Oskar Heinroth (1 March 1871 – 31 May 1945) was a
German biologist who was one of the first to apply the methods of comparative
morphology to animal behaviour, and was thus one of the founders of
ethology. His extensive studies of behaviour in the
Anatidae (ducks and geese) showed that
instinctive behaviour patterns correlated with
taxonomic relationships determined on the basis of morphological features. He also rediscovered the phenomenon of
imprinting, reported in the 19th century by
Douglas Spalding but not followed up at the time. His results were popularised by
Konrad Lorenz, whose mentor he was. Lorenz regarded Heinroth as the true founder of the study of animal behaviour seen as a branch of zoology.