TARANTULAS
Tarantulas are big, hairy spiders whose name comes from the Italian town of Taranto, the home of a cult that worshiped wolf spiders and held wild Dionysian rites that reportedly began after revelers went into spasmatic dance after being bitten by spiders. The people of Taranto still perform a spider dance today. [Source: Richard Conniff, National Geographic, September, 1996; Samuel D. Marshall, Natural History, September 1992; Sy Montgomery, Discover magazine, February 2004]
Tarantulas arose around 150 million years age from smaller, hairy spiders. Like their modern descendants ancient tarantulas had fangs that moved up and down rather sideways as is usually the case with other spiders and they didn’t weave webs.
Tarantulas come in a wide range of exotic colors, including pink, purple and red. Most have broken and black colorations that help them blend into their habitat of trees, leaves or soil. They are found all over the world, in every continent except Antarctica. About 500 of the 850 or so known tarantula species are found in the Americas, particularly in the Amazon rain forests. Asian and African tarantulas are said to be more aggressive than their counterparts in the Americas.
Interesting species include the dangerous silver and black “Heteroscodra maculata” from Cameroon; the iridescent “Avicularia metallica” from French Guiana and Tanzanian chestnut tarantulas, Mexican blonde tarantulas, African baboon spiders, Cameroon red tarantulas and Indian ornamental tarantulas, with bright yellow-and-black markings on their forelegs.
Book: “Tarantulas and Other Arachnids: A Complete Pet Owner’s Guide” by Samuel Marshall, the son of actor E.G. Marshall and as of 2004 was working out of lab at Hiram College near Cleveland.
Websites and Resources: Tarantulas.com tarantulas.com ; National Geographic National Geographic ; Amazing Tarantulas amazingtarantulas.com ; American Tarantula Society atshq.org ; Wikipedia article Wikipedia ; Tarantula Guide tarantulaguide.com ; Tarantula Breeding spidy.goliathus.com ;
Websites and Resources on Insects: Insect.org insects.org ; Insect Images.org insectimages.org ; BBC Insects bbc.co.uk/nature/life/Insect ; Insect and Arachnid entomology.umn.edu/cues/4015/morpology ; Wikipedia article Wikipedia ; Virtual Insect home.comcast.net ; National Geographic on Bugs National Geographic ; Smithsonian bug info si.edu/Encyclopedia_SI/nmnh/buginfo ; Entomology for Beginners bijlmakers.com/entomology/begin ; BugGuide bugguide.net ;
Websites and Resources on Animals: ARKive arkive.org Animal Info animalinfo.org ; Animal Picture Archives (do a Search for the Animal Species You Want) animalpicturesarchive ; BBC Animals Finder bbc.co.uk/nature/animals ; Animal Diversity Web animaldiversity.ummz.umich.edu ; International Field Guides media.library.uiuc.edu ; animals.com animals.com/tags/animals-z ; Encyclopedia of Life eol.org ; World Wildlife Fund (WWF) worldwildlife.org ; National Geographic National Geographic ; Animal Planet animal.discovery.com ; Wikipedia article on Animals Wikipedia ; Animals.com animals.com ; Endangered Animals iucnredlist.org ; Endangered Species Resource List ucblibraries.colorado.edu ; Biodiversity Heritage Library biodiversitylibrary.org
Tarantula Characteristics
Tarantulas are distinguished from wolf spiders by the spokelike grooves in their carapaces. They have four lungs and jaws, and don't build webs like most other spiders. Many tarantula species take eight to ten years to mature and some live to be thirty years old. They belong to a different family of spiders than other kinds of spiders.
Giant bird-eating tarantulas from Venezuela weigh a quarter of a pound. Like all spiders, tarantulas have no internal skeleton. About once a year they emerge from their rigid skin, an effort that takes several hours and resembles trying to squeezes out of a tight-fitting glove.
Tarantulas have hundreds of tiny bristlelike hairs and needle sharp retractable claws at the bottom of their feet that allow them cling to glass and steel by squeezing into microscopic surface cracks. Some species have pontoon-like pads of hair that allow the relatively lightweight spiders to skitter across pools of water.
Almost all species of spider are hairy, but their hair is not like human hair. Spider hair is actually part of the spider's body — extensions of the exoskeleton call senate. Some of the follicles are actually sense organs for touching, tasting, hearing, and are used for detecting prey or mates. Tarantula hair feels like velvety fur.
