Instituto nacional de Psiquiatría Ramón de la Fuente Muñiz, México D.F., Mexico.
Facultad de Psicología, Universidad Nacional Autónoma de México UNAM, Mexico D.F., Mexico.
Chronobiol Int. 2021 Jul;38(7):944-949. doi: 10.1080/07420528.2021.1903029. Epub 2021 Mar 28.
South American night monkeys (genus ) are the only nocturnal simian primates. Early activity recordings in North Colombian monkeys kept under semi-natural conditions and extensive chronobiological studies carried out in laboratory settings revealed a strictly nocturnal behavior and strong activity enhancing (disinhibiting) effects of moonlight or corresponding luminosities during the dark time. To check whether the results from captive individuals correspond to the behavior of wild monkeys, we carried out long-term activity recordings of a wild female in a tropical rainforest near San Juan de Carare, Northern Colombia. Our data from about 150 days of continuous activity records with an "Actiwatch Mini" (CamNtech, UK) accelerometer-data logger device, confirmed: (1) strictly nocturnal behavior, (2) a pronounced bimodal activity pattern with prominent peaks during dusk and dawn, and (3) a lunar periodic modulation (masking) of the night monkey's circadian activity rhythm due to distinct activity inhibiting effects of the absence of moonlight throughout the night. The results from this wild-living tropical night monkey are consistent with those from captive conspecifics studied decades earlier.
南美夜猴（属）是唯一的夜行灵长类动物。在北哥伦比亚的半自然条件下对猴子进行的早期活动记录和在实验室环境中进行的广泛生物钟研究表明，它们具有严格的夜行行为和月光或相应黑暗时间内的亮度的强烈活动增强（抑制）作用。为了检查圈养个体的结果是否与野生猴子的行为相对应，我们在北哥伦比亚圣胡安德卡雷雷附近的热带雨林中对一只野生雌性夜猴进行了长期的活动记录。我们使用“Actiwatch Mini”（CamNtech，英国）加速度计数据记录器设备进行了大约 150 天的连续活动记录，得到的数据证实：（1）严格的夜行行为；（2）明显的双峰活动模式，黄昏和黎明时活动明显增多；（3）由于整个夜间月光缺失导致明显的活动抑制作用，月相周期性调制（掩蔽）了夜猴的昼夜节律活动。这些来自野生热带夜猴的数据与几十年前研究的同类圈养动物的结果一致。
