Introduction to Spiders
Spider, an animal closely related to mites, ticks, and scorpions. There are about 35,000 known species, more than 3,000 of them in the United States. Spiders live almost everywhere—in soil, under rocks, on grasses, on tree branches, in caves, and on water. Spiders are not insects, although they belong to the same phylum of animals as insects. They differ from insects in that they and wings and have eight, instead of six, legs.
Spiders are known for the silk webs they spin to trap their prey and for their venomous bites. However, not all spiders spin webs and, although most species have poison glands, only a few species are poisonous to humans. In the United States, the most poisonous spiders are the female black widow spider and both sexes of the brown recluse spider. Most spiders are helpful to humans, killing insects harmful to animals and plants.Spiders are eight-legged, fanged arachnids that hunt or build webs to catch food.
Spiders are invertebrates—they lack a backbone—and they do not have an internal skeleton. Instead, the entire body is enclosed in a hard, protective covering called an exoskeleton. The exoskeleton is made of protein and strengthened by a substance called chitin. Sensitive hairs and spines cover the exoskeleton.
Spiders vary greatly in size and color. In body length they range from 1/50th of an inch (0.5 mm) to 3 1/2 inches (9 cm). Most spiders are gray, black, or brown, but some are such vivid colors as green or red and others have colorful markings on their bodies.
The spider's body has two major regions—the cephalothorax, which consists of a fused head and thorax, and the abdomen. The two regions are separated by a tapered area called the pedicel. At the front of the cephalothorax are the eyes, usually four pairs, and the mouth. The mouth is adapted to sucking—spiders do not chew their prey, but instead suck out the internal juices from their victims.
Six pairs of appendages are attached to the cephalothorax—one pair of chelicerae, one pair of pedipalps, and four pairs of walking legs. The chelicerae terminate in fangs, which contain a poison that paralyzes or kills prey. (Most spiders feed on insects; the larger species feed on small fish, birds, and reptiles.) The pedipalps are used as feelers and to hold the prey during feeding. (In male spiders, the pedipalps are also used to transfer sperm to the female.)
In the abdomen are the respiratory, or breathing, organs. Most spiders have two types—(1) a pair of lunglike organs, called book lungs; and (2) tracheae (air-carrying tubes that branch from the outside to all parts of the body). Near the tip of the abdomen, on the underside, are specialized organs, called spinnerets, from which the spider spins out its thread-like strands of silk. A spider usually has six spinnerets. Some spiders have an additional spinning organ called a cribellum, for spinning out special ribbon-like strands of silk.
Spiders usually lead solitary lives. Most kinds of spiders are aggressive. After mating it is not unusual for the females of some species to kill the male, which is ordinarily quite a bit smaller than the female. (This behavior accounts for the name of the black widow spider.) Mating may or may not be preceded by courtship, depending on the species. After mating, the female retreats to a nest, often made of silk, in which she lays her eggs.
The female may lay from 2 eggs to 3,000 eggs, depending on her size and the species. In general, the larger the female, the more eggs she lays. The eggs are covered by a cocoon made from silk. As the young spiders (spiderlings) grow, they molt their exoskeleton and grow a new one to accommodate their increasing size. Most spiders live for a year or less. Some of the larger female tarantulas, however, may live for 20 years or more.Spiderlings stay within the egg sac until their first molt.
You see a small creature scurry across the floor. But you aren’t sure if it is a spider or an insect. How do you decide? Do what scientists do. First, they take a close look at the animal. They count its legs. They count its body parts, too. These are the best clues to use when deciding if a creature is a spider or an insect.
Count the legs. Did you count six legs, three on each side? An insect has six legs. Did you count eight legs? A spider has eight legs, not six. If you count the body parts, you see another difference. An insect has three main body parts. A spider has only two main body parts.
Legs and body parts are just two ways in which insects and spiders are different.
Most spiders eat insects and other spiders. A few large spiders eat frogs, birds, or small lizards. But all spiders kill their prey with a poisonous bite. A spider bites its prey with its fangs, which are long, pointed teeth. Poison, called venom (VEHN uhm), flows through the fangs. The venom stuns or kills the spider’s prey.