Tarantula Venom and Toxic Hair
Like nearly all spiders, tarantulas are venomous. The most potent venoms maybe are strong enough to kill a mouse. Most tarantula venoms are only strong enough to paralyze an insect. A compound called SNX-482 from the venom of the Cameroon red tarantula shows promise in treating neurological disorders.
Most tarantulas have venomous hollow fangs at the end of mouth parts known as chelicerae, located at the front of their carapace. Unlike other spiders that bite with with a pinching movements, tarantulas bite straight down which allows them to kill larger prey.
Not all tarantulas give off venom by biting their victims, Many inject toxins with hairs. Some species don't have stinging hairs (but these tend to bite) and other give off venom that is toxic to rodent but not to humans.
Tarantulas have the unique distinction of being the only spider with stinging hairs. Many species can fling poisonous hairs when annoyed. Other inject them by brushing their abdomens lazily against a victims hand. Sometimes the hairs are designed to defend against single species. Mexican blonde tarantulas, a species found in Arizona, have hairs specially designed for grasping and irritating the nasal passages of grasshopper mice, which like to feed on feed on them.
Although many species of plant have sharp barbs and stinging nettles, tarantulas, and a few species of moth, are the only animals know to be able to do this. The Urticating hairs — those that evoke stinging or itching — have evolved only in New World tarantulas. About 460 of the 500 species that live in the Americas have those hairs. As of the mid 2000s, seven different types of these hairs had been recognized. Some tarantulas shoot them from their mouths. Others shed them from the belies. One sheds them onto eggs sack to protect them from predators and parasites.
Hissing Tarantulas and Injecting Toxic Hairs
Animals that prey on prey on tarantulas include storks, owls, lizards, snakes and mammals such peccaries and coatimundis that root through the soil for food. Some tarantulas hiss to the warn predators off and hurl stinging hairs when threatened.
The poisonous hairs are released by some species when the spiders rub their legs along their abdomen. Humans that have been sprayed by tarantulas say the hairs spread out over a large area like pellets from a shotgun. Areas of exposed skin that were hit burned, followed by an itching sensation that persisted for several days. Animals are sometimes struck in the eyes, enduring agonizing itching that can last for months.
Some species of tarantula, especially the giant ones in Venezuela and French Guiana, rear up and produce a loud hissing noise when threatened, and then eject a cloud of poisonous hairs from their hind legs.
Hissing tarantulas generally make their noise by rubbing their legs together. The giants tarantulas of Venezuela however produce their sound by rubbing their front legs against small appendages next to their mouth. To prove that the tarantulas indeed make sound this way, scientists shaved their legs, and yes indeed, they couldn't make any noise.
Tarantula Kills
Tarantulas usually feed on insects or small amphibians. Some desert species occasionally feed on mice or rattlesnakes and some tree species have been observed eating small birds, bats and one of the deadliest South American snakes, the fer-de-lance.
Tarantulas first impale their victims with their sharp mandibles, then they eject venom, and finally an enzyme is applied to soften the meal so it can be consumed as a liquid. Describing the capture of a three-inch giant cockroach by a tarantula, Richard Coniff wrote in National Geographic , "The tarantula stepped out from its burrow, then lifted two front legs to touch the cockroach gently, almost affectionately...Then in a blur, the spider latched its feet onto the roach's far side, flipped it on its back, and planted its fangs in relatively soft membrane of the underside, near the head. It dragged its victim into the burrow. The roach twitched briefly, then went still. The spiders fangs continued to rise and fall, pumping venom. We could hear the spider's fangs and serrated teeth begin to click like lobster picks.”
Like other kinds of spiders, tarantulas can not eat solid food. They digest their food externally by vomiting digestive juices onto their prey and then using a strawlike appendage to suck up the liquified food. Spiders don't to eat all that often. Tarantulas can live as long as year with out food. Describing a tarantula consuming a small bat, tarantula expert Rick West told National Geographic. "As the tissues dissolve, the limbs will come apart. At the end of the night the only thing left will be the wings, the bones and some hair in a big pellet mixed with silk."
There is one Australian species that produced a venom that is not that harmful to humans but is deadly to dogs. There are stories of this species rearing up on its hind legs and waving its legs and gnashing its fangs and chasing dogs away. There are also reports of Old World tarantulas rearing and chasing dogs that have disturbed them.
