Dusky leaf monkey, spectacled langur, or spectacled leaf monkey (<i>Trachypithecus obscurus</i>) - <a rel="nofollow" class="external text" href="http://www.thainationalparks.com/kaeng-krachan-national-park">Kaeng Krachan National Park</a>.
The sound at background far away is from a singing Lar Gibbon (<i>Hylobates lar</i>).
<a href="//commons.wikimedia.org/wiki/User:Rushenb" title="User:Rushenb">Rushenb</a>
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<span class="int-own-work" lang="en">Own work</span>