Darwin’s bark spider

Darwin’s bark spider is very small and yet constructs webs with anchor lines spanning rivers. Originally discovered in Madagascar in 2001, Darwin’s bark spider constructs webs that can span entire rivers! Its silk must be remarkably strong in order to bear the weight of its massive structures. Darwin’s bark spiders spin silk that is twice as strong as any other spider’s and ten times better than Kevlar, the substance used in bulletproof vests and bike frames.

The extra strong silk is what makes it possible for the spider to make anchor lines that are very long and can bear the weight of the central web, its contents, and the spider. Scientists counted 32 preys in a single web. These prey had not yet been wrapped up by the spider, meaning the web has a huge capacity for catching insects at any moment.

The extremely strong silk allows the Darwin’s bark spider to have a strategy no other spider can employ. It builds its webs in habitats other spiders are incapable of using, which means it can catch food without having to compete with other spiders. Their webs are built directly over streams, rivers and lakes.

The spiders were discovered in Madagascar’s Ranamofana National Park. After conducting tests and taking measurements of the spider’s silk scientists concluded it is the toughest biological material known to man. However, the scientists are not clear on how exactly the small spider constructs the anchor lines which span a stream or river and support the core web. One of the explanations given is that the spiders create a single silk strand and then swing themselves across a stream to the bank where the fix an anchor line, and then return to the other bank and do the same, sort of like Tarzan. Scientists believe that it is likely that there is even stronger silk out there that has yet to be found.