From Skeletor to the Danse Macabre, from Army of Darkness to ossuaries and holy relics – despite being largely hidden in life, skeletons are some of the most recognizable structures that nature has produced. Science writer Brian Switek has written a sizzling little book with Skeleton Keys* that delves into both the biological and cultural significance of human bones, showing them to be more than just a powerful reminder of death and mortality.

Switek starts off with a potted evolutionary history of the skeleton, taking the reader all the way back to the Cambrian, some 455 million years ago. The small fossils of Pikaia gracilens are some of the earliest evidence we have of the starting point of skeletal evolution. Looking for all the world like a small worm, it was one of the first creatures to possess a notochord, a cartilage-like structure that is the precursor of the backbone. (For a more technical exposé of that borderline between vertebrates and invertebrates, see my review of Across the Bridge: Understanding the Origin of the Vertebrates.)

He then hops, skips, and jumps to other significant milestones; fossils of the fish Entelognathus primordialis show the transition to jawed fish, while Tiktaalik roseae (see Your Inner Fish: The Amazing Discovery of Our 375-Million-Year-Old Ancestor) shows the transition of vertebrates moving onto land. He considers protomammals, the cynodonts, whose offspring lived through the age of the dinosaurs, and the primordial primates, noting how the changing skeleton acquired more and more traits we now think of as human.

This part is far from a complete overview of the evolution of skeletons (for that, see e.g. Skeletons: The Frame of Life), but that was never the intention. It does allow Switek to exercise his funny bone, wondering whether without the evolution of jaws the book and movie would instead be known as Pharyngeal Slit, or comparing the earliest invasion of land by plants to a prehistoric salad bar. At the same time, he is keen to correct misunderstandings about evolution: “It is easy to make categorical divisions between humans and apes when extinction has removed your ancestors”. Similarly, as Tiktaalik shows, any true invasion of land did not coincide with the origin of fingers and feet, with fish evolving into amphibians only millions of years later. This should do away with the misconception of evolution being goal-oriented (beyond, you know, making it to the next generation).

“Without the evolution of jaws, would the book and movie instead be known as Pharyngeal Slit?“

But we cannot dwell here any longer. Bone as living tissue is fascinating, and Switek introduces the physiology, with osteoblast cells continuously forming new bone while osteoclasts break it down again. Something that goes off kilter when astronauts spend months in space and lose bone mass. That makes hibernating bears all the more of a miracle, how do they not lose bone mass? Switek has the answer. Bone can be moulded in life, as seen by cultures around the world that change the shape of infants’ skulls, while in death it retains a personal history of disease and injury. Archaeologists are becoming increasingly skilful at elucidating these stories (see for example Injury and Trauma in Bioarchaeology: Interpreting Violence in Past Lives and Skeletons in Our Closet: Revealing Our Past through Bioarchaeology).

At this point Switek transitions seamlessly into the cultural significance of bone, and how especially skulls have become emblems of death. Neanderthals appear to have been much more sophisticated than we have long given them credit for, as evidenced by burials (see my review of The Smart Neanderthal: Cave Art, Bird Catching, and the Cognitive Revolution), while his recounting of the exhumation of Richard III’s skeleton in a Leicester car park in 2012 is a fascinating archaeological detective story.

A far darker chapter that Switek tackles with panache is the heritage of anthropology. The pseudoscience of phrenology (where measurements of the bumps on a skull supposedly predicted someone’s mental capacities and traits) was long used to justify white man’s superiority. As he mentions, anthropology may not have invented racism, but it certainly fueled it through the 19th and 20th century. Switek is deeply troubled by the resurgence of the idea that race is biologically meaningful. As has been documented at length, there is more variation within populations than between populations, and the overlap between what we thought of as races is enormous (see strident takedowns in The Myth of Race: The Troubling Persistence of an Unscientific Idea and Superior: The Return of Race Science).

“[…] anthropology may not have invented racism, but it certainly fueled it through the 19th and 20th century.”

This naturally leads on to the literal skeletons in the closets of many research collections. Lance Grande, a curator at Chicago’s Field Museum, dedicated a chapter to this in his book Curators: Behind the Scenes of Natural History Museums. The repatriation of old skeletons to for example Native American tribes, for whom the bones of the deceased hold particular spiritual significance, is becoming more commonplace. But not all museums are going along with it, as evidenced by Switek’s story of the skeleton of the Irish Giant Charles Byrne, who is still on display. Another one of those eye-opening tidbits in the book is his peek at the online trade in human bones on platforms such as eBay and Etsy (who have since cracked down on it), and now Instagram. You are far better off building your own.

Each chapter opens with a drawing from the 1733 book Osteographia or the Anatomy of Bones. These are lovely, and my only bone of contention (sorry) is that there aren’t more illustrations in the book. I would have loved to see some photos included, as Switek describes many wonderful things. For that, readers will have to turn to, for example, the work of palaeoartist John Gurche (see my review of Lost Anatomies: The Evolution of the Human Form) or, two of my personal favourites, Evolution in Action: Natural History Through Spectacular Skeletons and Skulls: An Exploration of Alan Dudley’s Curious Collection. Other slightly less spectacular but still noteworthy books are The Skeleton Revealed: An Illustrated Tour of the Vertebrates and Skeletons: The Extraordinary Form & Function of Bones.

Skeleton Keys is a multifaceted exploration of bones and their biological and cultural importance that is very absorbing. Far from a macabre gawk-fest (Skeletons! Eek!), Switek capably handles a range of serious topics, smoothly transitioning between them. The narrative sizzles, whether it is with witty jokes or genuine ire at the disrespect to bones and the questionable ideas they are used to prop up. An incredibly enjoyable book that comes highly recommended.

*Note that the book is published in Europe by Duckworth in paperback with a completely different title: The Secret Life of Bones: Their Origins, Evolution and Fate.

Disclosure: The publisher provided a review copy of this book. The opinion expressed here is my own, however.

The Secret Life of Bones paperback / Skeleton Keys hardback

Other recommended books mentioned in this review:

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