Scorpions: friend or foe? Do scorpions deserve their bad reputation? One scientist finds out.
Scorpions are found on every continent except Antarctica, although desert habitats hold the greatest diversity. "The places where scorpions can be found tend to be very harsh environments," says Prendini, a scientist at the American Museum of Natural History in New York. Risks like exposure to dangerous tropical diseases, deadly snakes, and ovenlike heat are all part of the job, he says. Prendini has braved them all on the way to discovering more than 70 new species of scorpions.
Scorpions are relatives of spiders. These eight-legged arachnids have lobster-like pincers and their bodies can grow up to 20 centimeters (8 inches) long.
Unlike most invertebrates, female scorpions give birth to live young and are nurturing mothers. "We found a scorpion in Mexico that arranges the babies on her back and transports them around, like passengers on a bus," says Prendini. Some scorpions even feed and care for their young for up to two years.
Scorpions, however, are probably best known not for their motherly love, but for their frightening tails--which are topped with venomous stingers. By injecting venom into its victim, the scorpion can catch a meal or defend itself if it feels threatened.
Each scorpion species has its own unique venom made up of a complex mixture of chemicals. Most scorpion venoms are harmless to people. Out of 1,500 known species of scorpions, only about 25 are dangerous, says Prendini. "Healthy adults would probably survive scorpion stings by even the most venomous species," he says. Still, 800 people die worldwide each year from scorpion stings. Children and the elderly are most at risk.
Some scorpion venoms can actually be beneficial to humans. Scientists recently found one type that can be used to treat brain cancer. When administered properly, certain chemicals in the scorpion venom kill cancer cells, but leave a person's healthy cells unharmed.
The search for medicinal uses of scorpion venom has just begun. "I have no doubt that as we learn more about scorpion venoms we will discover more uses," Prendini says.
Another reason Prendini studies scorpions is that the creatures hold clues about the environment around them. Scorpions stick close to the specific habitat they're adapted to. By studying DNA and the physical characteristics of various scorpion species that have lived in a region over thousands of years, Prendini hopes he'll be able to determine how the world's ecosystems have changed over time.
Plus, scorpions are very sensitive to environmental changes. Prendini can judge the state of an ecosystem by looking at scorpion populations. If scorpions are sick or dying off, the ecosystem is probably in trouble.
In many areas, human activities like agriculture and mining have negatively altered scorpions' habitat. As a result, several scorpion species are endangered. That's a sign that many other plant and animal species are likely facing environmental pressures and are at risk of dying off too.
"Fewer than half of all the world's species are known to science and we're destroying their habitats faster than we discover them," says Prendini. For both humans and scorpions, the stakes are high.
We stand to gain so much from studying species--even ones with bad reputations, like the scorpion, says Prendini.
check it out
Scorpions have been around a long time--400 million years, by some estimates. They belong to a group of animals known as the chelicerates that includes water-dwelling horseshoe crabs as well as spiders, mites, and ticks. You can check out how all living things are related at the American Museum of Natural History's Spectrum of Life exhibit in the Hall of Biodiversity. To learn more, ask your teacher, or visit www.amnh.org. You can also visit http://ology.amnh.org.
SCORPION SCIENTIST: Lorenzo Prendini, a scientist at the American Museum of Natural History, enjoys studying scorpions for many reasons. Of particular interest to him is the medicinal value of the venom that the arachnids release from their stingers.
Don't forget to take part in the Kids' Environmental Report Card, presented by Science Explorations: www.scholastic.com/reportcard
DID YOU KNOW?
* To survey for scorpions in the dark, use a portable black light. Scorpions glow brightly trader black light.
* Scorpions have 6 to 12 eyes. Despite having so many eyes, their vision is poor. They navigate by using sensory hairs on their bodies that pick up vibrations and scents.
* Why are scorpions so sensitive to environmental changes?
ART: Do research on the constellation Scorpius. Then make a drawing of the constellation and label its main stars.
* This University of California Web site features a thorough description of scorpions: www.ipm.ucdavis.edu/PMG/PESTNOTES/pn74110.html
* Learn more about Lorenzo Prendini's research by visiting: http://scorpion.amnh.org/index.html
DIRECTIONS: Rewrite the false statements below to make them true.
1. Scorpions are six-legged insects.
2. Like most vertebrates, scorpions lay masses of eggs and do not care for their young.
3. Venom is made of saliva.
4. Scorpions inject venom with fangs. Their venom is always deadly to people.
5. Scientists have found that one type of scorpion venom can be used to treat stomach aches because it kills all the bacteria in the gut.
1. Scorpions are eight legged arachnids. They are relatives of spiders.
2. Unlike most invertebrates, scorpions give birth to live young. Some scorpions feed and care for their young for up to two years.
3. Venom is made of a complex mixture of chemicals.
4. Scorpions inject venom with their tail. Most scorpion venoms are harmless to people Healthy adults would probably survive scorpion stings by even the most venomous species.
5. Scientists have found that one type of scorpion venom can be used to treat brain cancer. When administered properly, certain chemicals in the scorpion venom kill cancer cells, but leave a person's healthy cells unharmed.
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|Title Annotation:||LIFE: INVERTEBRATES|
|Date:||Jan 14, 2008|
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