Female tarantulas may live as long as 20 to 25 years

By George Seymour Outdoor California Writer

In mid-August one year I set a trapline for coyotes in the foothills of the Sierra Nevada in Tuolumne County. The line was extended into roughly a fifty‑mile loop, north and south, and ran from two to three thousand feet in eleva­tion. I drove the abandoned railroad cuts and little‑used logging roads each day tending my traps. I was aware of the increasing number of large hairy spiders on and cross­ing the roadways every day. I recognized them as taran­tulas. By the end of the month, I could see as many as six or eight a day, indicating a mass migration. I knew this was the time of year when tarantulas were commonly seen moving around in areas in which they occur, but what I didn't know then was that the darker colored ones were probably males searching for a mate. The females are seen less frequently for in daylight they remain in their bur­rows or other hiding places.

Different species of this large spider occur in many parts of the world, the largest being a tropical spider found in South America. It may attain a span of seven inches and is agile enough to catch small birds. The ones found in

North America occur in the southern and southwestern states, including the dry and warmer parts of the southern half of California. These are smaller and have a body length of less than 2 inches and a leg span of from 3 to 4 inches. There is a wide color variation, from a soft tan, through reddish brown to dark brown.

They are all quite fearsome in appearance with their long hairy legs and body covered with an almost mouse like fur. Most people look at them with loathing; fearful that they may jump up and bite. Actually, they can only jump forward a few inches. For the most part they are harmless creatures. Even if through carelessness a bite should occur, the venom when injected into man causes only slight swelling, with some numbness and itching which disappears in a short time. The chances of being bitten are so few that one has little need to worry.

A tarantula is interesting to watch for it, is a deliberate walker, picking its steps with the greatest race and cau­tion. In spite of its loitering gait it can cover considerable distance in a day's time. People sometimes pick up these

large slow-moving hairy spiders and let them walk over their hands and arms. Some are even kept as pets. Howev­er, you should be gentle and not restrain them forcibly, for they are capable of inflicting a painful, although not dan­gerous wound with their sharp fangs. The venom, which is injected through the fangs, is as a rule harmful only to the small insects that it captures for food.

The tarantula, like all its allies, does not spin a web to capture its prey, but catches it by activity and speed afoot. It feeds primarily on small insects: grasshoppers, beetles, sow bugs and other small spiders. Upon seizing its prey, it kills it with the venom. Through the wound made by the fangs it injects a fluid from its mouth which digests the victims outside the spider's body. This fluid reduces the prey to a consistency where it may be sucked in by the spider with the aid of its strong stomach muscles. It is then absorbed in the tarantula's stomach.

The tarantula prefers to live in dry, well-drained soil. If the soil is suitable, the female digs a deep burrow which she lines with silk webbing. This helps prevent sand and dirt from trickling in. Otherwise, they hide in cracks in logs and under any loose‑lying debris. In winter she covers the entrance to her home with a plug of leaves and silk, and lies dormant in her "den" until the return of spring. She also uses the burrow as a safe retreat for moulting and guarding her cocoon, and the newly hatched young in its depth.

Tarantulas are normally long‑lived creatures. They do not reach sexual maturity for about 10 years. During this time they undergo a series of moults, and until they reach maturity you can't tell the male from the female. The mature male is quite dark, nearly black, while the mature female is brown. The degree of coloring varies with the species and geographical location. Upon maturity the males abandon their burrows and go forth to seek a mate.

Apparently, that was the fall movement of tarantulas I witnessed in Tuolumne County.

After mating, the male lives only a short time. It may die a natural death or be eaten by the female, sometimes even before mating can occur.

When it comes time for egg laying, the female spins a large sheet of webbing on which she deposits numerous large pearly white eggs. They are covered by a second sheet of webbing which is tightly bound at the edges. She guards this flattened egg sac or cocoon‑carefully for six or seven weeks until the eggs are hatched. The baby taran­tulas stay in the mother's burrow for a week or so before they go out and establish dens of their own.

Some females may live as long as 20 or 25 years but long life in the wild is rare for they have many enemies: lizards, snakes, spider-eating birds and the deadly tarantula hawk. This large metallic blue, green and red wasp is the spider's fiercest and most dreaded enemy. Once it has found and paralyzed the spider with its poisonous sting, the wasp drags its victim to a prepared burrow, deposits its eggs in the spider's abdomen and seals its victim in. Upon hatch­ing, the wasp larvae feed on the tarantula's body.

Although the tarantula is frightening in appearance, the chances of being bitten by it are rare, and, because it has a rightful place in the outdoors, it should not be wantonly killed or persecuted. If its presence is not desired, it can be easily placed in a container and transported to some area where it can continue, unmolested, to live its useful life.

This article is one of a series published by the California Department of Fish and Game. Single-sheet reprints are available to California residents from Department of Fish and Game offices. Bulk quantities (minimum number: 25 copies) may be purchased only from the Publications Sec­tion, Department of General Services, P.O. Box 1015, North Highlands, CA 95660, for $.04 each (includes state sales tax).