Camel Spiders, Whip Scorpions, and Vinegaroons: Strange Arachnids
Unusual and Interesting Invertebrates
Camel spiders and whip scorpions are arachnids—invertebrates that have two body parts, eight legs, and simple eyes. Spiders, scorpions, tarantulas, harvestmen, ticks, and mites are also arachnids. Despite their names, a camel spider isn't a spider and a whip scorpion isn't a scorpion. Both animals are unusual creatures that are very interesting to observe.
Camel spiders live in deserts and get their name from their humped appearance. They are sometimes called wind scorpions, sun spiders, solifuges, or solpugids. Whip scorpions get their name from the whip-like extension at the end of their body. They are sometimes known as vinegaroons or vinegarroons because when they're alarmed they release a mist containing acetic acid. This chemical forms vinegar when it dissolves in water.
Arachnids are not insects. Unlike arachnids, insects have three body parts—head, thorax, and abdomen—three pairs of legs, and compound eyes.
The Camel Spider or Solifuge
Like other classes of living things, the class Arachnida is divided into different orders. Camel spiders belong to the order Solifugae. There are about a thousand species in this order. They live in dry areas of Africa, Asia, India, North America, and South America. They can be found in the southwestern part of the United States, where they are often known as wind scorpions instead of camel spiders.
Camel spiders are hairy creatures. Like other arachnids, they have four pairs of legs. They also have a long pair of front appendages called pedipalps which are sometimes mistaken for legs. The pedipalps are actually sense organs, although they sometimes help in locomotion. The front pair of legs may also act as sense organs in addition to being used for movement. There are adhesive structures at the tips of the pedipalps which enable some species of camel spiders to stick to vertical surfaces as they climb. The sticky structures may also be useful in catching prey.
Camel spiders have a large pair of chelicerae, which act as jaws. The animals also have structures known as racket organs or malleoli on the underside of their last pair of legs. The function of these organs is uncertain, but researchers suspect that they're used to detect vibrations in the environment.
Camel spiders aren't venomous and aren't particularly dangerous. They can give humans a painful bite, however.
The Lives of Camel Spiders
Hunting for Food
Camel spiders are generally nocturnal and are hunters. Small species feed on insects and other invertebrates. Larger species may add lizards and rodents to their diet. Many species of camel spiders have large chelicerae in relation to their body size. Each jaw has two segments with a joint between them. The segments bear tooth-like structures. The jaws are powerful and attack the prey's body very efficiently. Some species vibrate their chelicerae to produce a sound, as shown in the video above. This process is known as stridulation.
In those camel spiders whose mating rituals have been studied, the male begins the mating process by stimulating the female to enter a torpor. He does this by stroking her with his pedipalps or chelicerae. He then inserts sperm into the female's body. After the mating process has finished, the female digs a burrow in which to lay her eggs. In some species the female guards the eggs until they hatch.
Urban Legends About Camel Spiders
Camel spiders came to the general public's attention during the Gulf War and the war in Iraq, when American soldiers encountered them. Many urban legends developed about the arachnids during these periods. They were said to be giant animals the size of a man's calf—or larger—and to have a poisonous bite that was deadly to humans. They could supposedly run as fast as humans and were claimed to have a tremendous appetite, including a desire for eating human flesh. Rumor said that they attacked people with an anesthetic so that they could feast on their bodies while they slept. Camel spiders were also said to attack the bellies of camels.
The largest species of camel spiders that have been observed by scientists reach a head plus body length of about six inches. Most are smaller. Photos of giant camel spiders on the Internet are taken from a position that creates false perspective and makes the animals look large. The bite of a camel spider is not poisonous or deadly to human beings. It may be painful, however, and there is always a danger that the wound will become infected.
Camel spiders can move very quickly (relative to their size), but only for short periods of time. This rapid movement gives the animals their alternate name of wind scorpion. On a hot and sunny day the animals may sometimes appear to be chasing humans, but they are actually trying to hide in the shadows cast by people's bodies.
