Precocial

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In biology, precocial species are those that are relatively mature and mobile from the moment of birth or hatching. The opposite of precocial is altricial. Precocial species are normally nidifugous, meaning that they leave the nest shortly after birth.

The distinction between precocial and altricial species is particularly sharp in birds. Precocial birds, including many ground-nesting species, have offspring that are born covered with down and ready to leave the nest in a short period of time following hatching (e.g. 24 hours). This amount of time is necessitated by the fact that offspring require time for their downy coats to dry prior to leaving the nest. Additionally, most precocial chicks lack thermoregulation (the ability to regulate their own body temperatures), and they depend on the attending parent(s) to provide an outside source of heat for a short period of time. Precocial birds find their own food. Examples of precocial birds include the domestic chicken, many species of ducks and geese, and rails and crakes.

Precociality is also found in many other animal groups. Familiar examples of precocial mammals are most ungulates, the guinea pig, and most species of hare. This last example demonstrates that precociality is not a particularly conservative characteristic, in the evolutionary sense, since the closely related rabbit is highly altricial.

Precocial species typically have a longer gestation or incubation period than related altricial species, and smaller litters or clutches, since each offspring has to be brought to a relatively advanced (and large) state before birth or hatching.

The phenomenon of imprinting studied by Konrad Lorenz is characteristic of precocial birds.