Camel Spider - danger or myth

Author: Anders Nielsen | Ctrl-D saves this page

The Camel spider belongs to the order Solifugae of the class Arachnida. It relates to both spiders and scorpions, but is neither one. The Greeks were the first to recognize Camel Spiders as an individual group of animals and gave them the name phalangium because they appear to have five legs^[1].

Camel Spiders vs. scorpions and insects

Camel spiders relate to the other arthropods, but several hundred million years ago a divergence between the two lines occurred. And they really are different, as e.g. the breathing system of Camel spiders is derived from that observed in insects^[2]. This system with trachea allows for a relatively fast oxygen uptake when necessary, and hence the possibility of moving fast.

Camel spiders are also known as Sun Spiders, Beard Cutters (due to their large jaws), Wind Spiders and Wind Scorpions. The name solifugid means « escaping from the sun », which is very characteristic of Camel spiders in terms of behavior.

They are not dangerous, but because of their appearance, and the many myths circulating about them, primarily by soldiers deployed in Iraq and Afghanistan, Camel spider have a reputation as brutal and merciless desert animals.

A camel spider as they are found in California

Myths about Camel Spiders

The myth circulating about their size, such as the they can grow as large as dinner plates, never disappear because of the infamous hoax image showing two camel spiders tied together.

The hissing sound they can generate also generates various myths. It generates the hissing sound by a stridulatory organ^[3]. A recent study showed that the stridulatory organ had a similar morphology in all developmental stages of the Camel spider. The conclusion from the study was that the hissing had a defensive purpose (ibid).

Habitat - fleeing from the sun

Camel spiders prefer dry, sandy areas and are geographically found in Northern Africa and in the Middle East, including Iraq and Afghanistan. In these semi-arid environmental conditions they seek shade by following the shade whenever their sensory organs sense it.

Camel spiders, like Solifugids, are nocturnal animals. Soldier claims that Camel Spiders chase people in the Iraqi desert but it is, of course, also according to scientists, the shadow that the animals are seeking.

Bites

Camel spiders are neither dangerous nor venomous, and humans have nothing to fear from Camel spiders. The hoax about how dangerous Camel spider bites are is purely an anecdote. Although a bite is probably painful, only the bacteria in its mouthpart will be capable of hurting you.

Diet

Camel spiders are carnivorous and eat a variety of animals that they kill with their strong chelicerae. Its diet includes small rodents, spiders, insects, termites, and small reptiles. They are not strong enough to capture and kill large mammals, but occasionally they catch undersized birds.

Hunting

Camel spiders can move at velocities of almost 10 miles per hour. They oxygen uptake capacity is high which explains why they can move that fast. A side-effect of their high metabolic activity is a short life-span.

Appearance

When stretched out, Camel spiders can reach a length of five inches although the average size is somewhere between ½-3 inches. Their abdomens have 11 segments and there is no intermediary segment separating head from abdomen. They have two clearly visible eyes and five so called "racket organs". These organs are probably rudimentary eyes, as scorpions have five very small eyes.

Camel spiders are covered with hairs and spines that allow them to move quickly and sense vibrations in their surroundings.

Mating behavior

In his study from 1966, Martin Huma^[4] divides the mating habits of solpugids into three phases. The first phase is the attack phase, the second phase is the contact phase, and the third phase is the transfer phase. In the attack phase, either the male or female assumes an attacking position by raising the first pair of legs. In this phase, the male initiates the contact phase by a jump forward towards the female. This either results in a combat between the two, or a complete submission by the female where the male grabs her with his chelicerae. If she does not fight him so much that he flees, the male with copulate with the female to impregnate her with offspring.

The presented phylogenetic tree indicates how Camel spiders share the same common ancestor as spiders and scorpions.

Systematics of Solifugae or camel spiders

Systematics of Arachnids

The solifugae order and its evolution

The Solifugae is a distinct evolutionary lineage. The first Solifugae probably evolved in the Mesozoic Era around 250-65 Million years ago as ancestors of primordial scorpions arising from the sea. The picture above shows how Camel spiders are related to both scorpions and true spiders. It is obvious that they are closer related to scorpions.

Arachnida consist of 10 orders (see below) of which the camel spider (Solifugae) is one of them. Within the camel spiders there are approximately 900 species in six different families.

Table: Various orders within the Class Arachnida

Acari	Mites and ticks
Araneae	True spiders
Opiliones	Harvestmen
Palpigradi	Micro-whip scorpions
Pedipalpi	Whip Scorpions
Pseudoscorpiones	Pseudoscorpions
Ricinulei	Ricinulids
Scorpiones	Scorpions
Solifugae	Camel Spiders

Camel spiders vs. spiders and scorpions

Although Camel spiders look similar to spiders and scorpions, they are different. They neither have venom nor silk glands, and they kill and chew their prey with their powerful jaws.

Educational Quiz

The questions in this test can be answered if you read the text carefully, and see the video. Please take your time.

After each question, make a note with either A or B. After the quiz, you will get the answers

1. Who were the first to recognize Camel spiders
as a separate group of animals?

2. How many Camel spiders did you see in the video?

3. Are Camel Spiders true spiders?

4. Where does Camel Spiders prefer to stay?

5. How many segments have the abdomen of a Camel spider

6. How big are the largest Camel Spiders?

7. How fast can camel spiders run?

8. What are Camel Spiders?

9. When did Camel Spiders diverge from the other arthropods?

Go to this site this site to see how many correct answers you got.

References

¹Fred Punzo, The biology of camel-spiders (Arachnida, Solifugae) (1998)
²Lighton & Fielden, Gas Exchange in Wind Spiders (Arachnida, Solphugidae): Independent Evolution of Convergent Control Strategies in Solphugids and Insects. J. of Insect Physiol Vol 42(4), pp 347-357 (1996)
³Hruskova-Martisova et al., Analysis of the stridulation in solifuges (Arachnida : Solifugae). J. of insects behavior 21(5) pp. 440-449 (2008)
⁴Muma, Martin H., MATING BEHAVIOUR IN THE SOLPUGID GENUS EREMOBATES BANKS. J. of Animal Behaviour 14(2-3) pp. 346-350 (1966)

Web resources

Desert Scorpions
BBC video
Sun scorpions in Canada
Scorpions of South Africa
Camel spider picture
C.S. info and pictures

Acknowledgements

Thanks to James, Mayra and John for giving me the permission to use their photos.

Contact information

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