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Tarantulas

General Info

About 900 species of tarantulas live throughout the world. Those found in North America thrive in the southern and southwestern states, including the dry and warmer parts of southern California. These are smaller than other varieties, and generally have a body length of less than 2", with a leg span of 3 - 4". Many tarantulas can live between 24 and 40 years.

The majority of tarantulas are black or brown, but some species exhibit striking colors. The Mexican Red-legged Tarantula (Brachypelma smithi) has bright-red leg markings, while the Cobalt Blue Tarantula (Haplopelma lividum) has legs that are deep blue. The Rose-Haired Tarantula (Grammostola rosea) and Chilean Copper Tarantula (Paraphysa scrofa) are also beautiful, mild-tempered arachnids.

The tarantula family includes the largest spiders known. The Goliath Tarantula (Theraposa leblondi) which inhabits South America, reaches a body length of 5", with a leg span of up to 12". Even the small tarantulas reach a relatively large body length of 1½". Certain South American tarantulas, which have a body length of up to almost 3", build large webs and eat small birds.

The Desert Tarantula (Aphonopelma chalcodes) grows 2 - 3" long, and is colored gray to dark brown. It is common to the Sonoran, Chihuahuan, and Mohave deserts of Arizona, New Mexico, and southern California. The most common North American tarantula is Eurypelma californicum, found in California, Texas, and Arizona.

A conspicuous bald spot seen on the abdomen of many tarantulas results from the spider's defensive behavior against its vertebrate enemies. When confronted, the spider will rub its hind legs over its body, brushing off annoying "urticating" hairs into an enemy's eyes. These hairs are replaced during each successive molt.

The tarantula's cephalothorax and abdomen, the front and rear parts of the body, are round. Its eight eyes are closely grouped, with a pair in the middle and three on each side of the face. It has large fangs, and two pairs of slits on the underside of the abdomen that lead to the respiratory organs, called "book lungs." Book lungs have many folds lying close together, like the pages of a book, through which blood passes to acquire oxygen from the outside air.

Most tarantulas pursue and catch their prey (crickets, moths, and other insects) rather than building webs. Many also produce a hissing sound by rubbing their jaws, front legs, or palps (arm-like appendages between the mouth and legs) against each other.

Despite all the B-rated horror flicks you may have seen, tarantulas are completely harmless to humans, and can easily be trained as pets. They will only bite if provoked, and their bite is not considered poisonous. The venom injected into a human causes only slight swelling, with some possible numbness and itching which disappears in a short time. Skin exposure to the urticating hairs will cause itching and a rash.

First Aid: Clean the bite site with soap and water, and protect against infection. Skin exposures to the urticating hairs are managed by removing the hairs with tape.

Habitat

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, she hides inside cracked logs, and under any loose-lying debris.

Tarantulas are sluggish during the day, and spend most of their time hidden in burrows or other retreats. In the spring through fall, they become active in the late afternoon. Some dig their own burrows, while others use ready-made crevices or abandoned rodent holes. Others make their homes under rocks or logs, or under the bark of trees. They are not gregarious, meaning there is only one spider per burrow.

While North American tarantulas are exclusively ground-dwellers, living in burrows, others build silken retreats on trees, cliff faces, the walls of buildings, or in crop plants such as bananas and pineapples.

Food & Hunting

The tarantula is a nocturnal hunter. With very few exceptions (noted above), it does not spin a web to capture its prey, but catches its food by speed. It will take virtually anything of the right size that moves within its range, but feeds primarily on small insects like crickets, grasshoppers, beetles, sow bugs, other small spiders, and sometimes small lizards.

The tarantula strikes with its fangs, injecting a tiny amount of venom and grasping the prey with its palps. Then the tarantula grinds its victim into a ball, secretes digestive juices onto it, and sucks up the liquefied prey. It may also wrap the ball in silk for a later meal.

Breeding

Tarantulas do not reach sexual maturity for several years. During this time, they undergo a series of molts, and until they reach maturity it is virtually impossible to tell a male from a 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.

In the fall, males locate a receptive female by the scent she leaves on the silk of her burrow. After performing a courtship dance, the two spiders mate. Males usually die a few months after mating, but females may live and produce eggs for 25 years or more. Males may die a natural death or be eaten by the female, sometimes even before mating can occur.

Once mated, female tarantulas store sperm in special organs known as seminal receptacles. Immediately before fertilization and egg laying begins, she partially constructs a cocoon within her burrow. With the silken foundation laid, the female then releases a mixture of eggs and sperm through her genital opening into the cocoon. Once the eggs are deposited, she finishes sealing up the cocoon with silk, then stands guard until the 500 to 1,000 young hatch. Young tarantulas emerge from their cocoon 6 to 9 weeks after fertilization, then venture off on their own in another 2 to 3 weeks.

Conservation

Tarantulas have many natural enemies, including lizards, snakes, spider-eating birds, and the Tarantula Hawk. The large metallic blue, green, and red wasp is the Tarantula’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 another area where it can continue, unmolested, to live its useful life.

Giant Bird-Eating Tarantula
Colorful tarantula walking on wood floor
Tarantula
Tarantula walking across small pebbles
Tarantula
Giant goliath bird-eating tarantula Los Marmelos Tarantula standing on pine needles
Los Marmelos Tarantula
Colorful rose-hair tarantula standing on finely mulched substrate
Rose-Hair Tarantula