Why do termites build giant mounds with vents and tunnels?

Many termites live in large, engineered nests that can function like climate-controlled buildings. Mounds and internal tunnels help move air, remove carbon dioxide and keep the nest within a stable range of temperature and humidity. In some species, mound structure supports fungal gardens, eggs and thousands or even millions of workers and soldiers. Studies of termite mounds have inspired architectural research because the ventilation works without mechanical fans. The best-known African termite mounds can be several meters tall and are built by tiny insects using soil, saliva and dung.