Wanderlust World Wanderlust World The yellow monkey is more formally known as the yellow-tailed woolly monkey, or Oreonax flavicauda. This primate was not identified until the 19th century (and then only from a pelt), and not seen again until late in the 20th century. It lives only in the remote mountain forests of small sections of Peru, thousands of feet above sea level, in small groups of not more than 10 monkeys. Perhaps a few hundred yellow monkeys still live in the wild.
Like other New World monkeys, the yellow monkey boasts a prehensile tail, a most useful adaptation when feeding in or moving through the tree canopy. Old World tailed primates have lost or never evolved this branch-grabbing and locomotion feature; some primates, most notably humans and gorillas, have lost their tails altogether. Ridges on the end of the monkey's tail, which is as long as its body, strengthen its grip. The yellow monkey also sports a thick coat, essential for survival in the Andean cold. They're flat-nosed, with side-facing nostrils; Old World monkeys have more prominent noses and front-facing nostrils. They have fewer teeth than Old World monkeys -- scientists aren't sure exactly why. They also have longer limbs in proportion to their body size, which tends to be smaller than their African and Asian relatives -- both advantages for treetop living. A monkey 3-feet from tip to tail and weighing less than 20 lbs. can leap 49 feet.
All New World monkeys, like the yellow monkey, are native only to South America. Scientists doubt that they got there via the Siberia-to-Alaska land bridge, or arose spontaneously, so the yellow monkey's ancestors floated across the Atlantic or diverged from a common primate ancestor when the continents broke up, take your pick. As befits a treetop dweller, the yellow monkey has adapted to a frugivorous diet -- that is, largely fruit, with the occasional flower, leaf or slow-moving insect tossed in.
The yellow monkey's most successful adaptation -- living quietly high up in trees, almost invisibly, for years, so that no one knew it was there -- no longer applies. As of the early 21st century, roads make even the most inaccessible forests accessible and while ecotourists are not a threat, poachers are. Officially, the critically endangered species is officially protected, but logging, mining and subsistence hunting continue to take a toll on the monkey and its habitat.