The Goliath bird-eating spider is thought to be the largest spider in the world because of its large size. In this video, British naturalist Steve Backshall handles one of the massive spiders in the jungles of South America. The arachnid has fangs that are nearly as large as a cheetah's claws. The spiders, which can grow to a foot in size, were named after explorers witnessed one eating a hummingbird. However, the spider doesn't normally eat birds. It has been seen mainly feeding on rodents, insects, lizards and bats.