Spider myths and legends

Myth: Spider myths and legends.

Fact: The following myths, not heard as often as some others, have been sent in by correspondents since the first appearance of this site.

The myth that “there are tarantulas that can jump 3-4 feet” (1 meter) seems to be limited to the American southwest. No tarantula researcher has observed such an event. Any good-sized tarantula that fell that distance would likely be seriously injured. I had a Texan tarantula for 9 years in a 6 inch high terrarium and she never jumped out. Tarantulas can lunge 3-4 centimeters when capturing prey, but most of their movements are slow. One possible exception: juveniles of some South American tree-dwelling species, including the “pink toe” shown on this page, are reportedly able to jump moderate distances. But North American species are non-jumpers.

A correspondent had heard that “tarantulas crawl out of their skin before dying.” Like all other spiders, tarantulas do molt their “skin” a number of times while growing, but not just before dying, unless (as sometimes happens) they die of molt failure. A stranger myth about molting is that “the brown recluse is the only spider that sheds its skin.” Nope – they all do.

One occasionally hears a report of a ten-legged spider. One man wrote me that his son had heard about such a spider on a television documentary. Such reports involve certain spiders of the mygalomorph (tarantula-like) suborder that have unusually long pedipalps, which non-arachnologists can mistake for a fifth pair of legs. All spiders have palps (click here for a diagram of normal palps), but in the vast majority they are too small to be mistaken for legs.

A correspondent states that the saying “A spider by day is quite okay, but a spider at night should cause you flight” was common among early 20th century European immigrants to New York City.

Persons recovering from Latrodectus (black widow and related species) bites are sometimes told by well-meaning friends that if they are bitten again they will probably die! There is no medical basis for such a belief.

A Canadian correspondent has heard people say that stepping on a spider will bring some catastrophe like bad weather or a broken back.

A comment posted to an Australian web site states that the venom from a wolf spider bite “eats a centimetre of skin every month” and “in seven years … you could have no arm left.” Not only is this medically ridiculous, but no wolf spiders have been proven to have dangerous venom of any kind.

I’ve heard the “spider urine” myth once from the USA and twice from Latin America, where it probably originated. It seems that there are one or more spider species that urinate on sleeping persons, and the urine, rather than a bite, causes a skin ulceration. In Guatemala this myth centers on a tarantula species locally called araña de caballo (horse spider) which is said to cause severe hoof and leg trouble in horses and other livestock by urinating on them. In truth, spiders do not have separate urine and feces, and their droppings consist largely of guanine, which is a component of DNA and found in all living things; highly unlikely to cause any skin reaction!

One woman wrote of her husband’s belief that “all ‘sticky’ spider webs are from poisonous spiders.” Quite untrue – the most commonly encountered webs with sticky silk are made by orbweavers, none of which is medically significant.

Finally, a really strange one that probably derives from a garbled account of the life histories of some insect parasites: “From time to time, spiders breed by cloning. That is, the mother makes several clones of herself inside her body, and when the spiderlings grow they start to eat the mother until the mother is just an empty shell. You see this sometimes when you try to smash a spider and out of the smashed spider, hundreds of spiderlings creep out.” There is no real known case of anything resembling this.