Now the spider has a problem. It has no chewing parts in its mouth. It cannot eat its prey by chewing. Instead, the spider sucks the liquids from its prey. A spider may also spray special juices from its mouth onto the prey. These juices turn the prey’s body into a soupy liquid. Then the spider can slurp up its meal.
But what if the spider isn’t hungry? A spider simply stuns its prey. Then it spins and weaves a silk case around the prey. The spider hangs the prey on its web or puts it in a safe place. When the spider does get hungry, it has a meal waiting.
The Spider's Silk and Web
On the tips of its spinnerets are many fine tubes through which the spider draws out a fluid produced in glands in the abdomen. The fluid hardens into individual strands. By bringing the tips of the spinnerets together, the spider unites the strands into a single thread.
Spider's silk is extremely strong and has a great deal of elasticity. It is extremely thin and lightweight; a thread long enough to reach around the world would weigh less than six ounces (170 g). The term cobweb is often used to describe one or more individual threads. It is also used as another term for a spider's web.
Spider silk is similar to, but not identical with, the silk produced by the silkworm and similar caterpillars. Spider silk, however, is of little value commercially. It does not stand up well to the weaving process, and attempts to weave fabric from spider silk have resulted in fabrics lacking luster and other desirable qualities. It was once used extensively for cross hairs in telescopic sights and other optical instruments, but has been largely replaced for this purpose by platinum wire and glass etching.
Besides using silk to build webs, nests, and cocoons, spiders also use silk for traveling. To lower itself a spider fastens a thread to a twig or other object and then swings off, paying out thread as it falls. This type of thread is called a dragline. The spider often uses the dragline to escape danger, quickly climbing on it to get back to its point of attachment. Many spiders spend their entire lives attached to a dragline.
Many spiders, especially young ones and very small ones, use their silk for a method of travel called ballooning. In ballooning, a spider releases silk threads from its spinnerets. As the wind blows, air currents take hold of the silk and carry the spider along. By this method spiders can be carried for great distances—some have been found more than 50 miles (80 km) out to sea.
There are many kinds of web-building spiders and many kinds of webs. Some spiders build funnel-shaped webs, some build webs that are flat or curved sheets. Some webs are messy jumbles of threads, while others, called orb webs, have a beautiful spokelike pattern.
Spiders spin many kinds of webs. But all webs are used for the same thing—to capture prey.
The threads in a spider web are thin and hard to see. If an insect comes along, it may not see the web until it is too late. Its legs and body get stuck on the sticky strands of silk. The more the insect struggles, the more trapped it becomes.
Some spiders sit and wait in the middle of their webs. The spider may not see a trapped insect. But the spider can feel it tug and pull on the web. The spider knows that dinner has arrived.
Other spiders sit on the edge of their webs. When they feel tugs, they use draglines to swing down onto their prey.
Many people think that orb weavers spin the prettiest webs. These webs are especially beautiful when they are wet with morning dew or covered with frost.
Orb webs are large and round. The main threads look like the spokes on a bicycle wheel. These threads are made up of dry silk. Threads of loose, sticky silk connect the spokes. The sticky threads are the ones that trap the spider’s prey.
Why doesn’t a spider get caught in its own web? There are two reasons. First, a spider knows where the sticky threads are in its own web. It can avoid these threads. Second, spiders have special claws on their feet. The claws keep a spider from losing its grip and falling onto the sticky strands.
Orb weavers are fussy builders. A spider may tear down its web each night and build a new one. It may even eat the old web to recycle the silk.
Some spiders spin tangled webs with threads that go every which way. Others spin sheet webs that hang like hammocks between leaves and branches. Still others spin funnel webs.
A funnel web is shaped like a funnel—wide at one end and narrow at the other. The funnel-web spider hides in the narrow end. It waits for an insect to fly or to crawl into the wide end of the web. As the prey struggles to free itself, the spider runs out and kills it.
Funnel-web spiders are sometimes called grass spiders. This is because they usually build their webs in the grass or along the ground.
Spiders spin webs to capture prey. They wrap their prey in silk. They spin nests to live in. But most female spiders also spin silk sacs to hold their eggs.
The number of eggs a female lays depends on her size. An average-sized female lays about 100 eggs at a time. A large spider may lay as many as 2,000 eggs at one time.
