Exploring the Link between Behavioural Needs and Stereotypic Behaviour in Ungulates

Abstract

Stereotypic behaviours are repetitive behaviours induced by frustration, repeated attempts to cope, or central nervous system dysfunction. They are widely reported across a variety of captive species, and are particularly common in ungulates. Stereotypic behaviours develop from the restriction of an animal’s behavioural needs - highly motivated actions critical to a species’ survival and reproduction - in captive environments. Cross-species analyses in other clades suggest that the different forms of stereotypic behaviour have heterogeneous causal mechanisms, and that drivers for stereotypy relate to both a species’ wild behavioural biology and their captive environment. The aim of this thesis was to explore the link between behavioural needs and stereotypic behaviour in ungulates, a relatively understudied clade. Study one found that ungulate behavioural needs relating to foraging and mating were associated with stereotypy, with browsing and promiscuous species showing the greatest prevalence of stereotypic behaviour. Concentrate-only diets and lack of ad libitum feed substrates in captivity were also associated with high rates of stereotypy. Exploratory analyses suggested that oral forms of stereotypy were associated with diet and feeding variables, and locomotor forms were associated with social factors. To explore this relationship between stereotypic behaviour and the behavioural need to perform social behaviours further I used the domestic horse (Equus caballus) as a model species. To gain an in-depth understanding of equine social behaviour within an experimental context, study two explored equine social communication through facial movements and head/neck position using EquiFACS. Horses demonstrated a wide repertoire of distinct facial expressions, and the specific movements associated with each behavioural context were identified. Study three utilised these results to interpret sociality in stereotypic and non-stereotypic horses, finding that box-walkers (a locomotor stereotypy) demonstrated greater levels of sociality than crib-biters (on oral stereotypy) and non-stereotypic horses. This suggests that it may be increased frustration of the behavioural need to perform social behaviours experienced by these individuals that acts as a driver for locomotor stereotypy development. Overall, results indicate that restrictions of behavioural needs relating to diet and feeding may lead to oral stereotypic behaviour in ungulates, whereas restrictions of social behaviour may underpin locomotor stereotypy.

Date of Award	26 Oct 2023
Original language	English
Awarding Institution	University of Portsmouth
Supervisor	Leanne Proops (Supervisor), Matthew Parker (Supervisor) & Sebastian D McBride (Supervisor)