Simakobu or Pig-Tailed Snub-Nose Langur Simias concolor Miller, 1903 Indonesia (Mentawai Islands) (2002, 2004, 2006)

The simakobu monkey is serving as the flagship species for a group of endangered primates endemic to the remnants of forest on the 7,000-km˛ Mentawai Islands. The four main islands are located 85–135 km off of the west coast of Sumatra and are home to three other primate species—Kloss’s gibbon (Hylobates klossii), the Mentawai pig-tailed macaque (Macaca pagensis), and the Mentawai Island leaf langur (Presbytis potenziani). Simias concolor concolor Miller, 1903 inhabits the islands of Sipora, North Pagai, and South Pagai along with several small islets off southern South Pagai. Simias c. siberu Chasen and Kloss, 1927 occurs only on Siberut Island. Where Simias still occurs on the Pagai Islands, it exists at lower densities than on Siberut. Although the first simakobu specimens were collected in 1902, researchers did not begin studying the Mentawai primates until the 1970s. In 1996, two simakobu groups were habituated to the presence of humans and studied in Betumonga, in the southwestern region of North Pagai Island. Researchers with the Siberut Conservation Project in the Peleonan Forest in northern Siberut are in the process of habituating more simakobu and other primate groups. Simakobus are arboreal quadrupeds that eat leaves, fruits, and flowers, and exhibit a variable social organization. All four of the Mentawai primates are affected by habitat disturbance and hunting (Whittaker 2006). Although hunting appears to be declining and opportunistic, human encroachment and timber removal are increasing. Of the four Mentawai primates, simakobus seem to be the most sensitive to logging. On the Pagais, density estimates range from a high of 5.17 simakobus per km˛ in unlogged forests to a significantly lower density of 2.54 ind/km˛ in forests that were logged in the 1980s (Paciulli 2004). Twenty-five years ago, simakobus were found in areas of mixed primary and secondary forests on Siberut at densities as high as 220 ind/km˛ (Watanabe 1981). In 1990, however, no evidence could be found of Simias inhabiting several areas on Siberut and the Pagais (Tenaza and Fuentes 1995). Today, the Mentawai primates continue to exist in some residual forest patches on the Pagais and Sipora, and parts of the 190,500-ha (470,735 acres) Siberut National Park (also a UNESCO Biosphere Reserve) that covers 47% of the island. Thus, while Simias and the other Mentawai primates still survive in spite of human encroachment, hunting, and timber removal, the vast majority of the remaining natural habitat lies outside of officially protected areas. Most of these areas are in logging concessions and could very well be lost in the near future as there is talk of clear cutting in 2008 for oil palm plantations. Lisa M. Paciulli

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