Programa de Pós-graduação em Ciências Biológicas (Zoologia), Universidade Federal da Paraíba, João Pessoa, 58051-900, Brazil.
Laboratório de Ecologia, Comportamento e Conservacão (LECC), Departamento de Zoologia, Universidade Federal de Pernambuco, Recife, Brazil.
Primates. 2021 Jan;62(1):199-206. doi: 10.1007/s10329-020-00859-6. Epub 2020 Aug 29.
Terrestriality in Platyrrhine primates is primarily associated with low arboreal resource availability, low predation risk when on the ground and increased contact time with human observers. To test the relationship between these variables and ground use frequency, we studied a group of endangered Coimbra-Filho's titi monkeys (Callicebus coimbrai) in a 14-ha forest fragment in north-eastern Brazil. Terrestriality data were collected on a monthly basis (33 months) using scan sampling procedures from July 2008 to July 2012. Overall, Coimbra-Filho's titi monkeys were recorded during 0.6% of observation time (113 out of 18,164 scans) on the ground. Most of the time on the ground was spent feeding on young leaves (71 records) and the least amount of time on fruits (14 records). Availability of arboreal foods, rainfall, and time of contact with human observers did not influence overall terrestrial behaviour (ground use). However, the timing and nature of the monkeys' terrestrial feeding was strongly related to the absence of arboreal fruit (β-estimate = -3.078) and young leaf (β-estimate = -3.515) food resources. We suggest that terrestrial feeding by Coimbra-Filho's titi monkeys could be an adaptation to low arboreal fruit availability and the exploitation of alternative food resources.
地栖性在阔鼻猴类中主要与低的树栖资源可用性、地面时较低的被捕食风险以及与人类观察者的接触时间增加有关。为了检验这些变量与地面使用频率之间的关系，我们对巴西东北部一个 14 公顷的森林片段中的一组濒危的库氏毛丝鼠（Callicebus coimbrai）进行了研究。使用扫描采样程序从 2008 年 7 月到 2012 年 7 月，每月收集一次地栖性数据（33 个月）。总体而言，库氏毛丝鼠在观察时间的 0.6%（18164 次扫描中的 113 次）被记录在地面上。在地面上的大部分时间都花在吃嫩叶上（71 次记录），而在果实上的时间最少（14 次记录）。树栖食物的可用性、降雨量以及与人类观察者接触的时间都没有影响总体的地面行为（地面使用）。然而，猴子的地面觅食的时间和性质与缺乏树栖果实（β估计值=-3.078）和嫩叶（β估计值=-3.515）食物资源密切相关。我们认为，库氏毛丝鼠的地面觅食可能是对低的树栖果实可用性和对替代食物资源的利用的一种适应。