After laying her eggs, a female spider wraps them in a silk cocoon called an egg sac. Then she puts the egg sac in a safe place. Some spiders hang their egg sacs in their webs. Others attach them to leaves or plants. Still others carry their egg sacs with them.
Spiderlings, or baby spiders, hatch inside the egg sac. But they don’t come out right away. They need to be able to spin their own silk before they can leave the safety of the sac.
Kinds of Spiders
Spiders make up the order Araneae of the class Arachnida, phylum Arthropoda. The order is generally divided into three suborders—Liphistiomorphae (or Mesothelae), which consists of about 40 primitive species found in Asia; Mygalomorphae (or Orthognatha); and Araneomorphae (or Labidognatha).
The suborder Mygalomorphae includes the tarantulas and trap-door spiders. These spiders do not build webs; they catch their prey by hunting.
(family Ctenizidae), found in the southern United States, build a tube-like nest about 6 inches (15 cm) into the ground and line it with silk. The cover of the nest is a silk-hinged lid made of silk threads, twigs, dirt, or cork. The spider often waits just under the partly open door until an insect or other prey wanders by.The trap-door spider sets a trap for its prey.
The suborder Araneomorphae contains most species of spiders. Members of this suborder are usually divided into two groups—hunting spiders and web-building spiders.
Hunting spiders include the wolf spiders, crab spiders, and jumping spiders.
(family Lycosidae) are active hunters and chase insects and other prey. By day some of these spiders hide under stones or wood or in grass but others are active in bright sunshine. The female wolf spider carries her young (as many as a hundred) on her back until they can care for themselves.Wolf spiders are active hunters and chase insects and other prey.
A wolf spider has silk glands, but it doesn’t spin a web. A wolf spider is a hunting spider. Like most hunting spiders, it has good vision. It runs after and pounces on its prey. The wolf spider leaps into the air to catch a flying insect. But this fierce hunter is a very gentle parent.
A female wolf spider attaches her egg sac to her spinnerets and carries it with her. She guards the egg sac. She inspects it and repairs it. When the eggs are ready to hatch, she breaks open the sac so that the spiderlings can get out.The spiderlings travel on their mother’s back. They hang on tightly to hairs there. If a spiderling falls off, it follows its mother’s dragline to find her. Then it quickly climbs up one of her legs.
(family Thomisidae) have two pairs of legs shorter than the others and, like crabs, walk sideways. They can also walk forward and backward. They have large, flattish bodies and live on walls, fences, and flowers. They stalk their prey.
Crab spiders don’t spin webs or build traps. They are sit-and-wait hunters. They sit on flowers and wait for insects to arrive. Why don’t insects notice them? Crab spiders can camouflage (KAM puh flahzh), or hide, their bodies. Some change color to match the color of the flowers they sit on.
Crab spiders blend into their surroundings in other ways, too. Some have white and gray spots on their bodies. They pull their legs in and sit on leaves or plants. These spiders can look like bird droppings.
Crab spiders are small. Most are no bigger than flies. Yet a crab spider can kill an insect much larger than itself. When a crab spider is finished sucking the liquids from its prey, all that is left is the prey’s exoskeleton.
(family Salticidae) leap on their prey with great skill. They are often brightly colored and possess the best eyesight of all spiders. The males do an elaborate courtship dance.
Web-building spiders include the black widow spider, the brown recluse spider, garden spiders, grass spiders, common house spiders, and water spiders.
Some jumping spiders can jump 40 times the length of their bodies, but they don’t jump for exercise. They jump to capture prey. And jumping spiders don’t wait for prey, as most hunting spiders do. Jumping spiders have the best eyesight in the spider world. They use their vision to stalk, or follow, prey. Then they pounce.
A jumping spider anchors its dragline to a surface, leaps into the air, and prepares to land on its prey. When the spider lands on its prey, it sinks in its fangs and holds on.
(Latrodectus mactans) is found throughout the United States and Central and South America; it is especially plentiful in the southern part of the United States. Black widows live in cool, dark places. The webs they make have irregular shapes. The female's bite can be fatal to humans, but less than 10 per cent of the bites are. The female has a shiny body that is about one-half inch (13 mm) long. On the underside of the abdomen it has a red, hourglass-shaped figure. Black widows belong to the family Theridiidae.The black widow is a venomous spider with an hourglass-shaped red mark on the underside of the abdomen.
