The Skeleton Revealed: An Illustrated Tour of the Vertebrates

1. What they did

Steve Huskey, a biologist at Western Kentucky University, presents a photographic tour of vertebrate skeletons. He explains that a skeleton protects organs, stores minerals, makes blood cells and, above all, works as a system of levers that muscles pull on to create movement. Because movement underlies behaviour, the skeleton can tell us how an animal feeds, moves and defends itself, for living species and for fossils such as dinosaurs.

Each carcass (donated by zoos, aquariums, fish farms and private donors) was set in a life-like pose, cleaned by flesh-eating beetles and carefully rebuilt. Many are posed in action: striking, swallowing, fighting or holding prey. Each photograph comes with a short account of the species’ range, habitat, diet, behaviour and the skeletal features behind it.

2. What they found

The book is a survey, not a study, but its accounts include many details of how skeletons shape behaviour. Examples:

• Feeding: the slingjaw wrasse shoots its jaws further than any other animal; pythons “walk” their skull over prey using movable rows of teeth on the roof of the mouth; boomslangs open their mouths nearly 180 degrees to reach their rear fangs.
• Bones as food: leopard tortoises have a keratin beak strong enough to bite through old bones, which they eat for calcium.
• Claws and feet: the lesser anteater’s front claw is so long that they walk on the outside of their feet to avoid digging it into their own palms, and use it to tear open ant hills and termite mounds.
• Digging and travel: eastern moles have an extra wrist bone, the “mole’s thumb,” that works like a sixth finger for shovelling; four-toed hedgehogs may travel up to 5 miles in a night.
• Hunting and fighting: red-tailed hawks drive prey such as grey partridges to the ground with talons and wings, then often eat part of it there before carrying it to a perch; rival wild turkey males fight with the sharp spurs on the backs of their legs.
• Defence: opossums, porcupines, hedgehogs and tamanduas each have their own ways of facing predators, from feigning death to quills and slashing claws.

3. What they concluded

The author concludes that by simply examining the skeletons of living vertebrates, one can learn a remarkable amount about how they survive: who their ancestors were, what they eat and how they catch it, and whether they fly, run, jump, burrow, climb or swim. The evolution of the skeleton remains a source of wonder.

6. Other technologies, skills or innovations

• Carcasses posed in life-like positions, cleaned by flesh-eating beetles and reconstructed bone by bone, then photographed, with photo editing by Tressa Tullis and Matt Tullis.

7. Implications for conservation (from the paper)

• Several accounts describe threats from people: overharvesting for the pet trade (the Hog Island boa, nearly removed from the wild in the 1980s and since rebounding) and for fur (chinchillas, still critically threatened in the wild); habitat loss; and released pets becoming invasive (lionfish in the western Atlantic, Burmese pythons, African clawed frogs).