Why do animals eat? Niko Tinbergen insisted there are four right answers
Ask why an animal eats and you could answer hunger, nutrition, childhood development or ancestry. Niko Tinbergen argued all four are needed at once. His framework, and the Nobel Prize he shared with Konrad Lorenz and Karl von Frisch in 1973, turned watching animals into a rigorous science called ethology.
Ethology is the zoology of behaviour in animals other than humans, blending lab work and fieldwork with neuroanatomy, ecology and evolution. Its name joins the Greek for character with the suffix for study, and the American entomologist William Morton Wheeler popularised it in 1902. Roots reach back to Darwin, whose 1872 book on emotional expression in humans and animals inspired many followers, and to ornithologists such as Charles Whitman, Oskar Heinroth and Wallace Craig. Darwin's protégé George Romanes tried to study animal minds through anecdote and human-style interpretation, an approach that never won scientific acceptance.
Instead, early workers including Eugène Marais and Julian Huxley focused on instinctive actions shown by every member of a species in a given situation. Their first step with any new animal was an ethogram, a catalogue of its main behaviours and how often each occurs, building an objective record. The modern field is usually dated to the 1930s, when Lorenz, Tinbergen and von Frisch put it on a firm footing in continental Europe. After the war Tinbergen moved to Oxford, and Cambridge researchers William Thorpe, Robert Hinde and Patrick Bateson strengthened British work.
Tinbergen's four questions ask about function, meaning how a behaviour helps survival and breeding; causation, the triggers and recent learning behind it; development, how it changes with age and experience; and evolutionary history, how it compares across related species. They complement each other. Hunger is the immediate cause of eating, yet hunger exists precisely because it drives animals to get nutrients, so saying we eat from hunger rather than for nourishment confuses two levels of explanation.
The emphasis later shifted toward groups. In 1972 John Crook argued the field had been mostly comparative, studying individuals, and needed to tackle social structure; the same year a society for human ethology was founded. E. O. Wilson's Sociobiology of 1975, and ideas from Robert Trivers and W. D. Hamilton, pushed social behaviour to the centre, and behavioural ecology reshaped the discipline. In 2020 philosophers Tobias Starzak and Albert Newen proposed that animals may hold beliefs.
Source: Ethology
