SCORPIONS
There about 1,500 different species of scorpion in nine families, ranging in size from three quarters of an inch to eight inches, with largest monsters coming from India and West Africa. One specimen found in India measured 11.5 inches; one from Sierra Leone measured 9.01 inches. Buthids are the most dangerous scorpions. They are relatively small in size but their venom is very potent. Larger species in the Scorpionid family look more menacing but generally carry venom that is considerably less toxic. [Sources: Venomous Animals of the World; John F. Ross, Smithsonian magazine; Paul Zahl, National Geographic, March 1968]
Scorpion are tough, little beasts. They can survive long period in temperatures below freezing and temperatures above 115̊F, withstand powerful doses of radiation and go years without food. Although most scorpion species live in deserts and tropical areas that is not they the only place they have been found. Some species live in the Pacific Northwest and Canada. Others are found in the Swiss Alps. And other still have been found under snow covered rocks at 14,000 feet in the Himalayas, in caves a half a mile below the earth's surface, in crevices of pineapples and even in the sea.
Websites and Resources on Scorpions : Scorpion Files ntnu.no/ub/scorpion-files ; Desert USA desertusa.com ; National Geographic National Geographic ; Scorpion pictures spidy.goliathus.com/english/gallery-scorpions ; Scorpion anatomy ntnu.no/ub/scorpion-files/scorpion_anatomy ; Wikipedia article Wikipedia ; Scorpion Pet Wikipedia care-sheet.com/index/Scorpion ;
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
Scorpion expert: Gary Polis, Vanderbilt University.
Scorpions, Centipedes and Spiders
Scorpions and spiders are members of the Arachnid class of animals. They have eight legs and a hard exoskeleton and molt like insects . Many species are carnivores that feed primarily on insects. Many produce poisons and have hair on their legs that can detect sounds, sensation, objects and even taste.
Members of the Arachnid class of animals emerged about 400 million years ago and are more closely related to horseshoe crabs than insects.
Insects, centipedes, millipedes, arachnids (including spiders and scorpions) and crustaceans belong to the phylum of arthropods. Arthropods account for three fourths of all known animals. All have exoskeletons made of chitin; a body divided into segments and protected by cuticle; jointed legs arranged in pairs; an open circulatory system with organs bathed in a liquid called hemolymph that is pumped around the body by the heart; and a nervous system comprised of paired nerve chords.
Insects have three pairs of legs, spiders and scorpions have four, crabs and shrimps have five and centipedes and millipedes have many.
Scorpions and History
Scorpion are the worlds's oldest surviving land animal. They evolved from meter-long, scorpion-like creatures that emerged from the sea 350 million years ago and have remained virtually unchanged for the last 100 million years (a 30 million specimen preserved in a piece of amber looks exactly like modern scorpions).
People have long been fascinated by scorpions — a Zodiac sign was named in honor of one — but not endeared by them. In the first century A.D., Pliny the Elder wrote: "They are a horrible plague, poisonous like snakes, except they inflict a worse torture by dispatching their victims with a lingering death lasting three days...Their tail is always engaged in striking and does not stop practicing at any moment, lest it should miss an opportunity.”
The Bible referred to scorpions as one of most evil pestilence and in Persian mythology, a scorpion played a role similar to that of the snake in the Garden of Eden, by sting the testicle of a sacred bull whose blood was to supposed to fertilize the universe.
Scorpion Characteristics and Behavior
Scorpions have eight legs and pinchers like crabs, called pedipalps. Their venom is released from a claw-like stinger on the creatures tail, which actually isn't a tail but an extension of its abdomen. Scorpions periodically molt their armorlike skin.
Scorpions have anywhere from two to 12 eyes yet are virtually blind. They can make out the difference between white and dark, but they can "see" an object. Their sense of touch is their most important and developed sense. Like spiders they have hair on the legs that can detect sounds, sensation, objects and even taste.
Scorpions give off natural fluorescence under ultra-violet light, This means they glow in the dark when exposed to a black light, which is how scientists often find them.
Scorpions usually only come out at night. Their days are spent under rocks or in cracks or in burrows. They seek out dark places which is why they sometimes into shoes. Some species spend 92 percent to 97 percent of their lives in corkscrew-shaped burrows.
Scorpions on the defense usually flick up their stingers and then make a quick dash for cover. Sometimes they rise on their legs and swivel like a tank turret and then quickly dig themselves into the sand. They often travel in pairs so if you find one scorpion there is probably another lurking around somewhere close.
Scorpion Feeding Behavior and Venom
Scorpion feed on worms, centipedes, grasshoppers, flies, beetles, cockroaches, crickets, moths, spiders, wasps and small lizards. Many species locate their prey by picking up their vibrations on the ground. The large scorpionids often dig to locate prey such as spiders, lizards and even small mammals.
Scorpions attempt to subdue their prey mechanically with their pincers, saving their stingers only for a last resort because it sometimes it a week or more to generate a new venom supply. Prey is eaten with pincer-like appendages near their mouth that break the prey into little pieces before inserting their mouth.
Scorpions in turn are fed on by lizards, birds, small mammals and even monkeys and baboons. Some species of owls sweep down out of the sky, bite off the scorpion's stinger and then consumes the rest of it.
Scorpions sometimes use their toxin to immobilize prey but it is primarily a means of defense. Venom is produced in a pair of venom glands that are located near the stinger at the end of the “tail.” Generally a scorpion stings its victim by arching the "tail" over the back of the abdomen and making the strike in front its body.