Tarantula Homes
Most species of tarantula live in burrows in the ground. Sometimes they are concealed with leaves or have a lid or a trap door made of earth held in place by thread. Often located by scientists by the presence of small mounds of desiccated insect parts, they are generally a foot or so deep and are dug by tarantulas using only their mouth parts. Tarantula burrows are often found in groups.
Tarantulas don't make webs but many make silken homes in their burrows. Some live in silken sheets they produces in trees. Generally benign enough be handled by humans, these spiders sometimes make their homes in the eaves of houses and under banana trees and pineapple plants.
Most species of tarantula prefer to stay near their homes. Many kinds refuse to venture further than a few centimeters from their burrows their entire lives. The spiders generally wait for their prey to come to them. Some string strands of silk in front of their homes to help them detect prey. On species from Southeast Asia is named the tiger tarantula because of the speed it burst from its burrow to seize prey.
Tarantula Behavior
"Tarantulas are kind of boring,” West told National Geographic. "They're sit-and-wait predators. They don't do much." Most species sleep all day and emerge from their burrows at night and wait prey to wander in their direction. Tarantulas can be very fragile and easily stressed out. When held in captivity, some spiders become nervous and go "bald" from shedding hairs on their abdomen.
Tarantulas tend to be grumpy loners, in some cases so intolerant of other spiders that females sometimes eat potential suitors. But this is no the case with all species. A female African baboon spider did not try to eat a male suitor even when it stayed in her cage for two months. Another female of same species did nothing when the offspring from different female annoying crawled all over her and tried to eat her food. Studies by Marshall’s undergraduate students Melissa Varrechia and Barbara Vasquez have found that Indian ornamental tarantulas prefer living with a sibling.
But behavior varies quite a lot. Some mothers tenderly care for their young. Female Tanzanian chestnut tarantulas give food to their offspring and grow thin themselves so their babies will prosper and thrive. Some tarantula families share food. Young of the Cameroon red tarantula feed side by side with their legs interlocked together. Marshall, who wrote about this behavior in a paper, told Discover magazine. “They huddle feeding together. This is cooperation.”
Marshall told Discover magazine there is also a lot of individualism among tarantulas, Marshal told Discover, “I’ve brought a lot of “Theraohosa” out [of the jungle] and into captivity. Some would settle down and adapt to the artificial habitat of their terrarium with a cave I provided, while other would pace and pace. It’s very clear to me that individual spiders can differ in how they respond to stimuli.” There have been reports of tarantulas sporting multi-colored stones and families that learned to unscrew the lid to the jars they were held captive in and stories about individuals of the same species being both easy to handle and freaked out by the slightest contact with humans.
Mating Tarantulas
During the mating season female tarantulas often hole up in their burrows with 75 to 2,000 unfertilized eggs while males wander about, sometimes attracted by an alluring pheronomes emitted by the female. Before mating males weave a web, deposit some sperm on the web and then draw the sperm to the bulb-shaped tips of the leg-like appendages near their mouth.
Describing a pair of mating tarantulas, Richard Conniff wrote in National Geographic, "Gingerly their front legs touched; then she sidestepped and he followed. With his pedipalpi, the leglike appendages at his front end, he beat a tattoo on the ground, a declaration of interest. He began to caress her, drumming his pedipalpi on her carapace. Gradually face-to-face, they entwined their front limbs together like the fingers of two hands in velvet gloves."
"They pushed one another up in the reared-back position of both love and war," Coniff wrote. "The male hooked his front legs over her fangs, and with his second set of legs bent her backward. Then he reached under to transfer the sperm from his pedipalps to the epigastric furrow at her midsection. The dance ended with the male scrambling safely out of reach. In moments of postcoital “tristesse”, a female will sometimes kill the male, a handy source of protein for her newly fertilized eggs."
Tarantula females handle their eggs sacs by holding them in their mouth. Some species tenderly take care of their young with some mothers going without eating so there is more food for her offspring. Captive breeding with tarantulas is slow.
A small inch-long tarantula species perform an elaborate dance in which both the male and female participate, the male twitches and drums his legs and the female responds by gracefully fanning her legs. The dance continues for several minutes before ending in copulation.
Tarantulas and Wasps
Several species of wasp paralyze tarantulas with their sting and then lay eggs in spider’s abdomen. When the eggs hatch the paralyzed spider is eaten alive by wasp larvae, Even the goliath bird-eating spider is not immune. It is preyed on by a species of wasp the size of a sparrow.