Female black widows sometimes kill and eat their mates. With their mates dead, the spiders are now “widows.” And that’s how black widows got their name.
A female black widow doesn’t always eat her mate. But like most web weavers, her vision is poor. She sometimes mistakes her tiny mate—who is only about one-fourth her size—for a tasty meal.
Most female black widows weave tangled webs in dark places. They build webs under fallen logs or in the corners of barns and sheds. If you see a black widow, don’t touch it. Its bite is harmful to humans. It can cause illness and even death. Fortunately, the spider bites only as a last defense.
You can recognize a female black widow by the red or yellow hourglass shape on its abdomen. With its legs stretched out, a female is about 11/2 inches (3.8 centimeters) long.
(Loxosceles reclusa), found throughout much of the eastern half of the United States, can inflict a dangerous bite causing formation of a gangrenous lesion. Although the bite itself is not fatal, it may allow secondary infection to enter. These spiders live in dark corners and crevices, and do not bite unless disturbed. The body, colored from fawn to chocolate brown, is about one-half inch (13 mm) long. These spiders can be identified by a violin-shaped mark on the cephalothorax. The brown recluse spider belongs to the family Loxoscelidae.The brown recluse is a venomous spider with a violin-shaped mark on its back.
(family Araneidae) are noted for their orb webs. A common garden spider of the United States, sometimes called the orange spider, is about one inch (2.5 cm) long. The abdomen is black with yellow or orange markings, and the cephalothorax is gray above and yellow beneath.
(family Agelenidae) spin sheet webs that are funnel-shaped in the center. The spider usually hides in the funnel, ready to seize any insect that lands on the web.
There are hundreds of species, belonging to various families. House spiders are usually quite small. The bodies are dull colored (often gray) and are generally marked with darker spots and lines. House spiders generally spin loose, irregularly shaped webs in seldom-used areas of homes and other buildings.
There are many spider species of various families that live on the margins of rivers, ponds, and other bodies of water. Many of them can run on the surface of water. It is not unusual for water spiders to catch and eat small fish. One European species (Argyroneta aquatica) lives below the surface in a watertight, dome-shaped, silken chamber. In the chamber the spider stores air trapped among its body hairs. When its air supply is low, the spider rises to the surface, traps more air, and returns to its chamber.
In a way, water spiders can breathe underwater. Water spiders live in underwater webs shaped like small bells. Each bell has an opening. A water spider carries air bubbles from the surface of the water and takes them into its bell. The bubbles slowly push all the water out of the bell, leaving the air trapped inside. A water spider can live on the air in its “diving bell” for several months.
Inside its bell, a water spider waits for a water bug to swim by or for a flying insect to fall into the water. Then the spider swims to grab its prey and bring it back to its underwater home.
Water spiders are the only spiders that live most of their lives underwater. These special spiders live in the lakes and ponds of Europe and in parts of Asia.
Tarantulas (family Theraphosidae) are very hairy, and among them are the largest of all spiders. One species, found in South America, has a body length of more than 3 inches (7.5 cm) and a 10-inch (25-cm) leg span. The largest tarantula found in the United States has a body about 2 inches (5 cm) long and a leg span of about 4 or 5 inches (10 or 12.5 cm). If handled roughly, tarantulas may inflict painful, but not fatal, wounds.Tarantulas are some of the world's largest spiders.
Tarantulas have a body that is divided into two main parts—the abdomen (AB duh muhn) and the cephalothorax (SEHF uh loh THAWR aks or SEHF uh loh THOHR aks).
The abdomen is the rounded part at the back of the tarantula that contains the animal’s organs. The cephalothorax is at the front of the tarantula, and it contains the mouthparts, including the chelicerae (kuh LIHS uh ree). The chelicerae are above the spider’s mouth opening, and the spider uses them to seize, crush, and kill its prey. Each chelicera ends in a sharp, hard, hollow fang. Eight eyes, eight legs, and two leglike structures called pedipalps are also connected to the cephalothorax.
