Grebes are small to medium-large in size, have lobed toes, and are excellent swimmers and divers. However, they have their feet placed far back on the body, can run for a short distance, but often fall over.
Grebes have narrow wings, and some species are reluctant to fly. They respond to danger by diving rather than flying, and are in any case much less wary than ducks.
Bills vary from short and thick to long and pointed, depending on the diet, which ranges from fish to freshwater insects and crustaceans. The feet are always large, with broad lobes on the toes and small webs connecting the front three toes.
Grebes can adjust their buoyancy. Often, they swim low in the water with just the head and neck exposed.
In the non-breeding season, grebes are plain-coloured in dark browns and whites. However, most have ornate and distinctive breeding plumages, often developing chestnut markings on the head area, and perform elaborate display rituals.
When preening, grebes eat their own feathers, and feed them to their young. The function of this behaviour is uncertain but it is believed to assist with pellet formation and to reduce their vulnerability to gastric parasites.
Grebes make floating nests of plant material concealed among reeds on the surface of the water.