According to a new study from Chinese neuroscientists Fan Xu and colleagues, some monkeys can experience depression in a similar way to humans. The researchers studied cynomolgus monkeys, also known as crab-eating macaques (Macaca fascicularis), a species native to Southeast Asia. Cynomolgus monkeys are highly social animals. Xu et al. previously showed that isolating a monkey from its companions caused it to develop depression-like behaviors. In their new paper, the authors say that they've noticed that some monkeys seem to become depressed naturally, without any human intervention. They observed the monkeys in a large primate breeding facility in Suzhou, China:
From April to November 2010, by means of a scanning method on a total population of 1007 adult female cynomolgus monkeys across all 52 enclosures, we identified subjects displaying depressive behavior using the following operational definition: slumped or collapsed body posture, diminished interest in feeding and sex, and diminished communication ...
