What Is a Tarantula?

Tarantulas are large, hairy spiders that have captured people’s imaginations for centuries. While tarantulas may look intimidating, they are generally not dangerous to humans. Let’s explore what exactly a tarantula is and what makes these spiders so fascinating.

An Overview of Tarantulas

Tarantulas belong to the Theraphosidae family of spiders, which includes over 1,000 species found in tropical and subtropical regions around the world. Some key facts about tarantulas:

  • They are characterized by their large, hairy bodies and legs. Their leg span can reach over 10 inches across in some species.
  • Most tarantulas are terrestrial, living in burrows on the ground, but some tropical species are arboreal, living in trees.
  • They have eight eyes, but rely heavily on vibrations and their sense of touch to navigate their environments.
  • Tarantulas are invertivores, meaning they eat other invertebrates like insects, smaller spiders, and sometimes even small reptiles, birds, or mammals.
  • While all tarantulas are venomous, most species have venom that only causes mild pain and irritation in humans. None are known to be fatally dangerous.
  • Tarantulas shed their exoskeletons periodically as they grow, a process called molting. Young tarantulas may molt once every few months.
  • Females can live 15-30 years in captivity, while males tend to have shorter lifespans of 5-10 years.

So in essence, tarantulas are large, long-lived spiders with a notorious reputation that overshadows their relatively harmless nature. Next, let’s go over some key characteristics that define these fascinating arachnids.

What Makes a Spider a Tarantula?

Tarantulas have a unique set of physical and behavioral traits that set them apart from other spiders. Here are some of their defining features:

Size and Hair

  • Tarantulas are some of the largest spiders in the world. Leg spans range from 2-10 inches across depending on species, with bodies 1-2 inches in diameter.
  • They are covered in dense hairs called setae that range in color from brown to black to reddish depending on species. The hairs provide sensory information about their surroundings.
  • The setae also give tarantulas their signature fuzzy, fluffy appearance that reveals their relation to other New World terrestrial tarantulas.

Fangs and Venom

  • All tarantulas have two fangs used to inject venom into prey. The fangs are short, only about 1/4 inch long, but their venom is quite potent.
  • Their venom is designed to paralyze and liquefy insect prey but can cause pain and irritation in humans if bitten. Some New World species can cause more severe reactions.
  • Old World tarantulas from Europe, Asia, and Africa tend to have more potent venom. No tarantulas are known to be medically significant or fatal to healthy adults, however.


  • Tarantulas have eight eyes, but they don’t rely on eyesight to hunt. Instead, they use vibrations sensed through the hairs on their bodies.
  • Their eyes are simple and can only detect changes in light versus dense shapes. Four smaller eyes point forward and two larger principal eyes point to each side.
  • Due to their poor eyesight, tarantulas’ best defense against predators is hiding in their burrows.

Growth and Molting

  • Young tarantulas go through a molting process every few months as they grow. Adults only molt annually or less.
  • During a molt, they shed their exoskeleton and grow a new one that will accommodate their larger body size. They are vulnerable during this time until the new exoskeleton hardens.
  • Tarantulas must molt in order to grow. If a molt goes wrong and the spider can’t free itself from its old exoskeleton, it will die.

Sexual Dimorphism

  • Male and female tarantulas look quite different once they reach adulthood. This is called sexual dimorphism.
  • Males have smaller bodies but longer legs and pedipalps (mouth appendages). The pedipalps contain the sexual organs.
  • Females are bulkier with shorter legs. They have a large opisthosoma (abdomen) to accommodate eggs.
  • Males live shorter lives than females since their sole purpose after maturing is finding a mate. Females can live double or triple the lifespan of males.

The combination of these traits – large hairy bodies, potent venom, poor eyesight, molting habit, and sexual differences – is what defines the tarantula. Next we’ll look closer at tarantula behavior.

The Behavior of Tarantulas

Much of tarantula behavior comes down to survival in their natural environments:

Hunting and Feeding

  • Tarantulas are sit-and-wait predators rather than active hunters. They spend most time in their burrows and strike when prey wanders close.
  • They use their sensitive hairs to detect vibrations of potential prey. Then they pounce and deliver a venomous bite to paralyze the prey before ingesting it.
  • They feed primarily on insects but will eat other available invertebrates, even small vertebrates in some cases.

Defense and Biting

  • A tarantula’s first line of defense is hiding in its burrow. If threatened, it may hiss by rubbing its legs together and scraping hair off its abdomen.
  • If further provoked, it will assume a threat posture – rearing up and presenting its fangs. This is meant to scare off predators.
  • Biting is a last resort and done reluctantly since the tarantula may damage its fangs. The bite is not pleasant but won’t kill a healthy human.

