10 Surprising Tarantula Facts

Tarantulas have an image problem — most of what people assume about them comes from horror movies rather than biology. Here are ten facts that paint a very different picture. For care basics, see our full Tarantula care guide, and for what's actually happening when one goes still and stops eating, our guide to invertebrate molting.

1. Females can live decades longer than males. Some female tarantulas live 20 to 30 years in captivity, while males of the same species often live only 5 to 7 years, frequently dying within months of reaching maturity.

2. Their blood is blue, not red. Like other arthropods, tarantulas use copper-based hemocyanin to carry oxygen instead of the iron-based hemoglobin found in vertebrates, which gives their blood a blue tint.

3. They "hear" through vibrations, not ears. Tarantulas lack ears entirely and instead sense their environment through tiny sensory hairs on their legs that detect vibrations in the ground and air.

4. Their main defense usually isn't biting. Many New World tarantula species kick urticating hairs from their abdomen when threatened, which cause intense itching, rather than relying on their bite as a first line of defense.

5. All tarantulas produce silk, not just web-builders. Even species that don't spin prey-catching webs use silk to line burrows, wrap egg sacs, and create drop-lines, silk plays a role in nearly every tarantula species' life regardless of hunting style.

6. Some species can go over a year without eating. Tarantulas have remarkably slow metabolisms, and healthy adults — especially during premolt — can fast for extraordinarily long stretches without harm.

7. The largest species by mass has a leg span near a foot. The Goliath birdeater, native to South America, is among the largest tarantulas in the world, with a leg span that can approach 11 to 12 inches.

8. Despite the name, they rarely eat birds. "Bird-eating" spiders got their name from a rare historical account, but their actual diet is overwhelmingly insects, and occasionally small vertebrates like lizards or frogs for the largest species.

9. A short fall can be more dangerous than a bite. A tarantula's exoskeleton is surprisingly fragile against impact, and a fall from even a modest height — like off a keeper's hand — can rupture the abdomen and be fatal, making drop injuries one of the leading causes of death in captivity.

10. Molting lets them regenerate lost limbs. A tarantula that loses a leg to injury or a failed molt can regrow it over subsequent molts, gradually restoring it to near-normal size and function.

Which of these surprised you the most? I would love to hear in the comments.

Sources