A new study shows wild chimpanzees consider their peers level of attention when deciding if they need to alert them of danger, the BBC reported. Researchers found wild chimps that saw a poisonous snake were more likely to make an "alert call" if they were near a chimp that had not seen the snake.

It shows the animals "understand the mindset" of others, according to the report. The research will be in the journal Current Biology, and the University of St Andrews scientists who performed the work study primate communication to understand the development of human language. In order to figure out how chimps communicated about potential danger, researchers used plastic snakes to try to frighten the chimps. They camouflaged the snakes along the well traveled paths of the wild chimps and waited for their reactions.

"These [snake species] are well camouflaged and they have a deadly bite," Dr Catherine Crockford from University of St Andrews, who led the research told BBC Nature.

"They also tend to sit in one place for weeks. So if a chimp discovers a snake, it makes sense for that animal to let everyone else know where [it] is. When [the chimps] saw the model, they would be quite close to it and would leap away, but they wouldn't call," she said.

After initially avoiding the snake, each chimp would approach the snake again. They would make a soft "hoo" sound if they were nearby another chimp who happened to not see the snake.

"Lots of animals give alarm calls and are more likely to give an alarm call [when another animal is present]," Dr. Crockford said.

This situation is different, however, because "they seem tuned, not into who the audience is, but to what the audience knows," she said. Crockford added the findings point to a better understanding how complex communication developed in humans. These findings, Dr Crockford said, provide an important insight into a factor that may have "kick-started" complex communication.

"Now we have seen that these chimps, human's close relatives, seem to recognise ignorance and knowledge in others. And they're motivated to communicate missing and relevant information to that individual. It's one of the things that's been missing from the evolution of language story."