Little Known Tarantula Traits

ByLee Dye

Jan. 4, 2001 -- Sam Marshall was a lad of 13 from the suburbs of New York City when he saw his first tarantula while on a family vacation in New Mexico. It was love at first sight.

Three decades later, he is possibly the world’s foremost authority on these hairy spiders that look far more menacing than they actually are. He has traveled the world in search of tarantulas, finding some that are so large they make the native tarantulas of the American southwest look like midgets, and he has established an extensive research program at Hiram College in Ohio.

But it all began with that family outing, and his first tarantula.

“It was one of the most amazing things I had ever seen,” he says.

Mythical, But Poorly Understood

By the time he turned 17 he had already accumulated a large collection of tarantulas, and they continued to fascinate him through high school and college. While working on his degree in biology, he set out to learn more about them. He says now he didn’t find much.

“Very little was known about them,” he says. “Practically nobody was studying them.”

Despite their somewhat awesome appearance, tarantulas seemed a bit dull to most spider specialists, he says. It didn’t seem like they did a whole lot, other than lurking in the dark of night while waiting for some unsuspecting prey to wander by.

So Marshall made it his obsession, and he has found that tarantulas are anything but dull. Maybe not as interesting as the myths that surrounds them, like they can jump great heights and race across a patio to bite you on the leg. They can’t do either.

The other myth that needs to be laid to rest is they can kill you with a poisonous bite.

“No tarantulas have ever been known to kill anybody,” he says. Some of them will bite if provoked, even the native species of the Southwest, but the wound generally feels like a bee sting and causes no lasting injury.

“It might be tender for awhile, but I don’t think it would be as dangerous as a cat bite,” Marshall says.

From Toxic Bites to Itchy Hair

But all tarantulas are not alike. Of the 80 different species he has in his lab at Hiram, some are so aggressive they will attack a plastic probe instantly, and some — from Africa and Asia — have a bite that is toxic enough to cause hospitalization.

But most just sit there, and Marshall says that in 30 years of collecting tarantulas he has never been bitten. But, he adds, “I’m very careful.”

Marshall’s research, including an unpleasant personal experience, shows that some tarantula species have a unique way of protecting themselves, and they don’t really need to bite in self-defense. Instead, they shed body hair.

“Many tarantulas can defend themselves with hairs they have on their body which are modified to act as irritants,” he says. “They can break them off by kicking them off the rear end of their abdomen, and the hairs float through the air. If you breathe them in, or get them in your eyes or between your fingers, they itch like crazy.”

Only the tarantulas found in North and South America are known to have that ability, he says, and it apparently has had a significant effect on their social habits.

“They tend to be extremely docile,” Marshall says, because they know they have that weapon if needed. “It’s very hard if not impossible to provoke them to bite.”

While he’s never been bitten, Marshall has had an occasional hair attack, and he says “it’s a sensation you don’t forget.”

The tarantulas found in the Southwest are big enough to strike terror in the heart of the mother of a teenage naturalist, but they are dinky compared to some found in South America.

Quarter-Pound Spiders

“The one I studied for my masters thesis is the largest in the world,” he says. He has captured some with a 10-inch leg span, and they tipped the scales at a quarter of a pound. There have been reports of some as large as 12 inches, he says, but he has never seen one quite that big.

Like their cousins to the north, these giant spiders can repel an adversary with “really ferocious hairs,” Marshall says.

Apparently, having that kind of equipment eliminates the need for a toxic bite, because their fangs are particularly benign. The most hyperactive tarantulas are in Africa. Marshall has some in his lab, and he says all you have to do is prod them with a plastic tube and “they rear up and begin attacking the tube almost right away.”

Another species from southeast Asia goes into some kind of a dance whenever it feels threatened.

“If provoked, it rocks back and forth,” he says. “That’s something none of the other spiders did.”It’s unclear at this point what all that means, he adds. “Maybe they’re just trying to look more dangerous, like ‘I’m ready to fight,’” he says.

If Looks Could Kill

North America’s tarantulas have a limited range. They do not occur naturally east of the Mississippi River, and are found no farther north than Missouri, Marshall says. They are not without enemies. A black and orange wasp, known in Arizona as a “tarantula hawk,” can paralyze a tarantula with its sting. Then it lays its egg on the spider, and when the young wasp hatches it burrows into the paralyzed tarantula and feeds on it.

It’s a jungle out there, and in many ways the tarantula seems poorly equipped to survive. It has a very primitive respiratory system, Marshall says, so if it tries to run away it won’t get very far until it runs out of breath and collapses.

It doesn’t have much of a bite, but it does have those obnoxious hairs.

And nature gave it one other defensive mechanism: An awesome appearance that would make just about anyone think twice before picking it up.

Lee Dye’s column appears weekly on A former science writer for the Los Angeles Times, he now lives in Juneau, Alaska.

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