Vocal activity of lesser galagos (Galagospp.) at zoos

Abstract

Almost nothing is known about the natural vocal behavior of lesser galagos living in zoos. This is perhaps because they are usually kept in nocturnal exhibits separated from the visitors by a transparent and acoustically insulating glass barrier. The aim of the present study was therefore to fill this gap in knowledge of the vocal behavior of lesser galagos from zoos. This knowledge might be beneficial because the vocalizations of these small primates can be used for species determination. We performed a 10-day-long acoustic monitoring of vocal activity in each of seven various groups of Galago senegalensis and G. moholi living at four zoos. We quantitatively evaluated the occurrence of four loud vocalization types present in both species, including the most species-specific advertisement call. We found that qualitative as well as quantitative differences exist in the vocal behavior of the studied groups. We confirmed that the observed vocalization types can be collected from lesser galagos living at zoos, and the success can be increased by selecting larger and more diverse groups. We found two distinct patterns of diel vocal activity in the most vocally active groups. G. senegalensis groups were most vocally active at the beginning and at the end of their activity period, whereas one G. moholi group showed an opposite pattern. The latter is surprising, as it is generally accepted that lesser galagos emit advertisement calls especially at dawn and dusk, i.e., at the beginning and at the end of their diel activity.

Comparative Ecology and Behaviour of Eastern Potto Perodicticus ibeanus and Central Potto P. Edwardsi in Angola, Cameroon, Kenya, Nigeria, Rwanda and Uganda

“…Slender lorises emit a variety of whistles, while slow lorises make series of 'Kriks', 'Pants', and high-pitched 'Whistles' (Nekaris & Bearder, 2011). Vocalisations can be useful for discerning among species, as has been done with morphologically cryptic species of galagines (Courtenay & Bearder, 1989;Anderson et al, 2000;Ambrose, 2003;Schneiderová et al, 2016;Svensson et al, 2017). Future studies should be alert for vocalisations in pottos and of their potential use in taxonomy.…”

Activity Budget and Sociality of the Northern Lesser Galago, Galago senegalensis

“…The galago crawled for 20 s and then froze still with one arm close to the body and the other stretched out on the branch for 2 min 34 s. The civet then moved off and out of sight, and the galago then leapt in the other direction, back to where the other two individuals were seen. After 1 min and 44 s, the galago began producing frequent "attention or alarm" calls ("tjong" : Zimmermann, 1989;Anderson et al, 2000;Schneiderová et al, 2016) every few seconds. Around 2 min after the vocalisations started, the galago defecated a loose stool.…”

“…The behaviour observed was in response to an encounter with a potential predator (an African civet). The individual seemed extremely distressed, producing frequent "attention/alarm" calls ("tjong": Zimmermann, 1989;Anderson et al, 2000;Schneiderová et al, 2016), and an uninvolved galago appeared and groomed the victim until the vocalisations stopped. Consolation is a very complex behaviour once thought to be unique to apes (Preston & de Waal, 2002).…”

From Soundwave to Soundscape: A Guide to Acoustic Research in Captive Animal Environments

“…This allowed continuous monitoring from a hydrophone array on the floor of the enclosure and saved researchers over 6 days of manual labor per month processing acoustic data ( 68 ). Other reports of acoustic monitoring in captive wildlife have been short-term e.g., for several days or weeks but often over limited hours [e.g., galagos, Galago spp., ( 79 )], rather than having permanent systems in place. Time-restricted acoustic monitoring could underestimate vocal activity, and miss rare and/or sporadic sounds with high biological significance.…”