COMMON NAME: ScorpionsSCIENTIFIC NAME: ScorpionesTYPE: InvertebratesDIET: CarnivoreAVERAGE LIFE SPAN IN THE WILD: 3 to 8 yearsSIZE: 2.5 to 8.3 inches
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.
Scorpions strike terror in many people and have been both hated and admired since ancient times. This is probably due to their fearsome look, with pincers called pedipalps at one end and a stinger filled with venom at the other. Scorpions are not insects but arachnids, like spiders, and have eight legs and two main body regions, the prosoma, or cephalothorax, and the opisthosoma, or abdomen. The prosoma has two eyes on top and two to five lateral eyes along each side (as many as five pairs).
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.
