Two unrelated groups of nectar eaters, hummingbirds and sunbirds, evolved different techniques to slurp the sweet liquid from flowers. The tongue suctioning employed by sunbirds is unique among vertebrates.
While we often think of hummingbirds as sucking nectar from flowers, they’re not sucking the way we suction juice through a straw — they’re really sponging up nectar with their tongues and squeezing the juice into their mouths by compressing their tongues with their beaks.
Humans are naturally able from birth to use mouth suction to draw in liquid, but it’s not easy if you don’t have lips to create an air-tight seal, and few animals besides mammals have lips.
But a new study by current and former University of California, Berkeley biologists found that sunbirds, the African and Asian counterparts of the nectar-sipping hummingbirds of the Americas, do use suction to slurp nectar. They’re the first animals known to employ their tongues to suction up liquids.
The results highlight the fact that nature often finds different solutions to similar problems — in this case, how to use a long, tubular and often curved beak to extract sustenance from deep within a flower. It’s referred to as convergent evolution.
“It’s just a really amazing example of the power and beauty of convergent evolution, where in nature we have two organisms filling the same ecological role, but when you look in detail, they’re achieving that outcome in two completely different ways,” said Rauri Bowie, UC Berkeley professor of integrative biology and a study author. “In our case, we’re seeing a mechanism that is completely novel in vertebrates and a remarkable example of innovation.”