Lonchophylla robusta: feeding (overview).
Feeding L. robusta (overview), illustrating the constant contact between the tongue and nectar throughout the entire visit (nectar level 20 mm; time expansion 50 x) - (Video S2 of: 10.1126/sciadv.1500525).
Bat drinks using ‘tongue-pump’ trick
Unique mechanism is an alternative to lapping up liquid.
Nature 25 September 2015 doi:10.1038/nature.2015.18434
http://www.nature.com/news/bat-drinks...
Reference
Nectar uptake in bats using a pumping-tongue mechanism
Science Advances 25 Sep 2015: Vol. 1, no. 8, e1500525, DOI: 10.1126/sciadv.1500525
http://advances.sciencemag.org/conten...
Abstract
Many insects use nectar as their principal diet and have mouthparts specialized in nectarivory, whereas most nectar-feeding vertebrates are opportunistic users of floral resources and only a few species show distinct morphological specializations. Specialized nectar-feeding bats extract nectar from flowers using elongated tongues that correspond to two vastly different morphologies: Most species have tongues with hair-like papillae, whereas one group has almost hairless tongues that show distinct lateral grooves. Recent molecular data indicate a convergent evolution of groove- and hair-tongued bat clades into the nectar-feeding niche. Using high-speed video recordings on experimental feeders, we show distinctly divergent nectar-feeding behavior in clades. Grooved tongues are held in contact with nectar for the entire duration of visit as nectar is pumped into the mouths of hovering bats, whereas hairy tongues are used in conventional sinusoidal lapping movements. Bats with grooved tongues use a specific fluid uptake mechanism not known from any other mammal. Nectar rises in semiopen lateral grooves, probably driven by a combination of tongue deformation and capillary action. Extraction efficiency declined for both tongue types with a similar slope toward deeper nectar levels. Our results highlight a novel drinking mechanism in mammals and raise further questions on fluid mechanics and ecological niche partitioning.