The study of animal behavior as observed in the natural environment and in the context of evolutionary adaptation.

The pioneering work of zoologist Konrad Lorenz (1903–1989) and biologist Nikolaas “Niko” Tinbergen (1907–1988) in the 1930s established a theoretical foundation for ethology, which had an effect on such wide-ranging disciplines as genetics, anthropology, and political science in addition to psychology.

Ethologists believe that an animal must be studied on its own terms rather than primarily in relation to human beings and with a focus on its normal behavior and environment. They study animal behavior from the dual perspective of both proximate explanations, which concern the individual lifetime of an animal, and ultimate explanations, which concern an animal's phylogeny (evolutionary history). Proximate explanations answer questions about how a specific behavior occurs whereas ultimate explanations answer questions about why a behavior occurs.

In a now-classic experiment, Lorenz managed to substitute himself for a mother graylag goose (Anser anser) by being the first creature the baby geese saw when they hatched from their eggs. He showed that young birds fixate, or imprinted, on the first living being they see, which in this case was Lorenz. The goslings perceived him as their mother and ignored their biological mother. This imprinting behavior proves a good strategy for goslings, which typically first see their mother and, therefore, follow her.

Lorenz described imprinting as a nonreversible behavioral response acquired early in life, normally released by a specific triggering stimulus or situation. Imprinting differs from ordinary learning in the following ways:

Goslings fixating on their mother is one example of imprinting. Another example occurs in north Pacific salmon in the genus Oncorhynchus. Newborn fish are believed to use their keen sense of smell to imprint on the stream in which they were born. They then migrate out to the ocean to live for several years and then use that imprinted odor to bring them back to their natal stream to breed.

Tinbergen also conducted a well-known experiment that helped shape the field of ethology. He studied ground-nesting common black-headed gulls (Chroicocephalus ridibundus) to learn why a mother gull removes all traces of eggshell from its nest after a chick hatches. He wanted to learn whether the removal of the eggshell perhaps prevented injuries, disease, or the attention of predatory birds. By placing pieces of shell in exposed locations away from the gulls’ nests, Tinbergen found that the white interior of the shells was visible from the air and did indeed attract predators. Therefore, he concluded that mother gulls who exhibit this behavior—removing the eggshells—provide better protection from predators and have better success in rearing their young.

The ethologist's method of studying an animal includes the creation of an ethogram, an objective description of its behavior patterns, such as hunting, eating, sleeping, fighting, and nest-building. The description of each activity includes the following:


Fixed action pattern—
An unlearned action activated by an innate releasing mechanism that occurs in response to a specific stimulus.
Innate releasing mechanism—
A stimulus that triggers or releases a behavior. This is part of a system or process that is present from birth: The animal exhibits a preprogrammed, stereotyped response to a stimulus.
Evolutionary history.
Proximate cause—
In terms of animal behavior, an event that occurs during the individual lifetime of an animal and results in a behavior. It explains how a behavior occurs.
Ultimate cause—
In terms of animal behavior, the background story about why a behavior occurs, which relates to an animal's phylogeny.

The researcher may then turn to existing data on related species in various habitats and/or conduct independent research with reference to the animal's natural environment. Experiments may be conducted within the environment itself, sometimes by investigating the effects of removing the animal from that environment or by adding another type of organism to the environment. Laboratory studies may also be done in relation to some aspect of the animal's own habitat.

Subsequently, the focus of ethological work shifted to include an increasing awareness that learning also plays an important role in explaining animal behavior. Young may learn from their parents or siblings or from their own experiences with other animals or situations. A simple form of learning is habituation. In this type of learning, an animal responds in a certain way the first few times it is confronted to a new stimulus, but if there is no need for that particular reaction, the animal may stop responding that way. Prairie dogs illustrate this point. If humans begin taking a trail near their burrow, the prairie dogs will give alarm calls the first few times they see humans on the trail. As they learn that humans are not dangerous to them, they will stop issuing the calls. In other words, they become habituated to humans.

Ethology remains an active field of study. One emerging subfield is molecular ethology. This subfield focuses on how genes can affect behaviors. Additional subdisciplines derived from classical ethology include sociobiology, which also involves gene study, and behavioral ecology, which relates behavior to the ecological conditions in which it occurs.

See also Behavior.



Alcock, John. Animal Behavior, 12th ed. Sunderland, MA: Sinauer Associates.

Alcock, John, and Paul W. Sherman. Exploring Animal Behavior: Readings from American Scientist, 6th ed. Sunderland, MA: Sinauer Associates.

Burkhardt, Richard W., Jr. Patterns of Behavior: Konrad Lorenz, Niko Tinbergen, and the Founding of Ethology. Chicago: University of Chicago Press: 2005.

Davies, Nicholas B., John R. Krebs, and Stuart A. West. An Introduction to Behavioural Ecology, 4th ed. Sussex, UK: Wiley Blackwell, 2012.

WEBSITES, “Konrad Lorenz—Biographical,” . (accessed July 17, 2015)., “Nikolaas Tinbergen—Biographical,” . (accessed July 17, 2015).


Animal Behavior Society, 2111 Chestnut Ave., Ste. 145, Glenview, IL, 60025, (312) 893-6585, info@animal, .