Scorpion
Scorpions are members of the class Arachnida and are closely related to spiders, mites, and ticks. They are commonly thought of as desert dwellers, but they also live in Brazilian forests, British Columbia, North Carolina, and even the Himalayas. These hardy, adaptable arthropods have been around for hundreds of millions of years, and they are nothing if not survivors.
Hunting and Diet
There are almost 2,000 scorpion species, but only 30 or 40 have strong enough poison to kill a person. The many types of venom are effectively tailored to their users’ lifestyles, however, and are highly selected for effectiveness against that species’ chosen prey.
Scorpions typically eat insects, but their diet can be extremely variable—another key to their survival in so many harsh locales. When food is scarce, the scorpion has an amazing ability to slow its metabolism to as little as one-third the typical rate for arthropods. This technique enables some species to use little oxygen and live on as little as a single insect per year. Yet even with lowered metabolism, the scorpion has the ability to spring quickly to the hunt when the opportunity presents itself—a gift that many hibernating species lack.
Survival Skills
Such survival skills allow scorpions to live in some of the planet’s toughest environments. Researchers have even frozen scorpions overnight, only to put them in the sun the next day and watch them thaw out and walk away. But there is one thing scorpions have a difficult time living without—soil. They are burrowing animals, so in areas of permafrost or heavy grasses, where loose soil is not available, scorpions may not be able to survive.
HABITAT AND DIET
Scorpions are found on every continent except Antarctica, in habitats ranging from tropical rainforests to grasslands and deserts. As adults, most scorpions are nocturnal and solitary, usually staying in the same territory throughout their lives. Many live in burrows they dig or claim and defend from other wildlife. Scorpions use the burrows and other types of shelters to hide from predators and to stay cool during hot days and warm during cold nights. Their burrows are typically small and snug. Scorpions that do not burrow may climb trees or hide under bark or leaf litter for shelter.
Scorpions use different ways to get a meal, which may be an insect, spider, or even a small mouse or lizard. Many wait by their burrow with pedipalps open and stinger raised until their unsuspecting prey wanders by. Others forage for their prey, and some even dig pitfall traps in the sand for prey. Scorpions have such sensitive hairs on their pedipalps that they can even locate and snap up an insect in flight. Once the prey is within reach, it is grabbed with the pincers and crushed. Most scorpions use their venomous sting only 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 bathed in enzymes that dissolve the prey’s insides, a process that may take up to an hour. Scorpions don’t eat every day like we do, and in drier habitats, 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 insect populations low.
Scorpions may have as many as 45 different toxins in their 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 predators, like meerkats and mongooses, are immune or resistant to their venom.
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. All scorpions have venom, but of the 1,500 or so species, only about 25 are considered life threatening to humans, and only 2 of those are found in the US. The sting of most scorpions is enough to kill an insect or spider but is merely painful to humans, like a bee sting. Few stings are fatal, but allergic reactions can happen. A physician should treat scorpion stings to ensure the patient recovers safely.
FAMILY LIFE
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 pedipalps and turns her in circles, moving her back and forth. The two raise their metasomas over their back, sometimes touching them together, sometimes gently bumping each other without stinging in a behavior called clubbing. This dance may last from a few minutes to hours. The male feels the ground with his pectines for a flat surface 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. The male will then usually leave, because the overly aggressive female might decide he’d be a tasty snack!
One species, the devil scorpion from Brazil, is capable of reproducing by parthenogenesis, meaning the female doesn’t need a male to fertilize her eggs.
Unlike most other invertebrates, female scorpions give birth to live young 2 to 18 months after mating, depending on the species. The babies resemble miniature adults, except that they are usually white and soft bodied and cannot sting or feed. The newborns immediately climb onto their mother’s back, where they remain for several days until their first molt. During this time, they absorb a nutritious yolk sac and are fiercely guarded by their protective mother.
After their first molt, the young typically disperse. In some scorpions, the mothers kill a prey item and leave it for her babies, and in these scorpions the young (not surprisingly!) stay with Mom as long as two years. This is a tricky time for the young, however, because if the mother gets hungry, she may no longer recognize them as hers and might eat them! After that first molt, the young scorpions leave to establish territories of their own. The average time to maturity is between two and three years, with some species maturing in six months and some taking almost seven years!
