From termite mounds and caterpillar cocoons to the elaborate nests of social birds and the deadly traps of spiders, the constructions of the animal world can amaze and at times even rival our own feats of engineering. But how do creatures with such small brains build these complex structures? What drives them to do it? In this fascinating volume, Mike Hansell looks at the extraordinary structures that animals build--whether homes, traps, or courtship displays--and reveals what science can tell us about this incredible behavior. We look at wasp's nests, leaf-cutting ants, caddis flies and amoebae, and even the extraordinary bower bird, who seduces his mate with a decorated pile of twigs, baubles, feathers, and berries. We discover how some animals produce their own building materials, such as the silk secreted by spiders to weave an array of different web and traps, or the glue some insects produce to hold their buildings together. And we learn how a vast colony of social insects can create nests which may penetrate up to twenty feet into the ground and house millions of individuals--all built by tiny-brained animals repeating many simple actions as they roam randomly around the structure. Hansell also sheds light on how animal buildings have evolved over time, how insect societies emerged, how animals can alter their wider habitat, and even whether some animals have an aesthetic sense. Built by Animals offers a colorful account of a facet of animal behavior that will delight anyone interested in the natural world.