Darwin & Zoology

Humans are animals. Many people most readily associate Darwin’s evolutionary ideas with other animals: monkeys, birds, whales etc. But neither Darwin’s theoretical work nor his practical studies were limited to any one group. Darwin worked on all the major divisions of the study of life: botany, paleobiology and zoology. Before he published his ideas on evolution he was an established zoologist (and geologist) and Darwin’s final research project was on an animal.

The Collector

Darwin was born a naturalist; large chunks of his youth were spent rummaging through his father’s gardens and land looking for interesting critters. Darwin himself even reflects on his early habits in his Autobiography; he writes that the ‘passion for collecting, which leads a man to be a systematic naturalist, a virtuoso or a miser, was very strong in me, and was clearly innate’. As he grew a little older, his intentions whilst searching out the wildlife of his father’s land changed slightly and he became an avid shooter. Shooting birds was then a very acceptable sport which the young Darwin clearly enjoyed and was very good at. But his passion for shooting eventually faded. One story states that he once came across a bird that was shot the day before but was still alive; another tells of a beetle that was sent to him as an old man, alive but clearly suffering, Darwin gently put both of these creatures out of their suffering. It is also clear that Darwin’s zeal for shooting on the Beagle voyage started to diminish, and he often hired men to do the shooting for him.

His passion for collecting never stalled. As a university student at Christ’s College, Cambridge Darwin was an avid beetle collector, eventually amassing one of the best beetle collections he knew of. His beetle collecting also got his name in print for the first time. J. F. Stephen lists Darwin as a collector in his Illustrations of British Entomology. Throughout his life Darwin continued to collect. On the Beagle voyage it was his main occupation, and he later collected (by post)enough barnacles to write the authoritative account of the group. His next project saw him collect the bones and measurements of many domestic animals. Not forgetting the greatest hallmark of Darwin’s work - his collection of facts which he used so well to outline and support his theories!

The Zoology of the Beagle

Darwin, like many young Victorians, started his scientific career with a voyage around the world. The job of these young scientists was to collect and describe specimens from across the globe which had never been seen by Europeans. Darwin did his fare share of cataloguing and describing species, he made 368 pages of notes on zoology, and his catalogues listed 1529 species in spirits and 3907 labelled skins, bones and other dried specimens. That’s more than 3 specimens a day, every day, for 5 years - not bad considering a lot of his time was spent travelling! He even brought a baby Galapagos tortoise back with him alive, it grew two inches on the journey home.

When he returned home, thanks to Henslow who published his findings and published extracts of Darwin’s letters home, and a £1,000 grant from the Chancellor of the Exchequer himself, Darwin was able to work with renowned experts of the day to write up his notes for the scientific community. The result was the 5-volume Zoology of the Voyage of the H.M.S. Beagle. There was a volume on Darwin’s fossil mammal specimens, written by Richard Owen, professor of anatomy and founder of the London Natural History Museum. The curator of the Zoological Society, George Waterhouse wrote a chapter on living mammals. John Gould, the most famous ornithologist of the Victorian era, classified and described Darwin’s bird collection; he was the first to conclude that ‘Darwin’s Finches’ were 13 species not one – a famous moment in the history of biology! Darwin’s naturalist friend Leonard Jenyns described Darwin’s fish with the help of Darwin’s descriptions of their colour patterns (which faded in the preserving spirits). And the reptiles and amphibians were described by the dentist-turned-naturalist Thomas Bell.

The five volumes were lavishly illustrated with expensive engravings of the animals described. These engravings now illustrate this website too!


Darwin was to spend eight hard years on barnacles, toiling away dissecting these tiny creatures under the microscope. The result was a four volume monograph on the Cirrepedia, living and extinct – the authoritative text on barnacles then and probably still now. The barnacle years pushed him to his limits, his health almost bottomed out, he lost his father and mentor and then, crushingly, his favourite child Annie.

The result of his work, a 4-volume definitive account of barnacles cemented his place in science. Despite its dry tone and specialist nature, it received rave reviews in the scientific press. He was rewarded with many accolades, memberships to yet more societies and even the Royal Medal, one of the highest awards in British science. Read more…

Variation and Pigeons

For evolution by natural selection to occur individuals of a species must be variable. Slight differences in size, colour, behaviour, physiology and all the other components of living things must exist. Furthermore these variations must be evolutionarily meaningful; that means two things:

  • they have to have some effect on survival and reproductive success
  • these differences must be heritable; they have to be passed on from parent to offspring

The existence of variation may not seem like a major problem now; scientists have become very used to thinking about species in a way known as ‘population thinking’. Population thinking emphasizes the uniqueness of each individual within a population. Darwin’s strategy to persuade his readers of this new way of thinking, and the scope for natural selection to act, had from quite early on been by analogy with artificial selection. Darwin’s most complete example of this analogy was his study of fancy pigeons! Read more…


Darwin’s most famous work was on evolution. His theories of natural and sexual selection now underpin all biology. To demonstrate the principles of his ideas and to support them with what evidence was available, Darwin turned to his extensive knowledge of zoology, botany and geology. On The Origin of Species, The Descent of Man and his other theoretical books illustrate the breadth and depth of Darwin’s understanding of the natural world. He is able to draw on such different biological fields as embryology and the fossil record, variation in pigeons and the novelties of the platypus, the dimensions of bones and the different ways we and other animals express emotions. Such a wide ranging set of interests and such detailed knowledge of many topics allowed Darwin, uniquely, to integrate different sources of information, to tie the biological world with the environment, to formulate his evolutionary theories, and then of course to support them with evidence! Read more….


Darwin died in the spring of 1882. His last major published work was on the earthworm: The Formation of Vegetable Mould, Through the Action of Worms went on sale in 1881. Somewhat surprisingly it was a big hit, initially selling more copies than The Origin had. For Darwin this last work was a return to his early interests, invertebrates were his first major passion. He studied sponges under Robert Grant in Edinburgh and feverishly collected beetles in Cambridge. He kept his interest in invertebrates throughout his life and by 1881 had been studying worms for years.

Darwin’s work on worms during his latter years also reflected his interest in processes that, acting through a slow, gradual process, over time have a huge impact. The habits of earthworms do just this. As Darwin wrote ‘worms have played a more important part in the history of the world than most persons would at first suppose’. Read more…

Written by Stephen Montgomery

References & Further Reading

The Autobiography of Charles Darwin
by Charles Darwin (Edited by Francis Darwin), The Thinker's Library: 1929

by John van Wyhe, Andre Deutsch: 2009

by Adrian Desmond & James Moore, Penguin: 1991

Journal of Researches
by Charles Darwin, 1839 (any edition)

On the Origin of Species
by Charles Darwin, 1859 (any reprint - 2nd edition preferable)

See also further reading in the next few articles.