First insights into the feeding habits of the Critically Endangered black snub-nosed monkey, Rhinopithecus strykeri (Colobinae, Primates)

Since its initial discovery in 2010 in the Gaoligong Mountains on the Sino–Myanmar border, there remains no direct information on the feeding habits of the black snub-nosed monkey (Rhinopithecus strykeri). This species is on the verge of extinction, with an estimated remaining population of < 400 individuals. Due to difficulties in following these monkeys across steep mountainous terrain, during 203 observation days (September 2015–January 2017) we recorded 80 h of behavioral records of a wild population (Luoma group). Our preliminary results identified 14 plant species and four lichen species consumed by the monkeys. In addition, we provided the only two captive individuals of this species with a cafeteria diet composed of > 600 wild-collected plant species that were gathered from known R. strykeri habitats to determine which plant species and food items were considered palatable. Our results indicate that the captive monkeys freely consumed young and mature leaves, fruits/seeds, buds, flowers, twigs, and bark from 170 different species of trees, bushes, and herbs representing 76 genera and 41 plant families, as well as 15 species of lichen. All foods consumed by the wild monkeys were also consumed by the captive individuals. Food plants consumed by R. strykeri were found principally in intact subtropical evergreen broadleaf forests and hemlock-broadleaf mixed forests at an altitude of 2200–3000 m. Strict enforcement of habitat protection and access to resources across this elevation zone appear to be essential for the conservation and survivorship of this critically endangered primate.