Some tarantulas are preyed on by wasps that are so big they are called tarantula hawks. According to a caption at a spider exhibit in Washington D.C., "The female wasp stings a tarantula to paralyze it, then drags the heavy victim back to her burrow, lays an egg on the spider's abdomen and closes the burrow. The paralyzed prisoner is eaten alive by the grub when it hatches."
Tarantulas are also attacked by species of wasp one tenth their large. After a brief tussle the wasp lands on the spider's abdomen and discharges a tranquilizing chemical into the spider's leg with its stinger. After the tarantula is unconscious the wasp pulls it back to its burrow, drags it down the hole and lays it eggs on it. The spider is then buried alive. A few later when the eggs hatch, and the larvae feed on the spider.
Tarantulas and Humans
The fact that some spider venom is harmful to humans is a coincidence. Tarantulas are shy, virtual harmless recluses. Usually when handled they don't bite. Most tarantula bites are no worse than a wasp sting. No tarantula produces a strong enough venom to harm, let alone, kill a human. There is not a single report of a human dying from a tarantula bite. They are much less dangerous than black widows or redback spiders in Australia. One scientist, who had been bitten by a dozen different tarantula species said, "I'm still her and in moderately good health.”
Tarantula's undeserved reputation as killers comes partly from the tales of adventurers like P.H. "Exploration" Fawcett who described a huge black tarantula in Peru that "lowered itself down at night on the sleeper beneath, and its bite meant death." In Central America some tarantulas were referred to as horse spiders because it was believed that their bite could cause the hooves of horses to fall off.
Tarantulas have also gotten a bad rap in films. The 1955 film “Tarantula” featured hundred-foot-tall beasts that ate cattle and crushed houses and were "more terrifying than any known horror to man." The desert town menaced by the spiders was eventually rescued by an air force pilot played by Clint Eastwood who drops napalm on them. The 1957 film “The Incredible Shrinking Man” features hairy spiders referred to as "every unknown terror in the we world, every dear fear fused into one hideous night black horror."
Some people keep tarantulas as pets. Mexican red knee tarantulas are very popular. The sell for around $150 a piece. Threatened in the wild, these spiders are now protected.
Eating Goliath Bird-Eating Spider and Hunting Tarantulas in Peru
The giant Goliath bird-eating spider of Central Venezuela is a species of tarantula large enough to span a ten inch dinner plate. The largest arachnid on earth, it is hairy and has fangs almost an inch long. Describing one he saw in 1535, the Spanish explorer Frenández de Oviedo wrote, "There are spiders of marvelous bigness...bigger than a man's hand."
These giant spiders are feasted on by Piaroa Indians who consider them a delicacy. Before the hunt a hunt a shaman in a headdress adorned with a beeswax replica of a tarantula invokes the blessing of spirits. By twitching a vine in the tarantula's burrow, imitating the movement of an insect, hunter lures the ground dwelling spiders from their lair. When one emerges the hunter pins it to the ground with two fingers and, carefully gathering up its eight legs, and tucks the spider into a bundle of leaves. The spiders are kept alive until just before cooking. Once the barbed hairs are singed off, the legs and thorax are barbecued. They taste much like shrimp. The Piaroa use the spider's fangs as toothpicks. [National Geographic, March 1992].
Describing a Peruvian tarantula hunter in action, Conniff wrote. "In one hand he balanced a machete by the blade. In the other he carried a stick with a sharpened ice pick at one end. It took him about ten minutes to excavate the first tarantula burrow, hacking out the clay with angled slices. When the tarantula was finally cornered at the bottom, it made a desperate lunge, and Nilo gigged it through the carapace. He held the tarantula up for display, and it wriggled on the spear point, its milky blue blood leaking from the wound. He would sell it in the city for about a dollar, with fifty or a hundred other tarantulas killed in the some way in preserved in alcohol."
Image Sources:
Text Sources: Mostly National Geographic articles. Also “Life on Earth” by David Attenborough (Princeton University Press), New York Times, Washington Post, Los Angeles Times, Smithsonian magazine, Natural History magazine, Discover magazine, Times of London, The New Yorker, Time, Newsweek, Reuters, AP, AFP, Lonely Planet Guides, Compton’s Encyclopedia and various books and other publications.
Last updated March 2011