National Geographic : 2011 Aug
• Long tails help langurs stay balanced on cliffs. They're also good for yanking; the observer above is missing a golden opportunity. Juveniles like those playing at right have a truly rough-and-tumble life. More than half of these monkeys are killed by disease, predators, or infanticide---common practice when a new male takes over a langur group---but survivors can live nearly 40 years.