Heini Hediger (30 November 1908 – 29 August 1992) was a Swiss biologist noted for work in proxemics in animal behavior and is known as the "father of zoo biology". Hediger was formerly the director of Tierpark Dählhölzli (1938–1943), Zoo Basel (1944–1953) and Zürich Zoo (1954–1973).
Hediger described a number of standard interaction distances used in one form or another between animals. Two of these are flight distance and critical distance, used when animals of different species meet, whereas others are personal distance and social distance, observed during interactions between members of the same species. Hediger's biological social distance theories were used as a basis for Edward T. Hall's 1966 anthropological social distance theories.
In the 1950s, psychologist Humphry Osmond developed the concept of socio-architecture hospital design, such as was used in the design of the Weyburn mental hospital in 1951, based partly on Hediger’s species-habitat work.
In 1942 Heini Hediger developed the science of wild animals kept in human care and published his concept of a new, special branch of biology, called “zoo biology”. The main statement is that animals in zoos are not to be considered as “captives” but as “owners of property”, namely the territory of their enclosures.They mark and defend this territory as they do in the natural environment and if the enclosures contain these elements which are of importance to them also in their natural environment, they have neither need nor desire to leave this property, but to the contrary, stay within it, even when they would have the opportunity to escape, or return to this “safe haven”, should they by accident have escaped. He consequently emphasized that the quality of the enclosures (“furnishing”, structure) is equally, or even more important than quantity (space, dimensions) and substantiated this with observations in the natural habitat. Among many other things he made clear that animals in the natural habitat do not need huge spaces, when all their needs can be satisfied within close range, that, in fact, animals do not move about for pleasure but to satisfy their needs. Zoo biology therefore implies that the life of animals in their natural surroundings must be studied in order to provide them with appropriate keeping conditions in human care. In animal husbandry, the aim of this concept — guided by the maxim “changing cages into territories” — was to meet the biological and ethological requirements of the exhibited animals. Hediger's publications influenced the keeping of wild animals in human care in particular also in the construction of enclosures and the planning of zoos.