<p><strong>Southern pig-tailed macaques in <a href="http://travel.nationalgeographic.com/travel/countries/indonesia-guide/">Indonesia</a>'s Bukit Barisan National Park are caught in the sights of 1 of 420 camera traps set up in seven tropical countries for a 2008-2010 study. </strong></p><p><strong>Generating some 52,000 pictures, this first ever global <a href="http://animals.nationalgeographic.com/animals/mammals/">mammal</a> study to use the traps uncovered pervasive trends in mammal decline, which underscore the importance of large protected areas, according to organizers. </strong></p><p>Seen as facing a high risk of extinction in the wild by the <a href="http://www.iucnredlist.org/apps/redlist/details/12555/0">International Union for Conservation of Nature (IUCN)</a>, the pig-tailed macaques are said to have suffered "very serious" habitat loss, mainly due to agriculture and logging, in parts of their range in Southeast Asia, according to the group.</p><p>The monkey's plight is no surprise. "The results of the study are important in that they confirm what we suspected," study leader <a href="http://www.teamnetwork.org/en/about/people/JAhumada">Jorge Ahumada</a>, an ecologist with <a href="http://www.conservation.org/Pages/default.aspx">Conservation International</a>, said in a statement.</p><p>"Habitat destruction is slowly but surely killing our planet's mammal diversity."</p><p>(Also see <a href="http://news.nationalgeographic.com/news/2011/08/pictures/110801-big-cats-rare-antelope-elephant-camera-trap-kenya-forest-animals/">"Pictures: Rare Antelope, Big Cats Caught by Camera Trap."</a>)</p>