The UK boasts the only professor of animal architecture in the world, Mike Hansell, lately of Glasgow University. He has studied from early in his career the habitat constructions of beavers, birds, rats, wood lice, shrimps and even dinosaurs. The basis of his lifelong investigation hinges on the single question, 'Why do animals build?' They have to fall back on their own bodily apparatus such as claws, beaks, teeth and jaws. But in the present context of a global pursuit by architects of ever more sustainable buildings, what rationale leads the animal world itself actually to build? Surely it is an intuitive combination of security needs, temperature protection, food retention in winter and even the disposal of accumulated waste: all of which exactly mirrors human requirements.