The Ancestor's Tale: A Pilgrimage to the Dawn of Evolution

by Richard Dawkins

though not necessarily for the human inhabitants, one of the main places where it flourishes is the town of Darwin in northern Australia. Termites bestride the tropics like a distributed colossus. In tropical savannahs and forests, they reach population densities of 10,000 per square metre, and are estimated to consume up to a third of the total annual production of dead wood, leaves and grass. Their biomass per unit area is double that of migrating herds of wildebeest on the Serengeti and Masai Mara, but is spread across the entire tropics. If you ask the source of the termites’ alarming success, it is twofold. First, they can eat wood, which includes cellulose, lignin and other matter that animal guts normally can’t digest. I’ll return to this. Second, they are highly social and gain great economies from division of labour among specialists. A termite mound has many of the attributes of a single large and voracious organism, with its own anatomy, its own physiology and its own mud-fashioned organs, including an ingenious ventilation and cooling system. The mound itself stays in one place, but it has a myriad mouths and six myriad legs, and these range over a foraging area the size of a football pitch. Termites’ legendary feats of co-operation are possible, in a Darwinian world, only because the majority of individuals are sterile but closely related to a minority who are very fertile indeed. Sterile workers act like parents towards their younger siblings, thereby freeing...