One of the most popular kinds of tarantula kept as a pet is the pinktoe. As you might expect from its name, the tips of a pinktoe’s legs are pink. A pinktoe has an abdomen that is usually black and a brown cephalothorax.
Pinktoes live in tropical regions (areas near Earth’s equator that have mostly warm temperatures the year around and plentiful rainfall). Pinktoes live in tropical areas of South America, Central America, and Mexico, and on some islands in the Caribbean Sea.
Many kinds of tarantulas live in burrows in the ground, but pinktoes are arboreal tarantulas. The word arboreal relates to trees, and pinktoes are called arboreal because they mostly live in trees.
Some kinds of pinktoes, however, live among plants—especially tall grasses—or in houses and other buildings.
A pet pinktoe does not have a personality in the same way that a pet dog or cat would. The pinktoe, like most other tarantulas, will probably spend most of its time hiding. It will climb to the top of the container it lives in, spin a hiding place from silk, and stay there. It may come out for feeding time, but it probably will not move around its container very much.
Still, different species of tarantulas do behave differently. Some species are very fast moving. Such tarantulas are quick to attack any “intruder” in their container, which could include the hand of the person trying to feed and care for them.
Pinktoes, however, are not usually aggressive. They are gentle, calm, slow moving, and even friendly. They rarely bite.
Finding a pet pinktoe should not be very hard. You can buy one from a pet store or from someone who raises tarantulas, such as a breeder. If you buy your tarantula from a breeder, he or she can teach you about the proper way to care for a pinktoe.
Try to buy a female pinktoe if you want your pet to be likely to live for a long time. Female tarantulas may live 20 years or more. Males usually live only a few years.
If you do not want to spend a lot of money on a pet tarantula, you may want to try a spiderling, or young spider. Spiderlings may be harder to feed, though, because they need to eat very small insects. But, with a spiderling, you can have the fun of watching your young pet grow and molt more frequently than an adult would.
Like other tarantulas, pinktoes are completely carnivorous. This means that they eat only other animals and never eat plants. Pinktoes mostly eat insects. They do not chase and capture their prey. Instead, they wait quietly near their home for prey to come to them.
A pinktoe uses its chelicerae to grab insects that pass by its home. Once a pinktoe has a grip on its prey, it stabs its prey with fangs. Poison, called venom, flows through the spider’s fangs and into its victim. The poison stuns the animal so that it cannot fight back. Then, the pinktoe sprays digestive juice over the prey, turning it into a thin “soup.” Spiders have mouthparts that can be formed into something like a straw. This allows the spider to suck up its liquid meal.
The time it takes a tarantula to consume a meal depends on the size of the prey. A cricket may be turned to liquid and sucked up in an hour. A full-grown mouse might take 24 hours. When the pinktoe is finished eating, all that is left of the prey is a small ball of remains.
If you have an adult pinktoe, it should be fed once a week. If you have a younger pet that is still growing, feed it twice a week or more. Crickets, cockroaches, and grasshoppers are all good food for pinktoes. You can also feed your pinktoe mealworms. Do not, however, feed your pet insects that you capture yourself. Insects you capture may have pesticides (bug-killing poisons) on them. Also, do not feed your pinktoe any insect that may be dangerous to your pet, such as ants, wasps, and stinkbugs.
You can buy crickets or other insects to feed your pinktoe at a pet store. When your pinktoe has finished eating, remove the remains of the meal or any uneaten food right away.
Spiders spin silk to make many kinds of structures. Like all spiders, pinktoes spin silk to create a home and to make an egg sac. Unlike many spiders, however, pinktoes do not spin silk to make webs for catching prey.Pinktoes and other tree-dwelling tarantulas spin their homes in the shape of a tube they can hide in or in the shape of a small hammock they can rest in.
Other kinds of tarantulas live underground. These tarantulas dig burrows for their home. These tarantulas do not spin webs to catch prey, but they do line their burrows with silk that they have spun. They may also leave a few strands of silk trailing out from the burrow’s opening. If an animal crosses or touches this silk strand, the tarantula is alerted and knows to come out and look for a meal.
You can keep a pinktoe in an aquarium (uh KWAIR ee uhm) tank, a plastic container, or a homemade container. Your pinktoe’s home needs a tight-fitting cover to keep the spider from escaping.
