(Web Desk) - True partnerships between humans and wild animals are exceptionally rare.
But in parts of Africa, wild birds and humans have struck up an unusual — and sweet — relationship.
Human honey collectors in Tanzania and Mozambique are known to use distinct calls to attract honeyguide birds, which in turn lead the collectors to wild bees’ nests.
It’s a win-win situation: the humans get the honey, and the birds get the beeswax.
But now, a new study in the journal Science adds an intriguing new layer to this symbiosis: Honeyguide birds seem to understand and respond to culturally distinct calls, suggesting a far richer history of understanding between the birds and the hunters.
“This cooperation matters,” said Brian Wood, an evolutionary anthropologist at UCLA and study co-author.
“Honey is an important food for people like the Hadza and Yao today, and honey was also an important food in human evolution.”
Scientists have studied the symbiotic relationship between humans and honeyguides since the late 1980s.
The slight, brown-gray birds with big dollops of white on their cheeks often hover in front of people to get their attention, and early research backed up the honey hunters’ own knowledge that the birds’ flight patterns can reveal where bees' nests lie.
More recently, researchers confirmed that hunters who make a specific call to the honeyguides, as opposed to making any noise at all, more than triple their chances of being led to a nest.
But the exact nature of that specific call varies across communities. In northern Mozambique, for example, the Yao people attract honeyguides with a drum roll-like sound, while in Tanzania, Hadza honey foragers melodically whistle to attract the birds.
In the new study, the researchers sought to find out if the birds learn to respond to different cultures’ signals, or if they respond to all signals just the same, Wood explained.
So Wood and his colleagues set up speakers, and in each region, the team played the Yao’s call, the Hadza’s whistle and an arbitrary human sound, like a hunter calling out their name.
In Tanzania, birds were more than three times more likely to respond to their local community’s whistles than either the Yao’s drum-roll or arbitrary human noises.
Similarly, Mozambique honeyguides were nearly twice as likely to respond to their local calls, the researchers found, strongly suggesting that the birds learned the cultural traits of the local peoples.
The researchers aren’t sure why the Hadza and Yao honey hunters use different signals in the first place, though differences in their lifestyles might play a role. Hadza honey hunters also hunt larger game while out foraging. Their whistles might attract the birds but not spook their prey, they say, maximizing their chances of success on both fronts.
Yao collectors only pursue honey, and their loud trills could actually be useful in scaring off dangerous animals, like elephants or lions. Over time, these cultural differences have become set for both humans and birds, the researchers suggest, as any deviation from them could result in less honey for the hunters and less honeycomb for the birds.
“The human-honeyguide partnership is one example of a bird that can adjust, through learning, to human cultural diversity,” said Wood.
“It is really important to document mutual dependencies between different human communities and diverse animal species, especially in the face of rapid anthropogenic environmental change.”