Hummingbird tongues are elastic micropumps (Video 4)
Expansive filling in a variety of hummingbird species. Slow motion (215-280 times slower than real time) videos of a Crowned Woodnymph (Thalurania colombica), a Short-tailed Woodstar (Myrmia micrura), an Indigo-capped Hummingbird (Amazilia cyanifrons), and a Black-chinned Hummingbird (Archilochus alexandri, courtesy of Don Carroll) drinking nectar. Notice the expansive filling of the tongue in all videos. The footage was taken at 400-800 fps and the timers are displaying in milliseconds (Video S4 of: 10.1098/rspb.2015.1014).
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
Hummingbird tongues are elastic micropumps
Proc. R. Soc. B. 282, 20151014, 19 August 2015, DOI: 10.1098/rspb.2015.1014
http://rspb.royalsocietypublishing.or...
Abstract
Pumping is a vital natural process, imitated by humans for thousands of years. We demonstrate that a hitherto undocumented mechanism of fluid transport pumps nectar onto the hummingbird tongue. Using high-speed cameras, we filmed the tongue–fluid interaction in 18 hummingbird species, from seven of the nine main hummingbird clades. During the offloading of the nectar inside the bill, hummingbirds compress their tongues upon extrusion; the compressed tongue remains flattened until it contacts the nectar. After contact with the nectar surface, the tongue reshapes filling entirely with nectar; we did not observe the formation of menisci required for the operation of capillarity during this process. We show that the tongue works as an elastic micropump; fluid at the tip is driven into the tongue's grooves by forces resulting from re-expansion of a collapsed section. This work falsifies the long-standing idea that capillarity is an important force filling hummingbird tongue grooves during nectar feeding. The expansive filling mechanism we report in this paper recruits elastic recovery properties of the groove walls to load nectar into the tongue an order of magnitude faster than capillarity could. Such fast filling allows hummingbirds to extract nectar at higher rates than predicted by capillarity-based foraging models, in agreement with their fast licking rates.