Orangutans Are Only Non-Human Primates Who Can 'Talk' About the Past

A new study published in the journal Science Advances revealed that when wild Sumatran orangutan mothers spotted a predator, they suppressed their alarm calls to others until the threat was no longer there.

This behaviour is called "displaced reference," or "the capacity to transmit information about something that is not present or about a past or future event," the authors wrote in the study. It's so rare that its only documentation in a non-human species is the dance of forager honeybees.