Your pinktoe can stay healthy only if it is kept warm and moist. A temperature from 72 to 79 °F (22 to 26 °C) is good. Use vermiculite—a type of flaky, layered mineral—on the bottom of the container to hold moisture. Mist the tank often to provide moisture for your pet to drink. Tree-dwelling spiders like drinking water off the sides of the tank better than out of a bowl of water.
Because pinktoes are tree dwellers, give your pet a container tall enough to allow it to climb. For a full-grown pinktoe, a container that is 8 to 10 inches wide, 8 to 10 inches deep, and 12 inches high (20 to 25 centimeters wide, 20 to 25 centimeters deep, and 30 centimeters high) is fine. Provide a small tree branch that your pinktoe can climb on and attach its silky home to.
As a general rule, it is not a good idea to keep more than one tarantula in the same container. Tarantulas will eat their own kind. If two tarantulas are kept in the same cage, one of them will almost certainly become dinner for the other.
Pinktoes have no need for companionship. To avoid all risk of one pinktoe killing the other, it is best to give each its own container.
In general, female tarantulas tend to be larger than males. There are several possible reasons for this. One is that the female’s body stores nutrients used to form eggs. Another reason is that her body has special reproductive organs. She also has larger glands for spinning silk.
Male tarantulas may look daintier than females. They usually have smaller bodies. Their fangs are also thinner and narrower than those of females. The legs of a male tarantula are longer and thinner than those of a female.
A young dog is a puppy. A young spider is a spiderling.
For pinktoe spiderlings to hatch, first, the male gets ready for mating by spinning a small net of silk. Next, he releases sperm from his body onto the silk. Then he collects the sperm in special organs in the tips of his pedipalps. When he is ready to mate, he approaches the female. If she is ready, she allows him to place his sperm into her body.
The female pinktoe lays eggs several weeks or even months after mating. First, she spins a thick net of silk. Then, she lays eggs inside the silk. The eggs combine with the stored sperm as they pass out of the female’s body. She lays between 50 and 125 eggs. When she is done, she wraps the silk around the eggs to create an egg sac.
Pinktoe spiderlings hatch from their eggs about 7 to 8 weeks later as tiny, fully mobile spiders.
Like all tarantulas, pinktoes have hairs, called setae (SEE tae or SEE tee), all over their legs and body.
Pinktoes use their setae for many purposes. Setae on the legs are used to sense vibrations in the air and on the ground. Thick mats of setae on the feet allow pinktoes to climb up smooth surfaces with ease. Other types of setae on the feet allow the animal to taste its food, while setae around the mouth filter the food.
Many tarantulas, including pinktoes, have special setae that help them defend themselves. These are called urticating (UR tuh kay ting) hairs. Urticating hairs are sharp, with very tiny barbs, or hooks, at the end of them. These hairs dig into the skin, and even the eyes, of an enemy, causing burning and irritation. A pinktoe must brush against an enemy to drive the urticating hairs into the enemy’s skin. But other tarantulas can use their legs to kick hairs off and throw them at an enemy.A Tarantula's bark can be worse than its bite.
Luckily, pinktoes rarely bite. If they do, their bite—like that of most other tarantulas—is only mildly venomous (poisonous). Some people compare a tarantula bite with a bee sting. Tarantula venom is dangerous only to people who are allergic to it. There are no known cases of a person dying from a tarantula bite. However, a tarantula’s bite can be painful, and its fangs can cause nasty puncture wounds. If you are bitten, let an adult know immediately.
Treat a tarantula bite like any other animal bite. Wash the bite with soap and warm water. Put on an antiseptic ointment and a bandage, if you need one.
It is more likely that you may get stuck with your pinktoe’s urticating hairs—the bristly spines on its abdomen. This can be very uncomfortable. Use tweezers to remove the hairs from your skin. If hairs should get into your eyes or nose, see a doctor.
Most experts do not recommend holding any tarantula. It is dangerous to pick up or touch a tarantula from any of the fast, aggressive species. Not even an experienced tarantula keeper would do this.
Although pinktoes and other gentle tarantulas are usually calm, they can bite. The spider’s urticating hairs also can cause an uncomfortable skin rash or more serious harm to the eyes and nostrils.
