To the Critter Corner Directory.

Introduction

In the fall of 1996, I received a box from the Carolina Biological Supply Company in Burlington, North Carolina. The custodians brought the box to me immediately because the words "LIVE ANIMAL" were stamped boldly upon it and the office was anxious to be rid of it! My biology students were eager to explore the contents so we opened the box immediately and set up a habitat for our new classroom tarantula. The spider came to us rather thin but was an eager eater from day one. We gave it two large juicy crickets which it grabbed quickly. Today (fall 1997) it is a plump, healthy spider that has already molted once. Our spider is a South American rosy tarantula; however, there are others that are excellent in a classroom.

Scientific Name

brown tarantula - Aphonopelma sp.
pink-toed tarantula - Avicularia avicularia
South American rosy tarantula - Grammostola sp.

General Physical Description

Tarantulas are large, hairy spiders. The rosy-haired tarantula is soft dark brown with interspersed pink hairs that are beautiful in the light. Our Rosy has a cephalothorax-abdomen length of about 6 cm. Adding the four pair of hairy jointed legs brings the total length to about 8 cm. There are two pairs of spinnerets at the end of the abdomen. (When we received Rosy, she impressed us by spinning "silk" around her cricket prey on the very first day.) As well as the four pair of legs there is a pair of pedipalps in the front of the cephalothorax. On the underside of the tarantula is a most impressive pair of fangs! Though no spider bite is particularly pleasant, the tarantula is not much more poisonous to humans than a bee. However, if someone is allergic to bees, they might be sensitive to spider venom.

Behavior

Tarantulas are nocturnal so they might be rather quiet during the day. When given a cricket, the tarantula grabs it with legs and fangs and injects poison to immobilize the insect. Enzymes are secreted to begin the external digestion. Then the spider sort of sucks out the "juice" of the insect. Sometimes the spider will spin a web over the remains. When handled, some American tarantulas will "throw" special hairs on their abdomen. There are called "urticating" hairs because they have little barbs and can imbed in soft tissue. This is very helpful to the tarantula if a predator tries to have it for lunch! The spider can just throw these hairs into the eyes of the predator! However, our docile Rosy does not have the ability to throw hairs. Female tarantulas molt (shed their skins). This is a most remarkable event. Students will look into the cage and be sure that the spider has cloned itself! The molting is a perfect replica of the spider.

Spiders molt in order to grow. They shed one exoskeleton and then a new larger one hardens around the spider. When ready to molt, the spider stops eating for a few days. Then it lies on its back and literally steps out of its old exoskeleton. When you see the spider on its back, it is not dead - just molting!

Reproduction

It is unlikely that you will breed spiders in captivity, but students will be interested in how spiders mate and reproduce. The male has special palps on his pedipalps. He takes sperm from his genitals onto his palps and inserts the sperm into the female's genitalia - a slit on the ventral side of the abdomen. Males only live a few months after mating. (Females can live up to 25 years!) The female will deposit the eggs and perhaps spin a web-type nest to protect them until they hatch - but this varies with the species.

Classroom Habitat

A simple aquarium is adequate. I use a 10 gallon aquarium with a fine screen lid. Spiders need good air exchange because they generally do not like humidity. However, our South American spider prefers a little more humidity than some. A little light misting is nice, occasionally. I put gravel on the bottom. Vermiculite will work, too. Rosy is a burrowing spider so I have provided her with a hiding place by building a nice rock cave. There is also a small dish of water in her cage. Tarantulas do fine at room temperature. Rosy prefers a temperature during the day that is a bit warmer than our air-conditioned school. If your classroom gets colder, you might like to provide a heater under the cage or under the gravel.

Food and Feeding Schedule

Tarantulas do fine by eating about twice a week. I put in 2-3 crickets twice a week and remove any that are not eaten during the day. It is best to try and feed them a variety of insects. Your students can help with this. They can become very good at bringing beetles and other interesting appetizers! Some tarantulas will even eat millipedes.

Handling Tips

Tarantulas can actually be handled if you are careful. Most of the care needs to be taken so that you don't hurt the tarantula! With a docile tarantula (the South American rosy tarantula is one of the best), you just put your flat hand in front of the spider and gently tickle the back legs until the spider crawls onto your hand. If you are very careful, you can grab very gently with your thumb and finger between the second and third pair of legs where they join to the body. If it is still too active, it will probably slow down if you cup both hands over it. We don't handle Rosy very much. Mainly, we like to observe her behavior while she is in her cage.