Ecology and Conservation of the Hose’s Langur Group (Colobinae: Presbytis hosei, P. canicrus, P. sabana): A Review

Abstract

The grey-backed langurs Presbytis hosei sensu lato are little-known colobines from northern Borneo. Comprising one, two or possibly three distinct species, the attention these taxa have received from conservationists or from the primatological community is limited. Some people may be familiar with the species from Leo Berenstain’s “The Wind Monkey and other stories” published in 1994, in which P. (h.) canicrus is the wind monkey referred to in the title. This same taxon gained some fame when it was included as Miller’s Grizzled Surili on the 2004-2006 “Top 25 Most Endangered Primates” (Brandon-Jones 2005). While Brandon-Jones (2005) indicated that the species was known only from the north-east Indonesian part of Borneo, the sorry state of the forest in Kutai National Park, the only protected area of its recorded range, led him to suggest that P. (h.) canicrus was probably Critically Endangered or even Extinct. Reflecting the lack of attention to the species, he did indicate that no surveys had been undertaken. Apart from Indonesia - P. (h). hosei, P. (h.) canicrus and possibly P. (h.) sabana- grey-backed langurs occur in the Malaysian State of Sarawak and the Brunei Sultanate - P. (h.) hosei- and in the Malaysian State of Sabah - P. (h). hosei and P. (h.) sabana.

Here I aim (1) to provide a comprehensive overview of the ecology and habitat use of the different taxa comprising the Hose’s langur group; (2) to give an overview of the densities at which the different taxa occur in pristine forest areas and in selectively logged forest; and (3) to review the threats Hose’s langurs face, with a strong focus on hunting. Throughout this review, there is a strong emphasis on the situation in Indonesia, noting that some aspects of the species biology are better studied in the Malaysian part of their range.