Housing and Social Environments of African (Loxodonta africana) and Asian (Elephas maximus) Elephants in North American Zoos

Abstract

We evaluated 255 African (Loxodonta africana) and Asian (Elephas maximus) elephants living in 68 North American zoos over one year to quantify housing and social variables. All parameters were quantified for the both the day and the night and comparisons were made across these time periods as well as by species and sex. To assess housing, we evaluated not only total exhibit size, but also individual animals’ experiences based on the time they spent in the unique environments into which the exhibits were subdivided. Variables developed to assess housing included measurements of area as a function of time (Total Space Experience), environment type (Indoor, Outdoor, In/Out Choice) and time spent on hard and soft flooring. Over the year, Total Space Experience values ranged from 1,273 square feet to 169,692 square feet, with Day values significantly greater than Night values (p<0.001). Elephants spent an average of 55.1% of their time outdoors, 28.9% indoors, and 16% in areas with a choice between being in or out. Time spent on hard flooring substrate ranged from 0% to 66.7%, with Night values significantly greater than Day (p<0.001). Social factors included number of animals functionally housed together (Social Experience) and social group characteristics such as time spent with juveniles and in mixed-sex groups. Overall Social Experience scores ranged from 1 to 11.2 and were significantly greater during the Day than at Night (p<0.001). There were few significant social or housing differences between African (N = 138) and Asian (N = 117) species or between males (N = 54) and females (N = 201). The most notable exception was Total Space Experience, with African and male elephants having larger Total Space Experience than Asian and female elephants, respectively (P-value<0.05). The housing and social variables evaluated herein have been used in a series of subsequent epidemiological analyses relating to various elephant welfare outcomes.

The Elephant Welfare Initiative: a model for advancing evidence‐based zoo animal welfare monitoring, assessment and enhancement

“…This 24 hour individual‐elephant approach to monitoring housing and social management generates metrics known as ‘Space Experience’ and ‘Social Experience’ as well as measures such as ‘Time with In/Out Choice’, ‘Time on Soft Substrates’ and ‘Time Housed Separately’, among others (for details on the calculation of these metrics see: Meehan, Hogan et al . , ).…”

“…‘Time on Soft Surfaces’, ‘Time with In/Out Choice’, ‘Time Housed Socially’) are evaluated based on goals developed from population‐level data (Meehan, Hogan et al . , ). Others use goals created by EWI members (e.g.…”

“…The housing‐experiences section evaluates the experiences of each elephant against several housing and social‐management goals derived from population‐level data (Meehan, Hogan et al . , ). Performance is noted by arc length, text and saturation changes to the herd and individual‐elephant indicators.…”

“…The physical and social environments of both African and Asian zoo elephants are important to their welfare (Meehan, Hogan et al ., ). For example, social variables are important predictors of daytime stereotypic behaviour, night‐time stereotypic behaviour and walking distances, and are a risk factor for hyperprolactinaemia, an endocrine system dysfunction (Brown et al ., ; Greco et al ., ; Holdgate, Meehan, Hogan, Miller, Soltis et al ., ).…”

“…For example, neither ‘Total Exhibit Size’ nor ‘Herd Size’ (both zoo‐level measures) has any known associations with elephant welfare outcomes and neither has been found to be a reliable proxy for ‘Space’ or ‘Social Experience’, which do predict variation in welfare outcomes (Meehan, Hogan et al . , ). Therefore, the tracking of an individual elephant's housing and social experiences during both the day and the night is an important aspect of meaningful welfare monitoring.…”