Into the night: camera traps reveal nocturnal activity in a presumptive diurnal primate, Rhinopithecus brelichi

• DOI: 10.1007/s10329-012-0318-2
• Publication Date: 2012-07-28T12:20:55Z
• Authors: Chia L. Tan; Yeqin Yang; Kefeng Niu
• Keywords: Diel vertical migration; Animal ecology; Camera trap; Dusk; Twilight

Most living primates exhibit a daytime or nighttime activity pattern. Strict diurnality is thought to be the rule among anthropoids except for owl monkeys. Here we report diel pattern of an Asian colobine, Guizhou snub-nosed monkey Rhinopithecus brelichi, based on methodology that relied using 24-h continuously operating camera traps. We conducted study in Fanjingshan National Nature Reserve Guizhou, China from March 22 May 19 and June 17 October 14, 2011. After standardizing all time elements meridian-based according geographic coordinates site, showed unequivocally monkeys, though predominantly diurnal, exhibited beyond daylight hours throughout study. Specifically, their at night during twilight periods suggests complex interplay behavioral adaptations, others, temperate environment where day length food resources fluctuate substantially across seasons. contend that, under prevailing ecological conditions, so-called strictly diurnal may adjust schedule opportunistically order increase energy intake. also discuss advantages traps primate studies, how standardized use by researchers would benefit comparisons patterns primates.