Whip Scorpions or Vinegaroons
Whip scorpions are arachnids that belong to the order Thelyphonida. They are small animals, although their legs may make them look larger. The bodies of most species are a little over an inch long. The largest species reach just over three inches in length. Like camel spiders, whip scorpions use three pairs of legs for walking. The front pair of legs are long, antennae-like structures that are used as sense organs. In front of these legs are the strong pedipalps, which have claws and act as pincers. The tip of the abdomen has an extension which bears the long tail. Unlike the tail of a true scorpion, the whip scorpion's tail doesn't have a stinger and is used to detect touch.
Whip scorpions are found in tropical and subtropical areas. They are nocturnal and carnivorous. They eat insects and invertebrates such as millipedes, worms, and even slugs, which they grab with their claws. They aren't venomous. When the animal feels threatened, it squirts a mist of acetic and octanoic acid (also known as caprylic acid) towards the eyes of its attacker from a gland near its tail. The smell of vinegar during this action gives the animal its alternate name. During the day the animal shelters in a burrow, which it digs under a structure such as a rock or a rotting log. It prefers dark and humid places for the burrow.
According to the University of Florida, vinegaroon spray consists of 85% acetic acid. In contrast, vinegar generally consists of around 5% acetic acid. The much higher concentration of the acid in the spray than in vinegar means we should be cautious when we are near a vinegaroon.
The Giant Vinegaroon
The giant whip scorpion (Mastigoproctus giganteus) is the species that is most often referred to as a vinegaroon. It's sometimes kept as a pet. (Yes, some people do keep invertebrates as pets.) It's the only whip scorpion that lives in the wild in the United States and is found in the southern part of the country. Although its appearance is dramatic, the animal is often a docile creature that walks calmly over people's hands. The claws can give a nasty pinch if the creature is alarmed or frightened, though. Its acidic spray irritates the skin of some people and could be dangerous if it enters the eyes.
Reproduction and Parental Care
During mating, a male giant vinegaroon inserts a packet of sperm called a spermatophore into the female's body. The female lays about thirty-five eggs in a burrow. The female lays her eggs several months after mating and holds the eggs in a sac under her abdomen while she's in her burrow.
After about two months the eggs hatch, producing young that are white in color. The youngsters climb on to the female's back and stay there for about a month. At the end of the month they molt, become dark in color, and leave the burrow. The female generally dies soon after. The male giant vinegaroon and the female if she doesn't reproduce have the potential to live for at least seven years.
If you're looking for an arachnid as a pet, don't get the terms whip scorpion and wind scorpion mixed up. The first animal is much more suitable as a pet than the second.
Whip Scorpions or Vinegaroons
Giant whip scorpions make unusual pets and can be obtained from breeders. They are generally kept in glass tanks or terrariums. The bedding needs to be soft and at least five inches deep so that the animal can burrow. The terrarium should contain other hiding places as well. It must also be kept warm. The animals eat live insects such as crickets and require a source of water as well as food.
Whip scorpions are said to be entertaining pets but need to be handled with care. It's important that their spray doesn't enter the eyes or open wounds. In addition, although many individuals are much less ready to bite than camel spiders, the animals will bite if they feel threatened.
Wind Scorpions or Camel Spiders
Some people do keep camel spiders as pets, but they not as suitable for keeping in captivity as whip scorpions. Camel spiders are very active animals. In addition, although some people handle pet whip scorpions, the camel spider is not as "happy" in this situation and is likely to inflict a painful bite. Pet owners recommend that people either don't handle a camel spider or that they pick it up with tongs.
Whip scorpions and camel spiders are intriguing creatures. There's still a lot to be learned about their lives in the wild. It will be interesting to see what else researchers discover about these strange arachnids in the future.
Questions & Answers
I have seen a camel spider in Kuwait whose body length alone was over ten inches, so why do they say that the animals are smaller?
I suggest that you contact a scientist involved in camel spider research. I think he or she would be very interested in your personal observations about the size of the animals. Scientists say that the animals are small, but there may be some significant facts about camel spiders that they haven’t discovered. The papers described or linked to in the articles below should enable you to find a way to directly or indirectly contact a researcher.
© 2012 Linda Crampton