[en español]

KidZone Animal Facts
Red-Rump Tarantulas

Red-Rump Tarantula (early morning in Belize)
Photo by CameliaTWU, CC BY-NC-ND 2.0

Contributed by Leanne Guenther

Red-Rump Tarantulas or Brachypelma vagans are members of the Arthropod phylum, which is the scientific name for animals like insects, spiders and lobsters.  They are also members of the Araneae order, which is the scientific name for spiders.

Red-Rump Tarantulas are 4 or 5 inches across (including their legs) but some females can get as large as 6 inches. The males are smaller than the females. Sometimes the female spiders eat their boyfriends -- yikes!

Red-Rump Tarantula females lay about 300 eggs in a silk cocoon called an "egg sac". She keeps the egg sac in her burrow, protecting it from predators until the eggs hatch. Once they hatch, the spiderlings (baby tarantulas) leave the burrow going out to start life on their own - mom's job is done and she gets her burrow back to herself.

When they are young, the spiderlings are brown. Once they are adults the males and females get red hairs on their abdomen (which is why they are called "red-rump" tarantulas). They look quite similar but the males are a little bit brighter red and the females are a bit larger.

Red-Rump Tarantulas live solitary lives, mainly in Mexico but also in some parts of Central America.  Most spiders spin webs to live on and catch prey but not tarantulas -- they live in burrows that they dig into the ground.  Like other spiders, they do spin silk from their abdomen, but they use this silk to line the inside of their burrows not to catch prey.

Red-Rump Tarantulas sleep in their burrows during the day and then, at night, come out to hunt. They pounce on their prey and quickly pierce them with venomous fangs like ice-picks. They inject digestive juices into their prey that (quite quickly) turns them into a sort of soup that the spider slurps up.

When feeling threatened, the Red-Rump Tarantula rears up, raising its front legs to show off their threatening fangs. If this doesn't scare off an enemy, the next line of defense the tarantula uses is to flick itchy little hairs at the enemy using their legs. These hairs are called "urticating hairs" and grow on the tarantula's abdomen. It's very similar to what a porcupine does with its quills. The urticating hairs have a hook at the end that itches and irritates the skin and possibly eyes of the enemy. Over time, these hairs can even work themselves deeper into soft flesh.

It's interesting to note that even something the size of a human can have bad discomfort from a tarantula's urticating hairs. Red-Rump Tarantulas are often kept as pets and there have been cases where people get the hairs in their eyes which can cause extreme pain and requires an immediate visit to an eye-doctor to prevent complications.

One of the most fascinating things about red-rump tarantulas is that they live for so long -- a female can live for nearly 20 years. The male's life-span is closer to 5 years (if he doesn't get eaten by one of the females before then!)

Red-Rump Tarantula Summary:

Scientific name (genus and species)Brachypelma vagans

Phylum:  Arthropod
:  Arachnida
Size:  6 inch leg span (males are smaller)

Habitat: lives mainly in Mexico; digs a burrow in the ground where it sleeps during the day; lines its burrow with silk produced from its abdomen.

Food: hunts insects and sometimes even small mammals and lizards

Weapons: venomous fangs like ice picks pierce prey; digestive juices injected into prey to dissolve them; hunts at night

Defenses: itchy, urticating hairs on abdomen – uses its legs to fling these hairs at enemies; underground burrow to hide from predators during day

Predators: birds; snakes, spider wasps

Red-Rump Tarantula fact sheet


Facts Card Printable Template:




Scientific Classification:

Kingdom:  Animalia (Animals)

Phylum:  Arthropoda (Arthropods - insects, crustaceans and spiders)

Subphylum:  Chelicerata (arthropods with chelicerae - mouthparts with fangs or claws)

Class:  Arachnida (arthropods with eight legs)

Order:  Araneae (Spiders)

Family:  Theraphosidae (large and hairy spiders)

Genus:  Brachypelma (tarantulas in Mexico and Central America)

Species:  B. vagans (Red-Rump Tarantula)

Vocabulary Words:

Abdomen:  The back end of the spider, it contains the spider's heart, lungs and silk glands.

Arthropod:  Arthropods are an animal phylum that includes cold-blooded animals with segmented bodies, jointed legs and an exoskeleton.  This class includes spiders like the tarantula and larger animals like the crab.  Learn more about arthropods.

Burrow:  A hole dug in the ground by small animals, like tarantulas, for protection while sleeping.

Chelicerae:  Chelicerae are the mouth parts of certain animals including spiders and scorpions. These mouth parts can be moved and end in either a claw or a fang, depending on the animal. Spiders have fang chilicerae while scorpions have claw chelicerae.

Egg sac:  Cocoon like cluster of silk the female spider lays its eggs in. Unlike most spiders, red-rump tarantula females guard their egg sac to protect the eggs.

Exoskeleton:  The hard outer shell of some animals, especially insects.  Insects and spiders do not have any bones inside of them, instead they have a hard shell that holds the body together.

Fang:  Fangs are the biting mouthparts of spiders. The tip of the fang opens to release poison into the prey.

Molt:  Molting is the process by which spiders shed their exoskeleton and grow a new one. Red-rump tarantulas molt frequently as spiderlings but only about once a year once they are adults.

Pedipalps:  Pedipalps are the two appendages on the front of a spider's head. Some spiders seem to have ten legs and not eight, because these pedipalps look like an extra pair of legs.

Predators:  Animals that are trying to kill and eat the tarantula.  A red-rump tarantula's main predators are snakes, birds and spider wasps.

Prey:  Animals that the tarantula is trying to kill and eat.

Spiderlings: Newly hatched, baby spiders.

Spinneret:  Spinnerets are the small organs at the back of a spider's abdomen that release silk from the silk glands. Spiders often use their legs to pull the silk from the spinnerets which is why it sometimes looks like the silk is coming from the legs.

Urticating hairs:  Urticating hairs grow on the abdomen of tarantulas. They use their legs to fling these hooked or barbed hairs at potential enemies when they are feeling threatened.

Venom:  Poisonous substance produced in a spider's poison glands which is injected into prey through holes in the spider's fangs.