Richard Wrangham of Harvard University's Department of Human Evolutionary Biology said that the traditional understanding of the guiding behavior of greater honeyguides was that it had co-evolved, not with humans, but with another species: ratels (honey-badgers). This has not been proven, however.
"So that raised the possibility," Wrangham said, "that the mutualistic relationship between honeyguides and humans is a result of direct co-evolution between those species. The new paper supports that view."
It was previously thought that the birds would respond to any unusual noise, such as car engines.
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"The new finding shows that honeyguides pay special attention, not just to sounds made by humans, but specifically to the sounds that are designed by humans to attract honeyguides," Wrangham said.
Honey is not just a sweet snack, either. He shared that it sometimes supplies African hunter-gatherers with up to 80 percent of their calories per month. Greater honeyguides have therefore been benefitting our survival for ages, and vice versa.
Spottiswoode however said that "the honeyguide-human relationship has already largely vanished from many parts of Africa, so our opportunities fully to understand this relationship are fast disappearing."
She believes that is one of many reasons why Niassa National Reserve is so important.
"It's a protected area the size of Denmark," she said, "with globally important populations of elephant, lion, wild dog and other wildlife, but it is under threat from many quarters, including elephant poaching and gold mining."