Scientific approaches to enrichment and stereotypies in zoo animals: what's been done and where should we go next?

Abstract

The zoo scientific community was among the first to focus attention on captivityinduced stereotypic behaviors, their causes, and methods of eradication. Environmental enrichment has emerged recently as the main husbandry tool for tackling this problem. An increasing number of research publications have attempted to evaluate the effectiveness of enrichment in reducing stereotypic behavior and to develop further concepts to explain how effective enrichment works. A review and meta-analysis of this literature indicates that enrichment is a successful technique for reducing stereotypic behavior in zoo animals. Enrichment was associated with significant reduction in stereotypy performance about 53% of the time. Published enrichment and stereotypy research is lacking for most zoo species, with most studies on large, charismatic, and often endangered species, but it is unclear whether stereotypies are more prevalent in these species. In addition, problems with scientific methods and data presentation, quantitatively detailed in this work, severely limit the conclusions drawn from zoo research. Further understanding of what kinds of enrichment works and what doesn't will require greater attention to experimental design, sample size, statistical analysis, and better descriptions of enrichment properties and the form of stereotypy. We recommend that future studies focus on increasing sample size (e.g., through multi-institutional studies), appropriate repeated measures design (e.g., with multiple baseline and experimental phases), providing full statistical information about the behavioral changes observed (including standard error), and ultimately the development of a predictive science for enrichment, stereotypies, and wellbeing.

Frustration and perseveration in stereotypic captive animals: Is a taste of enrichment worse than none at all?

“…As one would expect, animals raised in unenriched conditions but then provided with enrichment tend to show reductions in stereotypic behaviour-as demonstrated experimentally, for instance in research rodents [4,51], as well as via meta-analyses of environmental enrichments' effects on zoo animals [47,49,50]. The beneficial effects of added enrichments vary in magnitude: different enrichments vary in efficacy [47,49,50] and individuals vary in their responses, e.g. elderly animals' stereotypic behaviours are often resistant to enrichment [4,14,54].…”

Efficacy of foraging enrichments to increase foraging time in Grey parrots (Psittacus erithacus erithacus)

“…Environmental enrichment may help reduce behavioural problems and provide the animal with opportunities to perform its normal behaviour and cope with its captive living environment (Newberry, 1995;Young, 2003;Swaisgood and Shepherdson, 2005). Foraging enrichment in particular appears to be among the most effective measures (Crocket, 1998;Miller and Mench, 2005;Dixon et al, 2010) as the provision of foraging opportunities in captivity was found to 1) increase activity; 2) provide cognitive stimulation and manipulative activities; 3) alleviate stress, frustration and boredom; and 4) reduce and prevent aggression, and abnormal repetitive behaviours, including stereotypies (Bloomsmith et al, 1988;Shepherdson et al, 1993;Spoolder et al, 1995;Baker, 1997;Aerni et al, 2000;Bashaw et al, 2003;Johnson et al, 2004;Honess and Marin, 2006;VargasAshby and Pankhurst, 2007;Brinch-Riber and Mench, 2008).…”

Activity and enrichment use in disabled Asiatic black bears (Ursus thibetanus) rescued from bile farms

“…One possible reason for poor recovery could be little use of the provided environmental enrichments. Environmental enrichment, widely used by animal keepers to improve welfare (eg in zoos), can be defined as the identification and provision of "environmental stimuli necessary for optimal psychological and physiological wellbeing" (Swaisgood & Shepherdson 2005;see Young 2003, for examples of treatments considered to be enriching). In various species, enrichments have been shown, for example, to decrease anxiety and stress-related corticosterone reactivity (eg Benaroya-Milshtein et al 2004) and to reduce time spent performing stereotypic behaviour (reviewed in Shyne 2006;Swaisgood & Shepherdson 2006).…”