This installment deals with how animals construct their shelters from the elements and predators. Burrows and holes can provide considerable refuge, and Attenborough inspects the home of the American prairie dog, an elaborate construction that has its own air conditioning system. Silk is such a valuable commodity that those that can't make it steal it instead. The hermit hummingbird uses it to attach its nest to the underside of a leaf, while the Indian tailorbird stitches two leaves together. However, the expert in complex nest-building is the weaverbird which makes its abode from over 1,000 strips of grass that are perfectly interwoven - and dismantling it if it fails to attract a mate. The beaver is responsible for one of the biggest animal dwellings: its wooden lodge that rises from the river bed stays in place from one generation to the next, and so requires constant maintenance. Some stingless bees use their wax and the resin of tree bark to create labyrinthine structures containing various compartments. Mud is also used by several creatures, such as the potter wasp and the cliff swallow. The termites' intricate creations allow for security, heating, air conditioning, self-contained nurseries and gardens, and sanitation systems. Attenborough hails the species as the consummate home maker, and explores a 15-foot colony in West Africa that contains 1.5 million insects: he crawls right inside to examine its method of ventilation.