Gannets are large seabirds that plunge toward the ocean’s surface at speeds of up to 190 kilometers per hour (118 mph). When a gannet hits the water, the impact may exceed 20 times the force of gravity. How are gannets able to survive and repeat such formidable dives?
Consider: Before the gannet hits the water, it stretches its wings behind its body, making it streamlined like an arrow. It also draws a protective membrane over its eyes and inflates organs in its neck and chest that function as airbags to cushion the impact.
As the gannet pierces the ocean’s surface, its beak, head, and neck form a cone. This shape evenly distributes the force of impact on the gannet’s sturdy neck muscles. In an instant, the gannet refocuses its eyes for underwater vision.
How deep can the gannet dive? The bird’s momentum can take it to a depth of almost 11 meters (36 ft), but it can continue its descent by flapping its half-folded wings and kicking its webbed feet. Actually, gannets have been spotted diving to depths greater than 25 meters (82 ft) below the ocean surface. When finished diving, a gannet floats effortlessly to the surface, ready to fly again.
Watch gannets dive
Researchers designed bionic gannets to assist in search-and-rescue operations. These robots were expected to fly, dive into the water, and become airborne again. However, during prototype trials, one robot broke several times as a result of hitting the water too violently. This led the researchers to conclude that their prototype was “not good at plunge diving compared to the gannet.”
What do you think? Did the gannet’s diving ability evolve? Or was it designed?