Sonoran Desert

Fangs & Stingers

Tarantulas and scorpions are cousins. They are scary looking creatures that look like monsters from outer space. Both are actually very shy creatures that really want nothing to do with humans. There are no tarantulas in Arizona or the United States that are considered dangerous to humans. You are in more danger from fainting and hitting your head than you are from the bite of a desert tarantula.

There are 36 different kinds of scorpions that live in Arizona. But only one species—the Bark Scorpion—has venom potentially strong enough to kill a person. Don't give yourself nightmares. The last documented case in Arizona of a person dying from a scorpion sting occurred in 1948.

Tarantulas and scorpions are arachnids. Arachnids belong to the largest group of animals now living on the Earth. Arthropoda is the scientific name for this group, which scientists call a phylum. Creatures in this group are called arthropods.

The phylum Arthropoda includes arachnids such as spiders, scorpions, ticks, and mites. It also includes centipedes, millipedes, crustaceans such as crabs, shrimp, and lobsters, and millions of kinds of insects.

Arachnids are not Insects!

Arachnids have only two major body sections: Cephalothorax and abdomen.

Head and thorax are fused to form the Cephalothorax
Eight walking legs
Thin waist connects two body parts
Many eyes. As many as 6 or 8.
No antennae
No wings

Phylum Arthropoda

Class Arachnida: Includes spiders, scorpions, mites, and ticks

Class Insecta: Includes beetles, flies, bees, crickets, grasshoppers, moths, butterflies, wasps, mantids, cockroaches, etc.

Insects ARE NOT Arachnids

Insects have three major body sections: Head, thorax, and abdomen.

Head contains the eyes, mouthparts, and one pair of antennae
Six walking legs attach at the thorax
One or two pair of wings attach at the thorax
One set of large compound eyes

Fangs!

There are more than 36,000 known species of spiders. About 2,500 kinds of spiders live in North America.

Tarantulas catch insects and tear them into pieces. The pieces are rolled into a large bug "food ball." The spider then gushes digestive fluids onto the "bugball" and slurps in the gooey bug stew. Hard pieces are left behind.

In the Sonoran Desert, tarantulas spend most of their lives living inside small burrows that they dig in the desert soil. They leave the burrow at night to hunt for insects like crickets, grasshoppers, beetles, cockroaches, and other small creatures, including mice, lizards, and other spiders.

After mating, the female tarantula builds an eggsac. She deposits anywhere from 100 to 1,000 eggs inside. The number of eggs depends upon how well the tarantula has been eating, the age of the spider, and other factors.

In order to grow larger, tarantulas must molt. During molting, the tarantula sheds its exoskeleton. The spider turns on its side or back to molt. It can take several hours or as long as a day for an adult tarantula to complete a molt.

Better to be a girl? Most male tarantulas only live between six and 18 months. Female tarantulas can live for 20 or 30 years, depending on the species.

Tarantulas love to eat insects. Some of the larger jungle species will often eat baby mice, lizards, frogs, and even small snakes.

The Mexican redknee taranatula can produce up to 1,000 spiderlings at a time.

There are no tarantulas in the United States considered dangerous to humans.

Tarantulas living in the rainforests of South America or Central America are called "arboreal spiders." Arboreal means "living in the trees."

A biologist who specializes in the study of spiders is called an Araneologist.

Arachnology is the scientific study of arachnids.

A spider's front jaws are called chelicera. The chelicera includes the fangs.

The Tarantula Hawk is a large wasp. It is just one of almost 300 kinds of wasps in North America that are dangerous enemies of tarantulas and other types of large spiders. The Tarantula Hawk uses a large stinger to paralyze the spider. It then lays a single egg on the body of the spider. When the egg hatches, the maggot-like larva burrows into the living spider and begins to feed. The spider is helpless. It actually may live for weeks or months as the wasp larva devours him from the inside out.

Stingers!

"Chela" is the name for the scorpion's pincer-like appendages.

There are 36 known species of scorpions that live in Arizona and the Sonoran Desert.

The Giant Desert Hairy Scorpion (Hadrurus arizonensis) can grow 5 to 6 inches long. It can live for 25 years or more. Others types of scorpions might live less than one year.

Fossil evidence indicates that ancestors to modern scorpions might have been swimming in ancient oceans as long as 450 million years ago.

The Bark Scorpion is the most dangerous scorpion in Arizona. It has venom that is potentially deadly to infants, small children, or older people in poor health.

In Arizona, the last documented case of death by scorpion sting occurred in 1948.

The Bark Scorpion's scientific name is Centruroides exilcauda. Centruroides means "in the form of Centrurus." Centrurus means "pointed tail." Exilcauda is a combination of Latin words that means "slender" (exili-) and "tail" (cauda).

Bark Scorpions like to hide under rocks, logs, the bark of trees, in cactus holes, or in cracks and crevices. Watch where you put your hands and feet!

Scorpions have eyes, but do not see well. They have hairlike organs on their tail, legs, and pincers that are very sensitive to vibrations.

Scorpions walk with their pincers extended.

Scorpions glow in the dark. When seen under ultraviolet light (black light), they fluoresce (glow) greenish blue or greenish yellow.