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Hummingbird tongues are elastic micropumps
Alejandro Rico-Guevara1, Tai-Hsi Fan2, Margaret A Rubega3
1Department of Ecology and Evolutionary Biology, University of Connecticut, Storrs, CT 06269, USA Instituto de Ciencias Naturales, Universidad Nacional de Colombia, Bogotá DC, Colombia a.rico@uconn.edu.
Proceedings. Biological Sciences
|August 21, 2015
Summary
Hummingbird tongues utilize an elastic micropump mechanism, not capillarity, to rapidly collect nectar. This novel fluid transport system allows for faster nectar extraction, explaining their efficient feeding behaviors.
Area of Science:
- Fluid dynamics
- Biomechanics
- Zoology
Background:
- Pumping is a fundamental natural process crucial for fluid transport.
- Hummingbirds are known for their rapid nectar feeding, but the exact mechanism has been debated.
Purpose of the Study:
- To investigate and elucidate the fluid transport mechanism of nectar uptake in hummingbird tongues.
- To challenge the prevailing theory of capillarity in hummingbird nectar feeding.
Main Methods:
- High-speed videography was employed to film tongue-nectar interactions in 18 hummingbird species.
- Analysis focused on tongue deformation, fluid filling, and the absence of menisci formation.
Main Results:
- Hummingbird tongues compress upon extrusion and rapidly expand upon nectar contact, filling the grooves.
- The study observed an elastic micropump mechanism driven by tongue re-expansion, not capillarity.
- Nectar is loaded into the tongue grooves an order of magnitude faster than capillarity would allow.
Conclusions:
- The long-held theory of capillarity in hummingbird tongue nectar feeding is falsified.
- Hummingbird tongues function as elastic micropumps, enabling rapid nectar uptake.
- This mechanism explains the high nectar extraction rates observed in hummingbirds, aligning with their rapid feeding.
