"Naturalness" and Its Relation to Animal Welfare from an Ethological Perspective

Here we view naturalness from the point of view of proximate behavioural control. The mechanisms of behaviour control have evolved in order that animals reach a specific goal after they have performed motivated behaviour. This goal was closely related to a function at the time when the mechanism evolved. Function and goal may be de-coupled in a novel environment such as artificial housing conditions. We argue that an animal that can perform the behaviour it wants and can reach the goals it likes can behave according to what is in-its-nature even under human influenced conditions. We illustrate this argument using abnormal sucking behaviour in calves and piglets as well as dehorning in cattle and goats. We conclude that a minimal welfare standard is ensured for animals that are given the opportunity to behave as is in-their-nature.