For thousands of years, humans have trained animals to help them. Pigs locate truffles. Dogs sniff for drugs. Dolphins detect underwater mines.
But working in partnership with an untrained wild animal is another thing altogether. And one of the very few species that it has been documented in is the greater honeyguide.
These petite, orange-beaked birds live across sub-Saharan Africa, and they do what their name implies: They guide people to beehives containing honey, which people have a hard time finding on their own and the birds can’t access without being stung to death. For this service, the birds get something in return — the leftover beeswax and larvae, which they eat with abandon. The birds’ unique skill earned them the fitting scientific name of Indicator indicator.
This remarkable human-animal collaboration has been recorded in various spots in Africa where the greater honeyguide lives, and it often involves a honeyguide showing up when it hears people going about their business or whistling. The bird might then hop about and chatter to signal its readiness to lead a honey-hunting expedition. The people then trail the honeyguide, which keeps itself visible by displaying its white tail feathers, until the entire gang arrives at the booty. The people then smoke out the bees, chop open the tree and the hive and harvest rewards for man and bird alike.
But it works a little differently in the Niassa National Reserve of northern Mozambique, a Denmark-sized expanse of remote wilderness that is a crucial habitat for lions and elephants. There live Yao tribe members who depend on honey for trade and nourishment — and who have developed their own unique method of communicating with honeyguides.
When they want to find honey, the Yao call the birds with what a new study calls a “loud trill followed by a grunt: ‘brrr-hm.'” It’s a sound Yao honey hunters learn from their fathers and use under no other circumstances, according to the study, published Thursday in the journal Science. And the honeyguides know exactly what it means, the researchers found.
(Listen here to the call the Yao use to attract honeyguides.)
To figure this out, Claire Spottiswoode, a zoologist at the University of Cambridge and the University of Cape Town, walked through the Niassa forests with Yao honey hunters broadcasting three kinds of recordings: Yao tribe members saying something neutral, such as their own names; the sound of a dove; and the brrr-hm signal.
(Listen here to the other sounds researchers used in the study.)
The special call attracted a honeyguide and led to guiding nearly 67 percent of the time, more than twice as often as the other sounds did. It also resulted in finding a beehive in 80 percent of tests, far more often than the other sounds. Overall, Spottiswoode found, the honey-hunting signal more than tripled the probability of finding a bees’ nest during a 15-minute search.
Put more simply, it’s kind of like a bird-person conversation. The Yao use a special sound that works to elicit honeyguides’ help, and the honeyguides know its meaning.
The call is “a reliable signal to honeyguides that this is a human who’s looking for bees and is more likely to be a good collaborator,” Spottiswoode said in an interview.
She noted that the birds have also figured out that people are the best partners in this endeavor because they know how to use fire. In other areas, for example, chimpanzees also raid beehives, but they sort of “smash and grab” the nest and then “run like hell,” leaving behind wax that would still be full of angry bees very capable of killing honeyguides. The Yao, on the other hand, make a nice bundle of dry wood, wrap it in palm leaves, light it and hoist it on a long pole to the nest. And voila — bee danger averted.
“The crucial point is that honeyguides love wax, whereas humans love honey,” Spottiswoode said. “So there’s no conflict of interest over the reward.”
This isn’t the case everywhere. In Tanzania, for example, hunter-gatherers known as the Hadza also find beehives with honeyguides’ help. But as explained by Atlas Obscura, they often withhold the wax from the birds to keep them hungry — and eager to guide.
In Niassa, the partnership is far more equitable, said Spottiswoode, adding that she thinks the Yao would be shocked to hear about the Hadza strategy. The Yao make a point of rewarding honeyguides by collecting little bits of wax and presenting them on a bed of leaves. “They’ll make a little honeyguide salad,” she said.
But honeyguides, despite their sweet name, also have a dark side. Like some cuckoos and brown-headed cowbirds, they’re brood parasites. That means they don’t build their own nests but instead lay their eggs in other birds’ nests, leaving the other species to raise the honeyguide chick. Afterward, honeyguide mothers often stab the other eggs in the nest to reduce competition for their own chick. If the host birds’ chicks survive that assault, the baby honeyguide takes care of the competition in its own gruesome way: It’s born with two sharp hooks on its beak, which it uses to stab and shake its foster siblings to death.
“They start with this really dark beginning in life,” said Spottiswoode, who has documented the gore. Within a month, their hooks are gone, they leave the nest, and they’re transformed into man’s best honey-hunting friend.
For now, at least. Spottiswoode said the human-honeyguide relationship is breaking down in many parts of Africa as more people find sweetness in sugar at the market rather than in beehives in tall trees. That makes the Yao-bird collaboration all the more amazing, she said.
An earlier version of this article incorrectly reported that greater honeyguides are the only wild species that scientists have documented helping humans. That sort of relationship has also been observed among some populations of wild dolphins that fish with humans.