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Authors: David Quammen
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past all chance of taxonomic identificationâbut a reasonable bet makes it C. sculpturatus.
I also talked with Ed Abbey, whose credentials to speak in any matter of deserts or ornery critters are unequaled. Amazingly, Abbey has only been scorpion-stung once, and that time while sitting quietly on a couch in a trailer house, late one night about a dozen years ago. He was barefoot. He was reading Gravityâs Rainbow. He didnât notice the scorpion that had come crawling peacefully up. He lifted one foot and set it down again, whammo, but Ed was so engrossed in Pynchonâs novel that all he recalls is tromping the scorpion to death with his stung foot, then quickly fetching a bucket of ice water, jamming the foot into it, and continuing to read. Yes, his assailant seemed to have been that species they call the bark scorpion. Yes, he had some sharp pain at the site, definitely, but nothing much more. On the whole, says Ed, it wasnât nearly so traumatic as the time a tiny insect, species unidentified, crawled deep into his ear and refused to come out.
There are several morals to be drawn. First and most obviously, heavy reading causes scorpion sting. Second, a person is safer while remaining stationary than in making even the most innocent movementâand safer still if the person remains stationary somewhere outside the borders of Arizona. And a third point to note is that the obliviousness seems to be mutual: They donât see a human hand or foot coming, those bumbling scorpions, until itâs too late. Otherwise they would surely, like us, prefer to avoid the whole experience.
â¢Â   â¢Â   â¢
They donât see us coming because they donât see much of anything. Ironically, despite their superabundance of eyes, most scorpions seem to be almost hopelessly blind. Scientists who study scorpion biology generally mention this handicap (âTheeyes are too crude to be of much assistance. . . . The eyesight seems to be of secondary importance. . . . Scorpions have poor eyesightâ), which is so pronounced, evidently, that it has been a mystery how scorpions could ever find their way to a meal. Stumbling around blindly out there in the desert, bumping into rocks and each other and Doug Peacock, the poor things should have long since starved to death and lapsed into extinction. Just lately, though, the mystery seems to have been solved.
In a recent issue of Scientific American, Philip H. Brownell has presented impressive experimental evidence for a new theory of how scorpions perceive the presence of food or danger.
They see with their feet.
More precisely, they rely on pressure-sensing organs near the ends of each of their eight walking legs to detect subtle shock waves that propagate outward, even through sand, when another creature passes by on the desert floor. According to Brownell, the scorpion orients itself toward the focus of any such disturbance by gauging the minuscule differences in the times at which the shock wave reaches each of its eight spraddled legs. Spaced apart, those legs serve as stereoscopic receptors. Take away the sensory input from one or two pairs of legs, or from all four legs along one side of the body, and the scorpion becomes confused. Disoriented. Like a human with only one good ear, and therefore no sense of auditory directionâor with only one good eye, and therefore no sense of depth. Take away all the input from those leg organs, and the scorpion is functionally blind.
They see with their feet. No wonder they need all eight. Okay, this I can accept. But Iâm still uneasy about all those sparkling eyes, which seem to serve no purpose except sheer decorative vanity. They donât walk with them. They donât depend upon them for vision. Couldnât they be satisfied with just five or six?
TURNABOUT
The Well-Kept Secret of Carnivorous Plants
Plants that eat animals are looked at, by us
I also talked with Ed Abbey, whose credentials to speak in any matter of deserts or ornery critters are unequaled. Amazingly, Abbey has only been scorpion-stung once, and that time while sitting quietly on a couch in a trailer house, late one night about a dozen years ago. He was barefoot. He was reading Gravityâs Rainbow. He didnât notice the scorpion that had come crawling peacefully up. He lifted one foot and set it down again, whammo, but Ed was so engrossed in Pynchonâs novel that all he recalls is tromping the scorpion to death with his stung foot, then quickly fetching a bucket of ice water, jamming the foot into it, and continuing to read. Yes, his assailant seemed to have been that species they call the bark scorpion. Yes, he had some sharp pain at the site, definitely, but nothing much more. On the whole, says Ed, it wasnât nearly so traumatic as the time a tiny insect, species unidentified, crawled deep into his ear and refused to come out.
There are several morals to be drawn. First and most obviously, heavy reading causes scorpion sting. Second, a person is safer while remaining stationary than in making even the most innocent movementâand safer still if the person remains stationary somewhere outside the borders of Arizona. And a third point to note is that the obliviousness seems to be mutual: They donât see a human hand or foot coming, those bumbling scorpions, until itâs too late. Otherwise they would surely, like us, prefer to avoid the whole experience.
â¢Â   â¢Â   â¢
They donât see us coming because they donât see much of anything. Ironically, despite their superabundance of eyes, most scorpions seem to be almost hopelessly blind. Scientists who study scorpion biology generally mention this handicap (âTheeyes are too crude to be of much assistance. . . . The eyesight seems to be of secondary importance. . . . Scorpions have poor eyesightâ), which is so pronounced, evidently, that it has been a mystery how scorpions could ever find their way to a meal. Stumbling around blindly out there in the desert, bumping into rocks and each other and Doug Peacock, the poor things should have long since starved to death and lapsed into extinction. Just lately, though, the mystery seems to have been solved.
In a recent issue of Scientific American, Philip H. Brownell has presented impressive experimental evidence for a new theory of how scorpions perceive the presence of food or danger.
They see with their feet.
More precisely, they rely on pressure-sensing organs near the ends of each of their eight walking legs to detect subtle shock waves that propagate outward, even through sand, when another creature passes by on the desert floor. According to Brownell, the scorpion orients itself toward the focus of any such disturbance by gauging the minuscule differences in the times at which the shock wave reaches each of its eight spraddled legs. Spaced apart, those legs serve as stereoscopic receptors. Take away the sensory input from one or two pairs of legs, or from all four legs along one side of the body, and the scorpion becomes confused. Disoriented. Like a human with only one good ear, and therefore no sense of auditory directionâor with only one good eye, and therefore no sense of depth. Take away all the input from those leg organs, and the scorpion is functionally blind.
They see with their feet. No wonder they need all eight. Okay, this I can accept. But Iâm still uneasy about all those sparkling eyes, which seem to serve no purpose except sheer decorative vanity. They donât walk with them. They donât depend upon them for vision. Couldnât they be satisfied with just five or six?
TURNABOUT
The Well-Kept Secret of Carnivorous Plants
Plants that eat animals are looked at, by us
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