Acting sustainably, like the hoop snake, is an enduring idea. In ancient myths a snake biting its tail symbolises continuity and renewal – perfectly self-sufficient. In Norse myths when the World Serpent lets go of its tail the world ends. Indigenous Australians tell how the rainbow serpent created the world. Today’s thinkers adopt the hoop snake as a symbol representing an eternal circle of change and re-creation. The hoop snake, which travels from the old worlds to the new as a legendary beast attacking the unwary traveller, stays with us. Acting sustainably describes a virtuous cycle of social change and renewal. The environments upon which we rely include our communities, enabling the economies that both consume and conserve them. Understanding our social context is the key to acting sustainably.