Habitat and Web Building

  • Most tarantulas live in self-made burrows underground or in tree cavities and root masses for tropical species.
  • Some lineages make silk webbing at the entrance to their burrow or in their nests, but tarantulas don’t construct webs to catch prey.
  • The silk aids in stabilizing the burrow entrance and allowing the tarantula to sense vibrations from potential threats or prey.

Breeding and Life Cycle

  • When males reach maturity, they wander in search of female burrows, sparring with other males along the way.
  • Successful males stimulate the female and deposit sperm on her abdomen via the pedipalps. The female later uses the sperm to fertilize her eggs.
  • Females lay eggs one sac at a time, with 100-1000 eggs per sac depending on species. The mother guards the sac until hatching.
  • Young spiderlings stay with the mother for a period before dispersing. They go through multiple molts as juveniles before reaching maturity after 1-2 years.

This covers some of the key elements of how tarantulas behave in nature. Now let’s go over what makes tarantulas unique in more detail.

Unique Traits and Adaptations

Tarantulas stand out from other spiders in the animal kingdom due to their unusual mix of traits. Here are some of their most distinctive adaptations:

Hair Flicking Defense

Tarantulas have evolved a unique defense mechanism – they use their hind legs to flick irritating hairs from their abdomens at threats. These tiny hairs cause itching, pain, and disorientation. This allows the tarantula to escape while the threat is distracted.

Pedipalps for Mating

Male tarantulas have pedipalps that act as short ‘legs’ near their mouths. These pedipalps are adapted to transferring sperm – males insert their pedipalps into the female’s reproductive organs to fertilize her eggs.

Venom Immunity

Tarantulas have immunity to their own venom, so they can envenomate prey without harming themselves. Their venom only activates when mixed with blood, so it remains harmless in their own bodies.

Vibration Sensing

Tarantulas’ sensitive body hairs allow them to detect even the faintest vibrations from prey animals through direct contact with the ground. This makes up for their poor eyesight.

Abdominal Spiracles

Tarantulas have evolved a respiratory system with spiracles – external openings that allow air exchange – along their ventral abdomen rather than internal book lungs like other spiders. This improves oxygen circulation.

These adaptations allow tarantulas to survive and thrive in their environments around the world. Next, let’s look at tarantula family trees.

Types of Tarantulas

There are numerous tarantula species found across the tropical and subtropical regions of the world. They belong to the same infraorder (Mygalomorphae), but there are distinctions between Old World and New World groups.

Old World Tarantulas

Old World tarantulas originate from Europe, Asia, Africa and Australia. Some examples include:

  • Cobalt Blue Tarantula – One of the most popular species in the pet trade known for its electric blue legs. Native to Thailand and Malaysia.
  • Singapore Blue Tarantula – Another popular electric blue species from Southeast Asia named Cyriopagopus lividus.
  • Indian Ornamental Tarantula – A docile black and white burrowing tarantula native to Northern India.
  • King Baboon Spider – An aggressive African tarantula named for its hairy legs that it rubs together to make a hissing sound.

New World Tarantulas

New World tarantulas come from North America, Central America, and South America. Some well-known examples:

  • Chilean Rose Tarantula – Likely the most common pet tarantula that was imported heavily in the 1990s. Docile and easy to care for.
  • Mexican Redrump Tarantula – Skittish species from Mexico with distinct orange and black banding on its legs and abdomen.
  • Brazilian Black Tarantula – Large black burrower native to Brazil that is slower moving yet aggressive. Grows up to 8 inches legspan.
  • Chaco Golden Knee Tarantula – Beautiful docile species from Bolivia coveted for its orange and blackbanded legs.

This covers some of the most popular tarantulas from both hemispheres, but there are many more regional species across the tropics. Next we’ll look at tarantulas as pets.

Tarantulas as Pets

The exotic appearance of tarantulas has captivated people for decades, making these spiders popular pets. What should know before getting a pet tarantula?

Selecting the Right Species

Some docile species that make good pets include:

  • Chilean Rose – Easygoing and acclimates to handling.
  • Curly Hair – Moderately easy to care for and docile.
  • Mexican Redleg – Skittish but attractive and fairly low-maintenance.

Avoid Old World species like Cobalt Blues as pets – they tend to be nervous, fast, and prone to biting.

Housing Your Tarantula

Pet tarantulas need:

  • An adequately sized terrarium – 5-10 gallons for most species. Old World arboreal species need tall enclosures.
  • Substrate material like coconut fiber to allow burrowing. Provide hiding places like caves too.
  • A small dish of fresh water and elevated dish of live prey insects like crickets.
  • The proper temperature range – typically 70-85° Fahrenheit.

