Book Review: Feathers, by Thor Hanson

Book subjects come in waves; the publishing world is now full of books on feathers, but this may well be the best. Thor Hanson, a field biologist, claims that the subject chose him. If so, it chose well; I love nothing better than scientists who can write. Hanson’s book covers every aspect of feathers—evolutionary, structural and functional, and finally cultural, showing all the ways that humans as well as birds use them. He ranges in time from the lithographic shale of the Jurassic to the present, and geographically from China to Maine to Las Vegas.

All birds have feathers; do feathers make a bird? Not quite. Hanson travels to an unlikely museum in Thermopolis, Wyoming, to see a fossil Archaeopteryx that may be even better than the type specimen from Germany; he confirms, as Huxley suspected in the 19th century, that despite its “advanced” feather structure it is more dinosaur than modern bird. One of the most interesting puzzles in the book is that the debate about birds being dinosaurs persists. Though Hanson is scrupulously fair, almost all scholars except one stubborn holdout, and virtually all the evidence, say yes. The Chinese fossil quarries have now yielded evidence that dinosaurs molted like birds and, although it is little publicized, that there are even older feathered dinosaurs than Archaeopteryx. One such is Anchiornis, which had a crested head like a jay. Bipedal dinosaurs provide a different starting point for flight than all the other quadrupedal “trees-down” flying animals. Pre-existing feathers in dinosaurs provided an alternative to the membranes of all other flying vertebrates. The “Birds Are Not Dinosaurs” proponents are beginning to look like Creationists.

Hanson’s runs through “engineering” and culture are even more fascinating and less familiar. To introduce the subject of “biomimetics,” the mimicking of biological structures and processes, he visits a falconer who skydives with his Peregrine Falcon; his remark about the hard edges on falcons’ feathers, more pronounced than those of other raptors, had me nodding in agreement. He makes the astonishing suggestion that covering aircraft wings with featherlike structures might improve flight efficiency by as much as 15 percent by eliminating drag.

He shows us how down is still more efficient as an insulator than synthetics, despite its vulnerability to wetting. A kinglet weighs less than five grams (a fifth of an ounce), of which feathers make up 7 percent: in the sub-zero Maine winter the difference between the outdoor air temperature and the bird’s internal warmth can be as large as 140 degrees Fahrenheit. Even cormorants “allow” only the outer part of their feathers to get wet to negate their natural buoyancy; the inside stays dry to keep them warm.

He passes on to the myriad human uses of feathers—aesthetic, utilitarian, horrifying, even inspirational. (As an aside, he makes the same complaint as virtually every naturalist I know: “this activity [picking up feathers] is technically illegal in the United States—most wild birds, as well as their nests, eggs, and feathers, are protected from any harassment or handling under the Migratory Bird Act.”)

It was not always so, sometimes to the birds’ detriment. The most valuable cargo on the Titanic was feathers for the milliner’s trade, worth more than $2.3 million in today’s currency. The cloak of King Kamehameha of Hawaii required the golden feathers of 80,000 now-extinct mamo honeycreepers. More benignly, South Africa practically committed its economy to Ostrich breeding in the early 20th century, backing a seriocomic expedition to import higher-quality Barbary Ostriches from North Africa only to have the market collapse. There is even a chapter on quill pens, once considered the best of all writing implements. A few eccentric artists still use them. In the 1990s, some monks commissioned a quill-drawn illuminated Bible from calligrapher Donald Jackson, which took him and his coworkers 13 years to complete; it was the first since Gutenberg.

Hanson concludes with wonder: “The exploration of natural miracles is a fundamentally open-ended and curiosity-driven enterprise. It reminds us that science is not always about the answers; it’s about the questions.”