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Giant Huntsman Spider: World's Largest Spider By Leg Span

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An Australian huntsman spider.
Credit: Sandra Caldwell | Shutterstock

The giant huntsman spider is a species of huntsman spider (Sparassidae), a family of large, fast spiders with thousands of subspecies distributed in warm climates the world. These spiders hunt down their prey rather than catching it in silk webs — a habit that gives them their common name.

A giant huntsman was discovered in a cave in Laos in 2011 and with a leg span of up to 12 inches (30 centimeters), often described as being “the size of a dinner plate.” Only a few people in the world have seen this behemoth arachnid. This is the largest spider by diameter; the largest spider by weight is probably the goliath birdeater tarantula.

Huntsman spiders are also known as giant crab spiders because of their curious walking patterns and size. Because of their size, they are sometimes incorrectly identified as tarantulas. They are also sometimes confused with the brown recluse spider, though they are not nearly as poisonous. Its bite can be painful and cause swelling, but leaves no lasting damage and should be better in a few days.

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A huntsman spider walks along a brick windowsill.
Credit: kezza | Shutterstock

Appearance

Average huntsman spiders are about one inch (2.5 centimeters) long with a leg span of up to five inches (12.7 cm). Females have larger bodies while males have longer legs. Their long legs are typically grey or brown with banded legs. A common Florida species has black spots on legs that have grown erectile macroseta (hair), the only noticeable hair on the huntsman. Many species’ bodies have a flattened appearance, ideal for squeezing into tight places.

The huntsman spiders’ legs have twisted joints, which allow their legs to extend forward like a crab’s rather than bending vertically under the body, as is common for spiders. Their alignment allows them to move side-to-side, further explaining the giant crab nickname.

Distribution

The majority of huntsman species are native to Asia. They are also prevalent in Africa, Australia and South America. They live in some warm American states such as Florida, California and Texas, and it is presumed that they were introduced from Asia. It is sometimes said that they traveled from Asia in boxes of bananas, and because of that, they are sometimes called banana spiders. [Related: Face of 49-Million-Year-Old Spider Revealed in 3D]

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A huntsman spider's sharp fangs are used to inject venom into its prey.
Credit: Peter Waters | Shutterstock

Habits

The speedy huntsman can move up to a yard (almost 1 meter) a second. It typically lives under loose bark on trees, under rocks, in crevices and under foliage. Huntsman spiders, especially Australian species, are notorious for entering cars and houses. These spiders can be social, and dozens will sometimes sit together on dead trees or stumps.

The huntsman runs after or ambushes its prey, killing it with poison and strong mouthparts. It is considered a valuable spider because it eats cockroaches, in addition to other spiders and insects.

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An adult male huntsman spider compared to a penny.
Credit: Marie Knight/University of Florida.

Mating

Compared to other spider species that eat their mates, huntsman spiders are downright romantic. Their mating ritual can last for several hours and involves lengthy caresses and other demonstrations of interest. The male drums his palps against tree trunks before inserting them into the female to fertilize her eggs.

After mating, the female lays up to 200 eggs and encases them in a large, oval spun-silk sac. Some females carry the sac with them under their bodies, which severely restricts their movements. Others place the sac under a rock or piece of bark and stand over it, without eating, for up to three weeks. In both cases, females may become aggressive when guarding their egg sacs.

At birthing time, the mother may tear the egg sac open to help her spiderlings emerge. She’ll then stay with the babies for several weeks. Baby huntsmen are pale in color and darken with each molt.

Huntsman spiders can live for more than two years.

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