Gular fluttering dissipates heat: nightjars

1 of 2 Common Nighthawk / Alan Wilson / License

The gular sack of nightjars helps to dissipate heat efficiently by vibrating.

Biomimicry Taxonomy

	Maintain physical integrity >
	Regulate physiological processes >
	Homeostasis

Biomimetic Application Ideas

Moist mesh material that vibrates to create evaporative cooling

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[Collapse all sections] Summary

"An important environmental adaptation for many caprimulgiformes is the ability to withstand high ambient temperature (T_a). Birds of this order are most common in warm climates, and frogmouths, potoos, and nightjars all roost and nest in the open where they can be subjected to long periods of direct sun exposure. In these circumstances, they avoid hyperthermia by using evaporative cooling strategies. Nightjars dissipate heat by gular fluttering, during which the mouth is opened, the rate of blood flow to the buccal area is increased, and the moist gular area is rapidly vibrated." (Fowler and Miller 2003: 225)

"When poorwills are exposed to high temperatures, they increase evaporation of water by initiation of gular flutter and by some increase in breathing rate. Gular flutter supplements evaporation due to respiration, and involves a rapid vibration of the moist membranes of the gular region, driven by the hyoid. The rate of gular flutter in the poorwill is relatively constant and independent of heat load, and evaporation due to flutter is modulated by varying the amount of time spent fluttering, as well as the amount of air moved per flutter." (Lasiewski 1969:1504)

Watch Video (doesn't show gular fluttering, but beautiful!)

Watch Video (gular fluttering of a heron chick)

About the inspiring organism

Caprimulgidae
Caprimulgidae

Organism/taxonomy data provided by:
Species 2000 & ITIS Catalogue of Life: 2008 Annual Checklist

Bioinspired products and application ideas

Application Ideas: In dry hot climates, use of moist mesh material that vibrates to create evaporative cooling could be used to cool housing or building sites.

Industrial Sector(s) interested in this strategy: Air conditioning,

References

Fowler, ME; Miller, RE. 2003. Zoo and Wild Animal Medicine. Philadelphia: W.B. Saunders Co.

Lasiewski RC. 1969. Physiological responses to heat stress in the poorwill. American Journal of Physiology. 217(5): 1504-1509.

Sturkie PD; Whittow GC. 2000. Avian physiology. Ithaca, NY: Cornell University Press. 685 p.

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Comments

Thanks to Emily Harrington for the illustration about how the gular fluttering works.

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