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Darwin, the crowdsourcer: Friends and family helped the naturalist form his famous theory

Darwin’s Backyard: How Small Experiments Led to a Big Theory

James T. Costa
461 pp.
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At Down House in Kent, Charles Darwin is instructing his manservant Parslow to lower another dead pigeon into a foul-smelling pot. It is February 1856. Darwin is 47 years old. Endlessly curious, he has begun to suspect that the skeletons of different pigeon varieties will support his secretly held ideas about how species are related and have changed throughout history.

As James T. Costa details in the excellent Darwin’s Backyard, Darwin found the evidence he was searching for in the pigeon bones. He found it elsewhere, too: in the complex pollination of orchids and the social behaviors of ants, in the morphology of barnacles and earthworms, and in the movements of carnivorous plants. The evidence he collected around the world and in the tangled bank near Down House would go on to make the 1859 publication of On the Origin of Species possible.

Things began inauspiciously enough. In 1831, inspired by the works of naturalist Alexander von Humboldt, Darwin—a medical school dropout—embarked on a 5-year voyage aboard the HMS Beagle.He was 22 years old, was constantly seasick, and was Captain Fitzroy’s third choice for the position of ship’s naturalist. But Darwin’s keen mind questioned everything. He saw—and recorded—it all, writes Costa, a professor of biology at Western Carolina University.

After his return, Darwin’s ideas about evolution began to formulate, but he knew that he needed evidence to support them.

Whenever possible, he crowd-sourced his data, enlisting the help of his children (he had ten, three of whom died in childhood), for example. Often, they were sent across the Kentish fields with specific work orders: “Collect a hundred Lythrum plants and bring them home,” or “Track the routes of the bees that criss-cross the clover-studded meadows.”


Now a museum, Down House served as a rich source of evidence and inspiration for Charles Darwin.

Parslow the manservant helped, too, as did Darwin’s long-suffering wife, Emma, who watched with dismay as he carpeted the hallway of Down House with paper covered in frog spawn. Catherine Thorley, the children’s governess, assisted in the completion of a painstaking plant survey of nearby meadows. Schoolmaster Ebenezer Norman tabulated all of Darwin’s data for him. The local vicar helped build beehives.

Researchers also offered vital information. Kew Gardens botanist Joseph Hooker, for example, provided Darwin with fresh orchid specimens, sent express from London in sealed cans. (Despite ample evidence, Victorian scientists simply refused to believe that many plant species reproduce sexually. The idea that the orchids might be having sex in the parlor—in front of the children!—was simply too horrid to entertain. But it was so. And, with Hooker’s help, Darwin proved it.)

Costa has written about Charles Darwin and Alfred Russel Wallace—Darwin’s half-forgotten collaborator in evolutionary theory—before (1). But he has done something very important with this new book: He has brought Darwin fully to life.After all, Darwin’s face is familiar enough. There are many portraits of the famous naturalist: balding and white-bearded, with his benevolent eyes downcast. He even looks disapprovingly at us from a British 10-pound note as if to say, “Do you really need to buy that?”

But not until I read Costa’s book did I realize how completely these images fail to capture Darwin, the devoted father and industrious scientist. In Darwin’s Backyard, he strides across every page—collecting barnacles from the frigid water of the Firth of Forth, watching spiderlings float from the rigging of the Beagle, and investigating the cross-pollination of foxgloves in Wales.

Detailed do-it-yourself experiments can be found at the end of each chapter, allowing the reader to follow in the naturalist’s footsteps, reproducing, for example, his seed-salting studies of 1855 or his earlier work on barnacle morphology.

With Darwin’s Backyard, James Costa has written an intimate and big-hearted book. In its pages, readers will discover the real Darwin, a complicated man behind a revolutionary theory.


  1. J. T. Costa, Wallace, Darwin, and the Origin of Species (Harvard Univ. Press, Cambridge, 2014).

About the author

The reviewer is the author of The Lost Species: Great Expeditions in the Collections of Natural History Museums (University of Chicago Press, Chicago, 2017).