How Kingfishers May Help Us Fight Alzheimer’s

The long-term effects of repeated concussions have become well known. Tangles of tau protein build up in the brain after repeated head impacts. A person with repeated concussions may experience ongoing headaches, problems with concentration and memory, and even loss of physical skills such as maintaining one’s balance. Some people develop chronic traumatic encephalopathy (CTE), a progressive and fatal brain disease which is also associated with the development of Alzheimer’s.

How then can kingfisher birds repeatedly plunge dive for fish without suffering any consequences? Flying at about 25 miles per hour as they hit the water, plunge-diving kingfishers put enormous pressure on their beaks, heads and brains. The birds dive repeatedly, smacking their heads into the water in ways that would cause concussions in humans. So there must be something that protects them from the consequences of repeatedly hitting their heads against a hard surface.

Shannon Hackett, an evolutionary biologist at the Field Museum in Chicago, started worrying about the effects of repeated hits on the human brain when her son began playing hockey. In a fortunate coincidence, evolutionary biologist Chad Eliason joined the museum around the same time, to study kingfishers and their plunge-diving behavior. The two collaborated to research how the birds protected their brains. They analyzed the genes of 30 kingfisher species, some that plunge dive and others that don’t. They wanted to find out if different diving species had evolved similar genetic changes to arrive at the same behaviors.

They found a convergence on beak shape, making plunging kingfishers’ beaks long and pointy, allowing them to dive more effectively into the water. They also found a tweak in the gene that holds the instructions for making the tau protein. When functioning normally, tau helps to stabilize cell structure so this change could help the birds adapt to diving. It seems that the same tau protein which can cause such problems in humans has been used in a different way to help mitigate hard impacts in kingfishers.

The next steps are to test how these genetic mutations and resulting proteins, particularly tau, offer brain protection for the diving species. Eventually, the results could possibly be applied to developing protective strategies against concussions and brain injury for humans.