How Diving Kingfishers Avoid Concussions at High Speeds

According to a recent study, genetic adaptations in kingfishers could potentially provide some protection when these birds perform a beak-first dive into water for catching fish. The researchers discovered alterations in genes associated with blood vessel development, retina functionality, and brain operation in certain kingfishers known for their diving techniques. These changes might shield them from potential harm during their dives. However, it is still uncertain as to how these genetic adjustments safeguard the birds.

Kingfishers can reach up to 40 kilometers per hour when diving, causing immense pressure on their heads, beaks, and brains that can cause potential harm. Shannon Hackett, an evolutionary biologist at the Field Museum in Chicago, said that these birds hit their heads against hard surfaces so often that it could lead to concussions in humans. Therefore, there must be some factor protecting them from these potentially harmful effects.

Hackett's interest in how these birds protect their brains developed while working with a hockey team and becoming concerned about repeated head impacts on the human brain. Around the same time, evolutionary biologist Chad Eliason also joined the museum to study the plunge-diving behavior of kingfishers.

In their study, Hackett, Eliason, and their team analyzed the genome of 30 different kingfisher species, some dive and some don't. The birds used for analysis were collected from around the world. They noticed that different diving species might have developed similar genetic changes leading to these behaviors. However, it was unclear whether this was through genetic convergence, similar to the loss of flight in certain bird species, or the independent development of echolocation by bats and dolphins.

Among 93 genes showing changes, one stood out: a gene responsible for tau protein production. This protein helps stabilize cell structure and might assist birds in adapting to diving. In humans, tau is linked to neurodegenerative diseases like Alzheimer's and shows up in clumps in brain tissue after multiple concussions.

However, arguably, the type of genetic analysis done in this study could be difficult. Some of the convergent genes identified might resulted from chance and not necessarily related to the evolution of diving behavior. More extensive research is required to distinguish which genetic changes are relevant to diving.

The researchers are now planning to test how these genetic mutations, specifically tau, function in kingfishers and how these genetic differences in diving species might provide protection. If similar studies offer insight into how these birds shield their brains, the findings could potentially contribute to the development of protective strategies against concussions and brain injuries in humans. However, that scenario is quite far fetched.

Indeed, there's a long journey ahead in understanding how the genetic modifications are reflected in the natural world, according to Hackett. They are just starting to explore those questions.

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