Güçlendirilmiş omurlar dalışçı deniz kuşlarının boynunu koruyor

Gannets and boobies can strike the sea headfirst at roughly 70 miles per hour without breaking their long necks. University of Washington researchers investigated how their anatomy survives this compression. They CT-scanned museum specimens from birds with different feeding styles and built three-dimensional models of the neck vertebrae. Compared with non-divers, plunge-diving birds had shorter, wider and thicker vertebrae. Gannets and boobies also possessed an extra contact surface, called an articular facet, between several vertebrae near the top of the neck. The researchers propose that these facets limit backward bending when a bird hits the water at an angle and direct the load down the cervical column. Smaller kingfishers lacked the additional facet but independently evolved similarly blocklike vertebrae. Despite differences in size, the groups experienced comparable force per unit of neck area. The anatomical link may eventually help palaeontologists recognize plunge-diving behaviour in fossil birds, although the team still needs to examine force transfer in greater detail.