Handling Precautions

It’s possible to handle your tarantula but do so carefully:

  • Always support their underside not their legs – their legs can detach if pulled on.
  • Keep handling brief and infrequent, as it’s stressful for them.
  • Never handle if aggressive, hungry, or in premolt.
  • Keep calm and avoid fast movements that may illicit a defensive bite.

Lifespan as Pets

With proper care, female tarantulas can live 15-30 years in captivity. Males tend to have shorter lifespans of 5-10 years. Proper feeding, humidity, and molting conditions help ensure a long healthy life.

Tarantulas can make fascinating pets for the right owner willing to provide good care. Next, we’ll look at some myths and facts about tarantulas.

Tarantula Myths Versus Facts

Tarantulas suffer from many misconceptions that make people fear them more than necessary. Let’s clear up some common myths.

Myth: Tarantulas Are Aggressive

Fact: Most species are quite docile and will only bite as an absolute last resort. They prefer to flee threats. Some skittish species may flick urticating hairs when disturbed.

Myth: Tarantula Bites Are Deadly

Fact: No tarantula species has venom potent enough to kill a healthy human. At most the bite causes pain, muscle spasms, and sensitivity. Only those with allergies risk serious reactions.

Myth: Tarantulas Live in Colonies

Fact: Tarantulas are solitary – the only time they interact are brief breeding encounters between mature males and females. They don’t build collaborative webs either.

Myth: Tarantulas Can Jump Long Distances

Fact:Tarantulas pounce but can’t jump more than a few inches. They only fall from vertical surfaces if desperate to escape a threat. They don’t intentionally leap at threats or prey.

Myth: Tarantulas Infest Houses

Fact: Tarantulas avoid humans and stay in their natural habitats away from major disturbances. They only enter manmade spaces on accident.

The truth is, tarantulas want little to do with humans, and their fearsome image is overexaggerated. Their docile nature when unprovoked shows they only bite in self-defense.

Why Are People Fascinated By Tarantulas?

So why are people so enthralled by these spiders if most of the fears about them are exaggerated? Here are some reasons tarantulas captivate people:

  • Their imposing size and hairy appearance catch people’s interest – they look like mini monsters!
  • Their role in nature as stealthy ambush predators makes their hunting behavior interesting to observe.
  • Their longevity, especially among female specimens, is extraordinary compared to other spiders.
  • Their periodic molting and their extreme morphological changes from spiderlings to maturity are fascinating natural processes to witness.
  • Their docile nature in captivity combined with their exotic look and reputation makes them alluring pets.
  • The variety of regional color forms, body types, and behaviors across different tarantula species provides endless opportunities for study and collection.

Overall, tarantulas’ combination of being gentle giants with a ferocious image gives them an air of mystery and awe that intrigues arachnid enthusiasts and general nature lovers alike. Their nuanced traits reveal there’s much more to these spiders than myths suggest.

Frequently Asked Questions About Tarantulas

Here are answers to some common questions people have about tarantulas:

Q: How long do tarantulas live?

A: Females can live 15-30 years in captivity. Male lifespans are shorter at 5-10 years. With good care, tarantulas are among the longest lived spiders.

Q: Do tarantulas make good pets?

A: For the right owner, tarantulas can make great pets, especially docile species like the Chilean Rose. They require minimal handling and proper habitat conditions.

Q: Are pet tarantulas dangerous?

A: Pet tarantulas rarely bite and have mild venom that only causes irritation. Handling should be done carefully but they pose little danger overall. However, people with spider allergies should avoid them.

Q: What do tarantulas eat?

A: Tarantulas are carnivores that eat insects, other arthropods, small reptiles, mammals, or birds in some cases. Pet tarantulas eat live insects like crickets or mealworms.

Q: How big do tarantulas get?

A: Tarantula leg spans range from 2 inches to over 10 inches depending on species. Some have bodies over 2 inches wide. Females are larger than males in most species.

Q: Do tarantulas make webs?

A: They don’t make prey-catching webs. Some may make silk webbing around their burrow entrances to sense vibrations from intruders or prey.

Q: Are tarantulas hairy?

A: Yes, tarantulas are covered indense bristly hairs called setae that are used to protect themselves and sense their environment. The hairs contribute to their fuzzy, fluffy look.


While tarantulas look intimidating, they are mostly gentle creatures that only bite when threatened and play important roles as predators in their ecosystems. Their variety of behavioral and physiological adaptations provide a lifetime of fascination for arachnid enthusiasts. With the facts in hand, tarantulas can be appreciated for their nuanced nature rather than feared for myths about them. Their growing popularity as pets shows that for every person who shies away from their hairy legs, there is another intrigued to learn what tarantulas are really all about.