Species: 1,400 have been classified, but there may be as many as 2,000 species. Over 40 species can be found in the United States
Body length: longest— flat rock scorpion Hadogenes troglodytes, up to 8.2 inches (21 centimeters); smallest— Middle Eastern scorpion Microbuthus pusillus, 0.25 inches (6.5millimeters)
Weight: heaviest— emperor scorpion Pandinus imperator, up to 2 ounces (60 grams)
Life span: 5 to 15 years, depending on species
Gestation: Several months to a year, depending on environmental conditions
Number of young at birth: 1 to 95 over a period of several weeks, depending on species
Age of maturity: 6 months to 7 years, depending on species
Conservation status: many species are threatened by habitat loss.
• Scorpions can easily be seen at night with an ultraviolet
light due to a fluorescent material found in their hard outer
covering, which gives a "glow in the dark" appearance.
• Much like crickets, some scorpion species “sing” by rubbing their legs together. However, unlike crickets, it is thought that the song is used as a warning call instead of a call to attract a mate.
• A scorpion's first sting is made up of different toxins than later stings. The first is usually strong enough to stun a vertebrate prey or predator; later stings are usually milder or used on invertebrates.
• In high temperatures, scorpions may stilt, or raise their body off the ground, to cool off their underside.
• One species, the devil scorpion Tityus serrulatus from Brazil, reproduces by parthenogenesis, meaning the female doesn't need a male to fertilize her eggs.
Scorpions strike fear in many people and have been both hated and admired since ancient times. This is probably due to their fearsome look, with pincers at one end and a stinger at the other. Scorpions are not insects but are arachnids, like spiders, and have eight legs and two main body regions, the prosoma and the mesosoma. The prosoma has two eyes on top and two to five eyes along each side (as many as five pairs). Even with all those eyes, scorpions can't see very well! Their eyes mostly tell movement and light from dark. The scorpion's four pairs of legs are attached to the prosoma as well. Scorpions find their way by feeling along with brush-like structures called pectines attached to the underside of the mesosoma, and fine sensory hairs to detect vibrations. Male scorpions also use the pectines to find an available female. The scorpion's tail, called the metasoma, ends in a sharp stinger with venom glands.
First on land
Scorpions have been on Earth a long time and are among the first animals to have adapted to land—around 420 million years ago. There are fossil records from that time period of a marine scorpion that grew up to 3.3 feet (1 meter)! Today, scorpions use book lungs to breathe, a type of breathing organ also used by some spider species and very similar to gills.
Home, sweet home
Scorpions are nocturnal and solitary, usually staying in the same territory throughout their lives. Many species live in burrows that they dig or claim and defend from other animals. Scorpions use the burrows to stay cool during hot days and warm during cold nights. They like their burrows to be small and snug. Scorpion species that do not burrow may climb trees or hide under bark for shelter. In cities, scorpions have been known to seek shelter in houses, crawling into shoes and even beds!
A male may leave his home territory to seek out a female by searching for her scent. Mating rituals vary from species to species, but in general, if the female is interested, the male begins a courtship dance: he grasps the female's feet (pedipalps) and turns her in circles, moving her back and forth. The two will raise their stingers over their backs, sometimes touching them together. This dance may last from a few minutes to hours. The male feels the ground for a flat surface with his pectines to deposit his packet of sperm, called a spermatophore. He then brings the female over to the packet, which she pushes into her genital opening. Then the male will usually leave, because the overly aggressive female might decide he'd be a tasty snack!
Babies on board
Unlike most other invertebrates, female scorpions give birth to live young 2 to 18 months after mating, depending on the species. The babies look like miniature adults, except that they are usually very light in color (adults are dark), have no pedipalps, and cannot sting. The newborns immediately climb onto their mother's back, where they will remain for several days until their first molt. Some young will remain there much longer, depending on the species. She won't feed them, but she does carry them around and protect them until they are able to hunt and defend themselves. This is a tricky time for the young, however, because if the mother gets hungry, she will no longer recognize them as her young and may eat them! After that first molt, the young scorpions will leave to establish territories of their own and will be sexually mature after their sixth molt.
Scorpions use different ways to get a meal, which may be an insect, spider, or even a small mouse or lizard. Many species will wait by their burrow with pincers open and stinger raised until their prey wanders by. Others will stalk their prey, and some species may even dig pitfall traps in the sand for prey. Once the prey is within reach, it is grabbed with the pincers and crushed. Most scorpions will only use their venomous sting if needed, as it takes a lot of body energy to produce more venom. Younger and smaller scorpions may use their stinger more often than older and larger ones.
Scorpions have a very tiny mouth and can only suck up liquid, so prey that is caught is mashed up and injected with enzymes that dissolve the prey's insides, a process which may take up to an hour. Scorpions don't eat every day like we do, and they have been known to go without food for up to 12 months, as long as they have water. Usually, scorpions find a meal at least every two to three weeks and play an important role in their ecosystem by keeping the insect populations down.
It has been found that a single species of scorpion may have as many as 45 different toxins in its venom. Some toxins are more useful on insects, some on crustaceans, and some on vertebrates. Scorpions use their venom to subdue their prey and for protection. Their predators include centipedes, shrews, owls, bats, hornbills, and coyotes. Some animals, like meerkats and hedgehogs, are immune or resistant to their venom.
All scorpions have venom, but of the thousands of species, only about 50 are considered life threatening to humans, and only two of those are found in the United States. The sting of most species is enough to kill an insect or spider but is merely painful to humans, like a hornet's sting. Few stings are fatal, but allergic reactions can happen. A physician should treat scorpion stings to ensure the patient will recover safely.
Scorpions are numerous in many regions but are rarely seen due to their nocturnal and secretive nature. Even so, many cultures have myths involving scorpions and their powers. Some people believe that scorpions will commit suicide by stinging themselves when threatened by fire. However, this is not true, as they are immune to their own venom. In Africa, it is a widely held belief that a dead scorpion will attract all the other scorpions in the area. This is also not true, as scorpions usually prey on live animals and do not seek out their own species except to mate. In Egyptian mythology, the goddess Isis was linked with scorpions, as she was a symbol of a devoted mother, and scorpion mothers protect and carry their young on their backs.
Now that you know more about scorpions, we hope you'll remain cautious but not fearful of these interesting arachnids!