Defying Gravity: Bird flight, culture and evolutionary grooves

In the final episode of the season, Susan Mathews speaks with Antone Martinho-Truswell, a fascinating behavioural ecologist, Operations Manager at the Sydney Policy Lab, and Research Associate at the School of Life and Environmental Sciences at the University of Sydney, Australia. His Substack is called The Village Green and he is author of The Parrot in the Mirror: How evolving to be like birds made us human (2022). The book, and this episode, considers the parallels between the ‘evolutionary grooves’ of the extremely advantageous traits of humans and birds—the former, by becoming the cultural ape, and the latter through flight. 

Antone explains how one trait that is advantageous leads to a number of adaptations that support it. For example, how human babies are born underdeveloped, and humans have cultures that care for children for a long time in order to support the big brain that we need to grow. Taking us through the evolution of birds, Antone describes how, in dinosaurs like T-Rex, small raptors and Archaeopteryx, scales evolved into feathers which smaller dinosaurs probably began to take advantage of with glides and long leaps. And, over time, the bodies of these creatures became entirely specialised for flight. 

They spoke about relative lifespans. Birds live two to ten times as long as mammals of a similar size. The reason is flight. The most obvious advantage is that it’s much easier to escape predators, but birds live longer even when there are no predators around. This is because of K-selection and r-selection. K-selection is a live-slow-die-old strategy, and r-selection a live-fast-die-young strategy. An adaptation like flight starts a virtuous cycle where, since it is much more likely that a bird makes it to the next breeding season, evolution selects traits that enable it to live longer. 

Movement itself, Antone stresses, is a pretty impressive biological feat. While microorganisms and water-dwelling creatures like coral are bathed in the medium that sustains its life, and plants are rooted in a life-sustaining substrate, wrapping all of the incredibly complex chemical reactions of life in a waterproof bag like a dog or a human is incredible. And then adding the third dimension of flight is a difficult feat because the animal has to fight gravity itself. The evolutionary advantage is huge because it's rare, and it’s rare because it's hard to do. 

But such a drastic advantage can also have other implications. Antone’s article Empire of Flight in Aeon, considers why, even though birds have a lot of the same raw materials for a robust and complex culture—intelligence, communication, long overlapping lives, knowledge passed down through the generations—they have not developed one. Evolution never aspires to anything, only responds to inadequacy, and so, he hypotheses, birds don’t need culture because flight is such a powerful adaptation. The more advantageous the adaptation, the less likely it is that a different way of life evolves. 

Similarly, in humans, while there are some incremental changes to our genes, our complex culture, with its welfare, science, and other innovations, has taken away the pressure to do things differently. Even if there is an apocalyptic event that takes away all of our technology, we're still going to have all of the abstract components—like writing and money—that give us significant advantages. But just as this capacity lets us build concepts like democracy, it also enables us to build complex concepts like ‘enemies’ and ‘hate’ in ways that few other creatures can. 

Finally, while narrow sustainability—energy consumption, resource use—is important, Antone persuades us to think of broader sustainability. We need to consider the physical space and the resources that we and our cities use, and, rather than fencing in nature, find ways to live that are continuous with the rest of nature. 

This season of The Subverse has been produced by Tushar Das. A special thank you to Julian Wey for access to his Qumquat studio and Daniel Schwenger for his assistance. 

 

More about the guest:

Antone Martinho-Truswell’s work focuses on animal minds and learning, and on human behaviour and interaction with the natural world. He is particularly interested in birds and cephalopods, intelligent species whose evolutionary history differs dramatically from that of mammals. His academic work has been published in Science, Proceedings of the Royal Society B, Current Biology and Animal Behaviour and covered in The New York Times, The Atlantic, The Times and New Scientist, among others. He also writes on longstanding questions in biology and animal behaviour for Aeon and the BBC. You can find him on Instagram @stjosephwoodworks.