The notion of ethological ‘need’, models of motivation and animal welfare
Publication Type: |
Journal Article |
Year of Publication: |
1988 |
Authors: |
B. O. Hughes, I. J. H. Duncan |
Publication/Journal: |
Animal Behaviour |
Keywords: |
animal welfare |
ISBN: |
0003-3472 |
Abstract:
The increasingly widespread use of the term ethological ‘need’, implying that the welfare of animals in intensive husbandry systems will suffer if they are unable to express a normal range of behaviour patterns, has been criticized on the grounds that the term has not been clearly defined nor does it rest on a solid scientific foundation. In this critical review, evidence is presented which is consistent with the idea that there are cases in which the performance of behaviour itself does have motivationally significant consequences which are not necessarily related to functional requirements. For example, hens go through nest-building sequences during pre-laying behaviour, even though the nest they created previously is still available. This kind of finding is difficult to explain without involving the concept of ethological ‘need’. Existing models of motivation are shown to be inadequate in explaining much of the behaviour seen in barren or impoverished environments, or when the animals are highly motivated in situations where consummatory behaviour is difficult to carry out. A modified model which can account for the occurrence of these stereotyped, abnormal and repetitive behaviour patterns is presented. The problems raised by equating the term ‘need’ with ‘necessity’ are discussed, particularly in the context of intensive environments where animals are faced with the task of occupying long periods of time with a limited range of behaviour patterns; the authors agree with Dawkins that one solution is its replacement by the concept of ‘elasticity’, but argue that the notion of ‘necessity’ may need to be broadened.