The levels of toxicity in the venom varies quite a bit. The most dangerous scorpions are found in Mexico, India, the Middle East and southern African countries such as Namibia. The most venomous scorpion is the Palestine yellow scorpion. Ranging across North Africa and the Middle East, it fortunately only delivers small amounts of poison.
Scorpion Mating
Scorpion males locate females by sweeping "toothed" leglike structures called pectines over the ground to detect pheromones given off by females that indicate when they are ready to mate. When males sense these pheromones they often start shaking wildly in a motion scientists have dubbed "juddering."
Like praying mantis and some spiders, female scorpions often kill the males after mating is over by injecting them with a series of lethal stings. In many cases the female will then devour the male. Even before mating begin, females sometimes view they male as prey. When a male approaches a female he does so with trepidation and often grabs her pincers before he does anything else.
During sex, the male and female jerk and dance around, sometimes with their tails intertwined, with the male holding the female in his pincers. The a male scorpion ejaculates on the ground and pulls the female so her sex organ touches the sperm. After she takes in the sperm the couple usually disengage and go their separate ways.
Describing the mating habits of scorpions, the famous 19th century French naturalist Jean Henri Fabre wrote: "One of either sex, face each other with claws outstretched and fingers clasped. Their tails prettily curled, the couple stroll with measured steps. The male is ahead and walks backwards; the female follows obediently, slashed by here finger tips and face to face with her leader. At times the male turns gracefully to right or left and places himself side by side with his companion. Then for a moment with his tail laid flat, he strokes her spine. She stands motionless, impassive."
Fabre wrote, "For over an hour I watch, and then something happens. The male has found a shelter to his liking. he releases his companion with one hand, and, continuing to hold her with the other he scratches out with legs and tail a shallow opening in the sand....He enters and slowly, without violence, drags partner after. A plug of sand closes the dwelling. The couple are at home."
Scorpion Offspring and Cannibalism
Scorpion eggs hatch in their mother's pouch and the young crawl out and climb on her back. Scorpion babies are soft and vulnerable and look like little potato bugs. They spend about two weeks on their mother's back, storing up food. After about a month they begin fending for themselves.
Scorpions often feast on other scorpions and eat their own mates and offspring. Biologist believed that scorpions developed this trait to survive under severe condition when they would most likely starve if they didn't eat other. They also say this trait has allowed scorpions to survive as long as they have.
Cannibalism among scorpions of the same species is so widespread that young scorpions often feed and move around at different times and in different places than their elders to avoid being eaten. Scorpions are particularly vulnerable to attacks after the molt and they lack the body armor to fend off attacks.
Scorpions and People
Scorpions like warm, dark places. Sometimes they hide in garages or piles of things or crawl into shoes, clothes or bed lining. They are hard to keep out of house. People who in live in places with scorpion are advised to wear shoes at all times, check their shoes and clothes before they put them on, and not blindly reach in dark spaces.
Scorpion researchers locate scorpions at night with black lights connected to motorcycle batteries stored in their backpacks. Half the known species of scorpion were discovered after scorpion's ability to fluoresce under ultra-violent light was discovered in the 1960s. Newcomers to this kind of search are often surprised by the number of scorpions that materialize in places where it seemed like there were no scorpions. First-rate scorpion collectors can snag 75 individuals an hour.
Scorpions are milked to make antivenin by squeezing the venom glands with tweezers and giving the scorpion an electric shock which causes the gland to contract and empty its venom.
The emperor scorpion is indigenous to West Africa. It is very large (up to 30 centimeters in length) and is less venomous than other scorpion species. It is a popular pet as it is also easy to raise, and sells for between $20 and $50 at pet shops.
Human Scorpion Victims
Some scorpion poisons are 100,000 more powerful than cyanide. What saves human victims is the dose of poison are relatively small and stings are often less severe than a bee sting. Symptoms from a scorpion sting include severe pain spreading from the wound, numbness, severe emotional agitation, cramps. Severe reactions include vomiting, diarrhea, respiratory failure.
Scorpion toxin is a powerful nerve poison, which explains why victim often feel like they have been jolted by an electric shock when they get stung. Often after the initial jolt a burning sensation spreads from the point of the sting, followed by numbness and tingling, which sometimes lasts for several days. Severe stings result in muscles cramps, convulsions, feeling of depression and deep anguish, excessive salivation, perspiration, bulging eyes, dramatic blood pressure rises, and increased and erratic heart beat. Death can occur in minutes or up to 30 hours later often from acute respiratory distress. In some causes the victim seems fine and then experience a violent relapse.
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Only 25 of the 1,500 species of scorpions deliver potentially lethal stings. Still, thousands of people are killed worldwide by scorpions, more than any other animals save snakes and bees. Most victims are children under five. Many deaths occur in India where 60 percent of the victims are killed by a particularly lethal species.
Describing a death from a scorpion sting, the zoologist J.L. Cloudsley-Thompson wrote, "First, a feeling of tightness develops in the throat so that the victim tries to clear his throat of an imaginary phlegm...The victims next becomes restless and there may be slight, involuntary twitching of the muscles...Convulsion follow, the arms are flailed about and the extremities become quite blue before death occurs."
If stung victims are advised to wash the wound with soap, place ice on it and take aspirin or acetaminophen. As is the case with poisonous snakes, wounds from highly toxic scorpions can be treated with antivenin.
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