The world’s largest spider is the size of a dinner plate

Desertas wolf spider (Hogna ingens) (Credit: Luis Quinta/ Additional suggested reading: Charles Darwin: An Epiphany for the Muslims, A Catastrophe for the Christians

Source: BBC

You might think you would notice an eight-legged animal the size of a dinner plate, but in fact many of the world’s biggest spiders are easily overlooked.

In Europe, the Desertas wolf spider is only found in a single valley on the island of Madeira, Portugal. It is one of the world’s largest wolf spiders, with a body length of up to 1.6 inches (4cm) and distinctive black legs with white polka dots.

The family name conjures up fierce and predatory associations, and rightly so. Wolf spiders are named for their active hunting style. Instead of capturing prey in a web, these arachnids pounce on their meals.

Like any self-respecting legendary spider, it lives in a cave

However there are ways in which they differ from wolves. The spiders are solitary rather than pack hunters, so they ambush their prey or chase it down over a short distance. Also, they hunt millipedes, not mammals.

The most distinguishing characteristic of wolf spiders is the layout of their eyes. They have a row of four small ones, with two larger eyes above, topped by another two slightly smaller ones that boost their predatory senses. The Desertas wolf spider’s excellent eyesight allows it to hunt fast-moving beetles and even small lizards.

But conservationists are now keeping a keen eye on Europe’s biggest spider. It has been classified as “critically endangered” because its unique habitat is being overgrown with invasive grass.

A similarly remote location is home to one of Asia’s biggest spiders: the giant huntsman spider.

Giant huntsman spider (Heteropoda maxima) (Credit: Michal Cerny/Alamy Stock Photo)

Giant huntsman spider (Heteropoda maxima) (Credit: Michal Cerny/Alamy Stock Photo)

It has a leg span of up to 30 cm (1 foot), which has been championed as the world’s biggest. Like any self-respecting legendary spider, it lives in a cave.

In 2001, Peter Jäger discovered the species in a collection at the National Museum of Natural History in Paris, France, before heading out to Laos to visit its secluded habitat. Why it grows to such a significant size remains something of a mystery.

When approached, a king baboon spider rears up to expose its fangs and hisses loudly by rubbing its legs together

“A straightforward explanation is difficult,” says Jäger, “But I guess one reason in the case of H. maxima is certainly the cave-dwelling habit… prey is scarcer than outside, [meaning] growth is slower and this may result in bigger size.”

Unfortunately the media spotlight on the giant huntsman has had negative consequences. Jäger reports that its numbers are dwindling due to unregulated demand by the pet trade.

There are also large huntsman spiders in Australia. They usually hide under loose tree bark, but their long legs have also been spotted behind wall clocks and sun-visors in cars.

Since they prey on pests such as flies, they should be considered welcome guests. But their crab-like appearance, leg span of up to 6 inches (16cm) and ability to deliver a nasty nip when provoked can be alarming.

The huntsman might have the best pins, but the true heavyweight champions are the tarantulas.

One of Africa’s largest living spiders is the king baboon tarantula. It has a leg span of up to 8 inches (20cm) and is rusty red-brown in colour. In the wild it digs into the soil of grasslands, then constructs webs across its burrows to catch prey.

Hysterocrates hercules has a name which is bigger than the actual spider!

Their size makes them popular pets, but their temperament is less appealing. Their common name refers to the fact that baboons often eat them, and as a result they are highly defensive towards primates, including humans. When approached, a king baboon spider rears up to expose its fangs and hisses loudly by rubbing its legs together.

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Categories: Evolution

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