This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: A northern gannet scans the sea for fish from 100 feet (30 meters) in the air. Upon seeing a school, it pitches its body into a nosedive, somehow breaking the surface at 70 miles per hour (113 kilometers per hour) without breaking its neck.
This daring maneuver seems to defy the laws of nature, but it's standard hunting behavior for plunge-diving seabirds. A University of Washington study published Oct. 12 in the Anatomical Record shows that gannets and boobies have unique morphological adaptations that allow them to survive impact. Several of their neck vertebrae are joined by an additional contact surface that helps stabilize the cervical column.
The overall shape of the vertebrae is also stockier than that of other birds' vertebrae. "We wanted to figure out what makes gannets so special, so good at diving, and looking at their biology helped us understand how they can survive these impacts," said senior author Bart Boom, a postdoctoral scholar at the UW's Friday Harbor Labs. The ecological record shows repeated instances in which birds develop physical traits in response to their environment.
Charles Darwin was among the first to record this in the 1830s—in finches on the Galápagos Islands—and researchers are still discovering new examples today. The connection between beak shape and foraging behavior is well documented, but the link between neck structure and feeding has received less attention. The UW researchers began studying the mechanics of plunge-diving years ago.
Gannets are built to withstand immense pressure on the head and neck that compresses the cervical column. Engineers typically favor short and fat structures for things built to tolerate compressive force, but these birds have long, slender necks with segmented vertebrae. Gannet necks have 15 stacked vertebrae that bend slightly in an S-curve.
Previous studies have shown that the muscles surrounding their vertebrae help lock them in place to prepare for impact, but few studies have looked at the actual morphology of diving birds' necks. To do so, the researchers collected specimens of diving birds and nondiving birds from the Burke Museum. The team performed CT scans to create detailed three-dimensional models of the cervical vertebrae and then analyzed the images with geometric morphometrics, a statistical method for studying biological samples that establishes landmarks for comparison.
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