Holding a tarantula can be dangerous to the spider as well. Tarantulas have fragile bodies. Dropping a tarantula could injure its abdominal area, which could be fatal to your pet. Always be gentle and careful when you move your tarantula. You may gently lift the tarantula with tongs. Or, you may use a paintbrush with a long handle and soft bristles to carefully place the tarantula into a container.
Besides pinktoes, there are a number of other mild-mannered tarantula species. These tarantulas include the Mexican redleg, the Mexican redrump, the Mexican redknee, the Chilean rose, and the curlyhair. All of these are ground-dwelling tarantulas from North or South America. They all make good pets for anyone—even a beginner—interested in having a spider for a pet. One downside of all these gentle tarantulas is that they, unlike pinktoes, do have the ability to throw off urticating hairs.
Mexican redlegs and Mexican redknees are beautiful black spiders with either orange or orange-red stripes around their legs. Mexican redrumps are black with a red abdomen. Curlyhairs have orange hairs on their legs and abdomen. Chilean roses can have a gray undercoat with gray and beige, pink, or copper-colored hairs.
Even though certain types of tarantulas might be available for sale as pets, they may be difficult for people who are new to caring for spiders.
For example, some species have special or unusual needs that make them harder to care for. The Trinidad chevron, which needs very high humidity, is one such spider.
Other difficult tarantulas include the Brazilian salmon, the Goliath birdeater, the king baboon tarantula of Africa, the Sri Lankan ornamental, the cobalt blue, and the Australian tarantulas (also called whistling or barking spiders). Large size, beauty, or interesting behaviors may make all these tarantulas tempting pets, but they are recommended only for experienced spider owners.
All of the tarantulas mentioned above are aggressive and fast moving. The venom of the king baboon tarantula is also more dangerous to humans than the venom of most other tarantulas.
The world’s largest tarantula is the Goliath birdeater tarantula.
This tarantula lives in the rain forests of South America. Its leg span can be more than 10 inches (25 centimeters)—that is about the size of a small dinner plate.
When it feels threatened, the Goliath birdeater rubs the bristles on its legs together to make a loud hissing noise. This noise is called stridulation (STRIHJ uh LAY shuhn). The Goliath has other defensive moves as well. It can rear up on its hind legs to intimidate an enemy, and it also throws its urticating hairs when it feels afraid.
Although it is called “birdeater,” this tarantula’s diet is not limited to birds. The Goliath birdeater also eats frogs, toads, lizards, mice, and small snakes.
The smallest known tarantulas grow only from about 1⁄2 inch to about 1 inch (about 1.25 to 2.5 centimeters) across.
Some of these dwarf tarantulas are found in the genus called Cyriocosmus from Central and South America. Some Cyriocosmus tarantulas are beautifully patterned with red and black markings.
Another dwarf tarantula is Aphonopelma paloma, a tarantula from Arizona. This species grows to about 1⁄2 inch (1 centimeter) across.
Many species of tarantula live in burrows in the ground. But some tarantulas dig deeper than others.
Australian tarantulas, also called whistling or barking spiders, live in hot areas. They make a noise that sounds like whistling or barking when disturbed. These tarantulas dig burrows that are 1 to 3 feet (0.3 to 0.9 meter) deep. That far under the ground, it is cool and damp. Australian tarantulas will sometimes cover the opening of their burrow with silk to keep the moisture in. They may also build a mound of soil around the burrow entrance, which they cover with silk. The silk collects dew and raindrops for the spider to drink. The mound also keeps water from flooding the burrow.
King baboon tarantulas also dig deep burrows. Their burrows are more than 2 feet (0.6 meters) deep. These large tarantulas live in the grasslands of east-central Africa.
Cobalt blue tarantulas of Southeast Asia also dig large tunnels in the floor of the tropical forest.
Tarantulas must face a number of dangerous enemies. Birds, frogs and toads, lizards, snakes, and skunks and certain other mammals all dine on tarantulas. Some insects also prey on tarantulas.
One well-known enemy of the tarantula is the Pepsis wasp, often called the tarantula hawk. This wasp uses a tarantula as a kind of nursery and cafeteria for its young.
