found at Pinnacles a specific scientific name. It is most likely in the genus Aphonopelma. Do you know anybody who would like to study our tarantulas?

Boy or Girl?
Most of the tarantulas you encounter are males out wandering in search of females. If you are lucky enough to meet a tarantula face-to-face, look for the tibial spur on each front leg behind the "knee." Only males have this claw-like appendage.

Other Spiders at Pinnacles
We know very little about the spiders of Pinnacles. There are undoubtedly hundreds of species, many of them undescribed. Plus, there are many spider relatives here: ticks, mites, scorpions, sun scorpions, pseudoscorpions, and harvestmen. Some of the more conspicuous spiders at Pinnacles are:

Hairless tarantula: This spider is about half the size of the more commonly seen tarantula. It lacks stinging hairs, and it is quite aggressive.

Green lynx: Look for this spider in the fall on small flowering shrubs, where it catches insects visiting the flowers. It can be very hard to see, but once you find one, you will often find more nearby. Also look for its white egg sacs.

Black widow: This well-known, highly poisonous spider advertises "danger" with the red hourglass on its underside. Its web is exceptionally strong.

Crab spiders: Look carefully on flowers for these spiders. They hold their long front legs wide open, waiting to snatch their flower-visiting prey.

Diguetid spiders: Although you may never see one of these spiders, their webs are quite conspicuous in California buckwheat shrubs. Look for a vertical tube filled with debris, above a flat cone of threads.