You know the feeling that people are talking about you when they start whispering as soon as you enter the room? Well, don't walk into this cage of cotton-top tamarins at the Central Park Zoo in New York City!
Researchers Rachel Morrison and Diana Reiss of The City University in New York were doing a research project on the monkeys by recording their loud calls and "mobbing behavior" in response to seeing people they fear. But, when a supervisor whom the monkey disliked entered their enclosure, the researchers noticed that the monkeys went quiet.
It turns out that the tamarins weren't exactly silent. When Morrison and Reiss examined their recordings, they realized that the monkeys were still chirping, but in a volume too soft for humans to hear. In effect, the tamarins were whispering to each other, potentially about what to do about the intruder.
"Psst, could you believe what that guy's wearing?" Image: Postdlf/Wikipedia
In the study, published in the scientific journal Zoo Biology, Morrison and Reiss noted that the "low amplitude vocalizations" were previously unknown in the species and that if it were not for their serendipitous recording and subsequent analysis of the spectrogram, the monkey whispers would likely have remained a secret of the tamarins.
"Although it is unclear what the motivational state of the tamarins was when in presence of the supervisor, it appears that they were responding to him as an ambiguous threat and may have been investigating the situation by cautiously approaching him to determine the actual level of threat and communicating to each other the appropriate behavioral response to take," the researchers said, as quoted by PopSci.
The researchers speculated that other species may utilize similar methods of communications to avoid being overheard by predators.
So the next time you go to the zoo and the monkeys turn quiet, they're probably talking about you!