Tarantulas Rarely Bite (And Other Facts About the Friendly Spiders)

Why Tarantulas Should Inspire Fascination, Not Fear

Tarantula
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Tarantulas are the giants of the spider world, well known for their conspicuous size and their common appearance in movies as evil forces. Many people flinch in horror at the sight of them. These big, beefy spiders strike fear in the hearts of arachnophobes everywhere, but in fact, tarantulas are some of the least aggressive and dangerous spiders around.

1. Tarantulas are quite docile and rarely bite people

A tarantula bite to a human is typically no worse than a bee sting in terms of toxicity. Symptoms from most species range from local pain and swelling to stiffness of joints. However, tarantula bites can be lethal to birds and some mammals.

2. Tarantulas defend themselves by throwing needle-like hairs at their attackers

If a tarantula does feel threatened, it uses its hind legs to scrape barbed hairs (called urticating or stinging hairs) from its abdomen and flick them in the direction of the threat. You'll know it if they hit you, too, because they cause a nasty, irritating rash. Some people may even suffer a serious allergic reaction as a result, especially if the hairs come in contact with their eyes. The tarantula pays a price, too—it winds up with a noticeable bald spot on its belly.

3. Female tarantulas can live 30 years or longer in the wild

Female tarantulas are famously long-lived. In captivity, some species have been known to live for over 30 years.

Males, on the other hand, don't live very long once they reach sexual maturity, with a lifespan of just three to 10 years on average. In fact, males don't even molt once they reach maturity.

4. Tarantulas come in a wide variety of colors, shapes, and sizes

Colorful tarantulas that can be kept as pets include the Mexican red knee tarantula (Brachypelma smithi), the Chilean rose tarantula (Grammastola rosea), and the pink-toed tarantula (Aricularia avicularia).

The largest tarantula known on Earth is the goliath bird eater (Theraphosa blondi), which is fairly fast-growing and can reach a weight of four ounces and a leg span of nine inches. The smallest is the endangered spruce-fir moss spider (Microhexura montivaga); it grows to a maximum size of one-fifteenth of an inch, or about the size of a BB pellet.

5. Tarantulas ambush small prey at night

Tarantulas don't use webs to capture prey; instead, they do it the hard way—by hunting on foot. These stealthy hunters sneak up on their prey in the dark of night. Smaller tarantulas eat insects, while some of the larger species hunt frogs, mice, and even birds. Like other spiders, tarantulas paralyze their prey with venom, then use digestive enzymes to turn their meal into a soupy liquid.

Tarantula venom is made up of a species-specific mix of salts, amino acids, neurotransmitters, polyamines, peptides, proteins, and enzymes. Because these toxins are hugely varied across species, they have become a target for scientific research for potential medical uses.

6. A fall can be fatal to a tarantula

Tarantulas are rather thin-skinned creatures, particularly around the abdomen. Even a fall from a height of less than a foot can cause a deadly rupture of the exoskeleton. The heaviest species are the most susceptible to damage from drops.

For this reason, handling a tarantula is never recommended. It's easy for you to get spooked—or, even more likely, for the tarantula to get spooked. What would you do if a huge, hairy spider started squirming in your hand? You'd probably drop it, and quickly.

If you must handle a tarantula, either let the animal walk onto your hand or pick the spider up directly with cupped hands. Never handle a tarantula during or near the time of her molt, an annual period that can last up to a month.

7. Tarantulas have retractable claws on each leg, like cats

Since falls can be so dangerous for tarantulas, it's important for them to get a good grip when they're climbing. Though most tarantulas tend to stay on the ground, some species are arboreal, meaning they climb trees and other objects. By extending special claws at the end of each leg, a tarantula can get a better grasp of whatever surface it is attempting to scale.

For this reason, it is best to avoid mesh tops for tarantula tanks, because the spider's claws can get caught in them.

8. Though tarantulas don't spin webs, they do use silk

Like all spiders, tarantulas produce silk, and they put it to use in clever ways. Females use silk to decorate the interior of their underground burrows, and the material is thought to strengthen the earthen walls. Males weave silken mats on which to lay their sperm.

Females encase their eggs in silken cocoons. Tarantulas also use silk trap lines near their burrows to alert themselves to potential prey, or to the approach of predators. Scientists have discovered that tarantulas can produce silk with their feet in addition to using spinnerets as other spiders do.

9. Most tarantulas wander around during the summer months

During the warmest months of the year, sexually mature males begin their quest to find a mate. Most tarantula encounters occur during this period, as males often disregard their own safety and wander around during daylight hours.

Should he find a burrowing female, a male tarantula will tap the ground with his legs, politely announcing his presence. This suitor is a good source of much-needed protein for the female, and she may try to eat him once he's presented her with his sperm.

10. Tarantulas can regenerate lost legs

Because tarantulas molt throughout their lives, replacing their exoskeletons as they grow, they have the ability to repair any damage they've sustained. Should a tarantula lose a leg, a new one will reappear the next time it molts. Depending on the tarantula's age and the length of time before its next molt, the regenerated leg may not be quite as long as the one it lost. Over successive molts, the leg will gradually get longer until it reaches its normal size again. Tarantulas will sometimes eat their detached legs as a way to recycle protein.