Some bats do not suck, gulp or lap liquids, but instead drink in a way that has never been documented before in any animal.
The grooved tongues of certain bats appear to never separate from the liquid nectar that they feast upon, but instead transport the drink like a conveyor belt - up the tongue and right into the bat's mouth.
The findings are published in the latest issue of the journal Science Advances.
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"Our results highlight a novel drinking mechanism in mammals," wrote lead author Marco Tschapka, of the University of Ulm and the Smithsonian Tropical Research Institute, and his colleagues.
The researchers used high-speed cameras to observe bats that were trained to obtain nectar from artificial test tube flowers. The nectar consisted of a honey-water mixture that was irresistible to the bats.
"All bats visited the feeders in short hovering flights rarely lasting longer than a second," according to the scientists.
The speed with which they drink explains why their unique way of acquiring liquids was never noticed before.
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The high-speed cameras, however, revealed that grooved-tongued bats with a thirst for nectar lowered their tongues into the faux flowers and did not move them during the entire visit.
Bats with hairy appendages on their tongues, conversely, drank the honey mixture by moving their tongues in short, lapping movements, similar to how a cat laps up liquids.
Both types of bats co-exist in the neo-tropics, from southern Mexico to Peru, Bolivia and Brazil.
"This coexistence," according to the scientists, "suggests that nature offers fitting niche options for both."
They theorize that the bats specialize in drinking from different types of flowers that produce nectar of varying viscosity.
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"Nectar from bat-visited flowers is generally rather dilute, but sugar concentrations range between 4 percent and nearly 30 percent," Tschapka and his team explained. "Although this is far from the extremes found in nature, nectar of low sugar concentration and viscosity might be more easily harvested by the pumping mechanism (conveyor belt method) than nectar of high sugar concentration and viscosity."
The study raises questions about fluid mechanics in general, because the precise way in which the bats' conveyor belt-like tongue works remains unknown for now. Once that is figured out, there might be applications for humans, foreseeably leading to new technologies for medical devices, machinery and more.