Estimating daily walking distance of captive African elephants using an accelerometer

Abstract

Two central concerns for elephant husbandry and management are whether zoological enclosures are appropriately sized and the degree to which naturalistic exercise and activity are observed in such enclosures. In order to address these issues, accurate data on the daily walking distance of elephants both in situ and ex situ are necessary. We used an accelerometer, a pedometer that measures step count and activity level, to estimate walking distance in African elephants (Loxodonta africana) at the San Diego Zoo's Wild Animal Park. The accelerometer was worn simultaneously with a GPS unit that recorded actual walking distance. Estimates of walking distance were extrapolated from the accelerometer and compared with actual distances determined by GPS data. The accelerometer was found to overestimate step count, and subsequently walking distance, by including false counts of steps. Extrapolating walking distance based upon stride length measurements did not match actual GPS walking distance. However, activity level output from the accelerometer significantly correlated with actual GPS walking distance. In addition, we report that the rate of movement is comparable to that reported in other zoological settings. We provide a linear regression equation that can be utilized by other institutions to estimate daily walking distance of elephants in their collection who are outfitted with accelerometers.

Accelerometers in collars identify behavioral states in captive African elephants Loxodonta africana

“…Even in terrestrial species, accelerometers can be used to record animal behavior automatically without human presence. Such devices have been employed to remotely measure animal walking distance (Rothwell et al 2011), animal orientation (Lyons et al 2005, Ringgenberg et al 2010, and animal activity level and metabolic rate (Wilson et al 2006, Halsey et al 2009, Enstipp et al 2011.…”

“…The goal of this study was to determine whether accelerometer data can effectively distinguish between several common elephant behaviors, expanding on work by Rothwell et al (2011) who placed accelerometers in anklets that measured elephant walking distance. Remote sensing devices such as GPS units have traditionally been attached to elephants by placing collars around their necks (e.g.…”

Using an active Radio Frequency Identification Real-Time Location System to remotely monitor animal movement in zoos

“…To our knowledge, this is the first use of powered, active RFID tags to monitor real-time individual animal movement and space use at a zoo. To monitor movement of elephants in environments such as zoos, attempts have been made to adapt technologies that include global positioning systems (GPS) in neck collars [5,6], and GPS and/or accelerometer units in bracelets [6,7]. Due to DZ's animal management restrictions and staff safety concerns, we were unable to use GPS neck collars for tracking elephant movement.…”

Accelerometers and simple algorithms identify activity budgets and body orientation in African elephants Loxodonta africana

“…Such acceleration data allows for the remote sensing of animal behavior without human presence. For example, accelerometers have been employed to detect activity levels (Wilson et al 2006, Halsey et al 2009, Enstipp et al 2011, body orientation (Lyons et al 2005, Ringgenberg et al 2010, movement through space (Rothwell et al 2011), speticular elephant, accelerometers could determine if interventions to increase activity, such as enrichment techniques, are effective (e.g. Soulsby 2012, Rothwell et al 2011.…”

“…For example, Rothwell et al (2011) showed that accelerometers in anklets can be used to count steps and infer walking distance in African elephants, and Ren & Hutchinson (2008) used accelerometers attached to the legs to investigate gaits of walking Asian and African elephants. In a multi-institutional study, Holdgate et al (2016) used accelerometers in anklets to measure recumbence in both Asian and African elephants.…”