Proc. Natl Acad. Sci. USA http://doi.org/brwm (2016)

Seabirds are notorious for plunge diving at seemingly break-neck speeds. But does hunting like this really pose a threat to their slender necks? And might humans be able to withstand similarly treacherous descents? Brian Chang and colleagues sought to find out by developing a mechanical understanding of neck stability during plunge diving.

The team focused on two seabird species that both endure strong axial forces when they dive, despite having distinctly different styles. A slender body subject to axial forces should buckle, but seabirds only injure themselves diving when they collide with other birds. To make sense of this, Chang et al. conducted experiments on a model seabird made of a long, thin elastic beam attached to a rigid cone, and performed a linear stability analysis to predict the buckling transition.

Their analysis suggested that the birds' neck muscles and morphology render them ideally suited to plunge diving at high speeds. A similar consideration of humans diving feet first found that the compressive forces for comparable speeds would be far too high for our bodies to endure.