The influence of ambient noise on maternal behavior in a Bornean sun bear (Helarctos malayanus euryspilus)

Abstract

Anthropogenic noise has become a pervasive feature of both marine and terrestrial habitats worldwide. While a comprehensive understanding of the biologically significant impacts of noise on wildlife is lacking, concerns regarding its influence persist. Noise is also a common feature in the zoological setting, and much can be learned regarding the species-typical response to ambient noise by studying animals in captivity. Here we correlate behavioral and vocal patterns in a Bornean sun bear (Helarctos malayanus euryspilus) mother and cub with ambient noise levels during the 6-month post-partum period. We hypothesized that loud ambient noise would be correlated with changes in behavior, and predicted that noise would be negatively correlated with maternal care behavior, potentially masking cub vocalizations or providing a distraction to the mother. Contrary to expectation, we found that the mother spent significantly more time attending to her cub (P=0.03) on loud days. We also found that she tended to spend less time feeding (P=0.08); however her time spent resting was not affected. The cub was approximately twice as vocal on loud days, although these results were not statistically significant (humming: P=0.10; squawks/cries: P=0.14). Taken together, these results suggest that the behavioral response to ambient noise may have potential energetic costs, and as a result efforts should be made to reduce ambient noise exposure during the post-partum period.

Dither: A unifying model of the effects of visitor numbers on zoo animal behavior

“…Examining the impacts of environmental stimuli on animals under human care has been an area of research interest over the last several decades. Increasingly, researchers are seeking to understand the impacts of lighting conditions (Buchanan-Smith & Badihi, 2012;Liu et al, 2017;Patel et al, 2016), ambient noise (Owen et al, 2014;Orban et al, 2017), and other possibly disruptive factors (Jakob-Hoff et al, 2019;Powell et al, 2006;Williams et al, 2021) on animal behavior or physiological stress measures. More recently, studies have expanded to other novel and potentially anxiety-inducing occurrences that combine several of these putatively disruptive factors (e.g., airshows: Cronin et al, 2018; late night visitor events: Bastian et al, 2020;Proctor & Smurl, 2020; walk-through exhibits: Woolway & Goodenough, 2017).…”

Potential Impact of Construction Noise on Selected Zoo Animals

“…Animals in zoos are routinely exposed to a variety of noises arising from visitors, ground maintenance, traffic and other sources. From time to time, zoo animals can also be exposed to potentially intense noise arising from construction activities [10,11,12,13]. Previous studies have demonstrated that this noise can elicit stress responses in some animals [12,13,14].…”

“…Owen et al [11], studied the impact of ambient noise on captive giant pandas over a four-year period and found that behavioral agitation occurred more often on noisy days and some stress indices were more pronounced in the female during estrus and lactation [11]. Another zoo study [10] comparing the behaviors of a female sun bear ( Helarctos malayanus ) and her cub on the loudest (Leq 68.5 dB) and quietest (Leq 62 dB) days during the six month post-partum period found that the dam spent more time on cub-directed behavior and less time feeding on the louder days.…”

Vocal activity of lesser galagos (Galagospp.) at zoos

“…Captive animals may also change their behavior, including decreasing vocal activity, as a consequence of environmental disturbances [Castellote and Fossa, ]. Noise emerging from the viewing public also has a significant effect on the behavior of zoo animals [Owen et al, ; Quadros et al, ; Larsen et al ]. Therefore, the first aim of our study was to investigate the natural vocal behavior of lesser galagos living at zoos, specifically to examine whether they spontaneously produce vocalizations that potentially can be used for species determination.…”