The Darwin’s bark spider is nothing special to look at — black, reddish-brown, and white, they resemble a bit of bark or a dry leaf, and even the larger females are less than an inch in size.
In fact, they’re so average-looking that it wasn’t until 2010 when they were first classified by scientists. Yet it’s pretty hard to imagine that it took that long to discover the enormous, durable webs they weave, stretching across rivers in Africa.
Biologist Igni Agnarsson first encountered the spider in the jungles of Madagascar, but their giant webs were no secret to park rangers in the Andasibe-Mantadia National Park. Researchers believe that these webs are among the largest known in the world.
They span up to 82 feet across a body of water, and the wheel-shaped orbs can be 30 square feet in size — large enough to capture its dinner of mayflies, damselflies, bees, or dragonflies. But the most impressive thing about these webs is not their size, but their strength.
Studies of the spider’s silk revealed it is the toughest biological material ever tested. Spider silk, in general, is known for its strength, but the Darwin bark spider’s silk is twice as robust as that of any other known spider, and ten times tougher than a similar-size piece of Kevlar.
The key to the silk’s sturdiness is its elasticity. When the spider initiates its web-building, it starts by secreting a long line of silk into the breeze, allowing it to float over a stream, river, or lake until it catches hold of something on the other side, forming a bridge.