An adult female Pepsis wasp attacks and stings a tarantula. The wasp’s venom paralyzes the tarantula but does not kill it. The wasp lays an egg on the spider’s body. An undeveloped form of the wasp, called a larva, hatches from the egg. The larva then burrows into the spider and begins to eat it. The larva feeds on the tarantula until the tarantula dies. Slowly, the larva turns into an adult form of a wasp.
Several other types of wasps prey on tarantulas or other spiders in this way.
A tarantula’s skeleton is on the outside of its body. This type of skeleton is called an exoskeleton.
An exoskeleton cannot grow larger. So, when a tarantula’s insides get too big for its exoskeleton, the exoskeleton splits and falls away. The spider then develops a new exoskeleton. This process is called molting. Young spiders molt often as they grow. Adult females molt about once a year. Adult males rarely molt.
Your pet tarantula usually will stop eating a few days before it begins molting. The exoskeleton will split around the edge of the body and separate from the body. The spider then has to pull its legs carefully out of the old exoskeleton.
Do not touch your spider during its molt. Also, do not put any food—and especially no live insects—into your spider’s container when it is molting. A molting spider is defenseless and fragile.
Tarantulas do not like getting wet. They can sense even tiny amounts of water with their legs. They try to avoid getting into water above their head. Nevertheless, arboreal tarantulas sometimes accidentally fall into ponds and streams from overhanging tree branches.
A tarantula will usually float if it falls into water. Tiny air bubbles trapped between the setae on a tarantula’s body and legs keep it afloat. The tarantula can then swim to dry land by paddling with its front pair of legs.
Tarantulas are also waterproof. When they climb out of the water, they are perfectly dry.
Many kinds of tarantulas can make noises when they are frightened or upset. This noise is called stridulating. Stridulating sounds like hissing. Different species of tarantulas make stridulating noises by rubbing different parts of their body against one another. The body parts used for stridulating include the legs, chelicerae, and pedipalps.
Tarantulas often stridulate while rising up on their back legs. They strike with their front legs and show their fangs. Often, these actions frighten an attacker away.
Many people think tarantulas are scary and creepy. So, it is not surprising that filmmakers have used tarantulas in many horror, adventure, and even comedy films. Many science-fiction films, such as Tarantula (1955), have also featured large, scary spiders.
Mexican redknee tarantulas were used in the adventure film Raiders of the Lost Ark (1981). In one scene, at least 40 of these tarantulas swarmed over actors Harrison Ford and Alfred Molina. The people who handle the tarantulas used in such modern movies as Raiders of the Lost Ark are called spider wranglers. These wranglers work to get spiders to do the things the director desires. For example, spider wranglers might use thin vibrating wires, blow dryers, or slippery furniture-polish to help guide a spider’s movements. As is often the case with scenes involving animals, sometimes a director must shoot a scene many times to finally catch a tarantula “following direction” on film.
The most common problems in pet tarantulas are dehydration and wounds. In a tarantula, signs of dehydration—the loss of water from the body—include slow movement and a shriveled appearance.
Wounds are serious problems for tarantulas because their hemolymph (spider blood) does not clot (thicken) and stop the bleeding as human blood usually does. One possible treatment for a tarantula wound is to brush on something that will cover the wound and then dry hard, like the “liquid bandages” sold in drugstores for people. For a wound to a spider’s abdomen, brush the wounded area with Superglue. To treat a tarantula wound, ask an adult for help.
Tarantulas are also very easily injured while they are molting. If a tarantula gets stuck in its old exoskeleton during a molt, it could die.
You are responsible for providing your tarantula with good food and a safe, clean, comfortable living space. You have to make sure to keep your tarantula’s cage at the right temperature and humidity. Make sure the air in your tarantula’s container is moist enough for your type of tarantula. Species that are native to desert areas need less moisture than species from rain-forest environments.
Protect your tarantula by handling it very carefully—or not at all. If your tarantula is injured, you must get an adult to help you treat the injury. Guard your pet against falls. Falling even a few feet can be dangerous for a tarantula.
Your female tarantula can live for 20 years or more, so be ready to make a long-lasting commitment to her care. If you can no longer care for your tarantula, find it a new home where it will be well cared for. You must not turn it loose.