The <a href="//commons.wikimedia.org/wiki/Siamang" class="mw-redirect" title="Siamang">siamang</a> is a <a href="//commons.wikimedia.org/wiki/Gibbon" class="mw-redirect" title="Gibbon">gibbon</a> and like the latter, it is an ape, not a monkey. The chief characteristics distinguishing apes from monkeys are the absence of a tail, their more or less upright posture and the high development of their brain. (<a href="//commons.wikimedia.org/wiki/Chimpanzee" class="mw-redirect" title="Chimpanzee">Chimpanzees</a>, <a href="//commons.wikimedia.org/wiki/Bonobo" class="mw-redirect" title="Bonobo">bonobos</a>, <a href="//commons.wikimedia.org/wiki/Gorilla" title="Gorilla">gorillas</a>, <a href="//commons.wikimedia.org/wiki/Orangutan" class="mw-redirect" title="Orangutan">orangutans</a> and <a href="//commons.wikimedia.org/wiki/Human" class="mw-redirect" title="Human">humans</a> are also <a href="//commons.wikimedia.org/wiki/Ape" title="Ape">apes</a>.)  The Siamang is always black in color, with reddish-brown eyebrows. It differs from other gibbons in that it has a webbing between the second and third toe. The largest of the gibbon family, Siamangs are also the best at walking on two legs. Like other gibbons, they have tough, horny pads on their buttocks known as ischial callosities. Since Siamangs and Gibbons build no sleeping nest, the pads help them spend a comfortable night seated on tree branches safe from predators.
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/28567825@N03">Cliff</a> from Arlington, Virginia, USA
CC BY 2.0
<p><a rel="nofollow" class="external text" href="https://www.flickr.com/photos/nostri-imago/2854164099/">Siamang (Pongidae Hylobates syndactylus)</a>
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<ul><li>Uploaded by <a href="//commons.wikimedia.org/wiki/User:Magnus_Manske" title="User:Magnus Manske">Magnus Manske</a></li></ul>