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River-Spanning Spider WebA river-spanning spider web dwarfs a park ranger in Madagascar in 2008. Made of the world's strongest known biological material, the web is the product of a new species, the Darwin's bark spider, which makes the world's largest webs of any single spider, new studies say.Zoologist Ingi Agnarsson and colleagues have found Darwin's bark spider webs as wide as 82 feet (25 meters)—about as long as two city buses.In Andasibe-Mantadia National Park (pictured), "the park rangers knew about them, and I think they've shown them to tourists for a while," said Agnarsson, of the University of Puerto Rico.But the Darwin's bark spider and its record-breaking webs were unknown to science until they were documented by the team, whose findings appear this week in the Journal of Arachnology and PLoS ONE.(Related: "Largest Web-Spinning Spider Found.")—Ker Than

Photograph courtesy Matjaz Kuntner