Underwater architects: Nest-building in cichlids reveals more than hardwired instinct

We associate nests with shelter, warmth, and a safe retreat—and usually picture a bird's nest made out of twigs, grass and feathers. Yet many other animals take advantage of such refuges, with nests being built by a diversity of species ranging from termites to great apes, which impress with their hugely varied forms and the wide array of materials used to construct them.