Attacus atlas belongs to the Saturniidae, a family in which the adult mouthparts are reduced to non-functional remnants. The moth emerges from its cocoon with no means of drinking nectar or water. Its entire adult energy budget was assembled during larval feeding, when the caterpillar consumed leaves of citrus, cinnamon, guava and other broadleaf plants and accumulated fat.
The consequence is a compressed adult life, typically one to two weeks. Adults conserve energy, flying mainly at night and often resting through the day. Females emit pheromones and tend to move little, while males use large feathery antennae to detect those pheromones and locate them, sometimes over considerable distances.
Two claims about the atlas moth circulate widely and deserve correction. It is often called the largest moth in the world; by total wing surface area it is among the largest, but the white witch, Thysania agrippina, has a greater wingspan, and the Hercules moth rivals it in area. The snake-head resemblance of the wingtips is striking but its supposed deterrent effect has not been demonstrated experimentally.