Although most beetles can fly, they generally do so only to move among low vegetation. They fly heavily and steer poorly. Often, as is the case with lady beetles, they have to climb to an elevated vantage point for a successful takeoff. Though some types of beetles (the tiger beetles or metallic wood-borers, for instance) are able to burst into flight rapidly when threatened, most others require lengthy preparations before becoming airborne.

Since beetles are cold-blooded, their body temperature is usually insufficient to to permit the wing muscles to move rapidly enough for flight. So the beetle must raise its body temperature by vibrating its wings. This pumps air into the body and expends metabolic energy. Right after takeoff, the heavier beetles hang almost vertically in the air and only become more horizontal as top speed is reached. Beetles fly with between 30 to 90 wingbeats per second. The elytra are held diagonally erect, and act as gliding surfaces and stabilizers; the work of flying is done by the elastic hind wings (alae).

Chewing mouthparts with well-developed mandibles allow beetles to eat a broad range of materials. They are known to eat leaves, bark, dung, and other insects as well as man-made fabrics. Some beetles are predators, some are herbivores or scavengers, and some are parasites. Beetle larvae, called grubs, can be predacious or herbivorous and sometimes cover themselves with protective shelters. All grubs have biting mouthparts. Most species produce only one generation a year, mating in spring and summer.