The relationship between scientists and the animals they study in the field is a constantly evolving one -- one that can often cross the boundary between passive observer and integrated player. Jane Goodall’s work with chimpanzees comes to mind first -- as the first researcher to give her subjects affectionate names, she introduced some element of humanity and empathy into her science. 

So it comes as no surprise that things can go the other way. A recent study published in Behavioral Ecology found just that -- a group of samango monkeys who figured out how to use humans for their advantage, themselves crossing the research-subject barrier.

For the study, researchers from Durham University in the UK trekked out to the Soutpansberg Mountains of South Africa, where they set up their study site. Placing feeding buckets filled with peanuts at various heights in trees, the researchers measured how much food the animals took. Naturally, they took less food from the lower buckets, because the risk was higher of ground predators like leopards.

Eva Hejda

But the scientists noted that when they were nearby to the study site, something curious happened. The monkeys, who have seen field researchers in their habitat before, would take a larger portion of food, including food from the lower levels, closer to the ground.

According to the researchers, they became the equivalent of “human shields" against predators -- they felt safer with humans near at hand.

"Researchers are probably perceived as shields against terrestrial predators in particular, and we speculate that the observed patterns may be due to humans passively deterring leopards from the immediate area, rather than playing the role of active sentinels," lead researcher Katarzyna Nowak told Mongabay.

This clever behavior is certainly not consistent for other monkey species -- especially those that are hunted by humans. Naturally, these species are fearful of humans just like samango monkeys are of leopards. But in this case, samango monkeys have provided a rarely-seen phenomenon in the animal kingdom -- similar to the idea of “breaking the fourth wall” in theater, the phenomenon shows that the barrier between animals and the people that study them is still a tenuous one.