Darwin’s Early Love

Charles Darwin, the famous naturalist known around the world for his publication On the Origin of Species and contributions to evolutionary theory, was born on February 12, 1809. As such, February 12 is known as International Darwin Day – a celebration with a vision to:

“Inspire people throughout the globe to reflect and act on the principles of intellectual bravery, perpetual curiosity, scientific thinking, and hunger for truth as embodied in Charles Darwin. It will be a day of celebration, activism, and international cooperation for the advancement of science, education, and human well-being.”

February 12 also happens to be just days before Valentine’s Day, a holiday now associated with love and the presentation of valentines as expressions of affection. How might these two, seemingly disparate holidays, be brought together? Why not by thinking about who Darwin himself might give a valentine to in the natural world?

Many people, when thinking of Darwin, might associate him with finches, mockingbirds, rheas, or Galápagos tortoises. But when Darwin began to investigate natural history while studying medicine in Edinburgh in the 1820s, it was marine invertebrates that first sparked his interest. While still a teenager, Darwin became a member of the Plinian Society, which was dedicated to the study of natural history amongst Edinburgh students. The zoologist Robert Edmond Grant nurtured Darwin’s interest in natural history, especially marine invertebrates, and taught him how to collect and rear specimens. Darwin’s first scientific paper, which was presented to the Plinian Society in March of 1827, was about bryozoan larvae and the black spots sometimes seen on oyster shells, which he demonstrated were the eggs of marine leeches. Sadly, Darwin’s mentor Grant had presented these same findings just days before Darwin at another venue, leading Darwin to feel betrayed and prompting his exodus from Edinburgh (Stiassny, 83).

Time passed, Darwin spent some time at Cambridge, and eventually he joined the voyage of the HMS Beagle thanks to a recommendation from his new mentor, botanist and geologist John Stevens Henslow. Darwin’s observations and research during the voyage would fuel his later revolutionary theories. But, as Dr. Melanie L.J. Stiassny, a curator at the American Museum of Natural History, points out in her article on Darwin within the book Natural Histories: Opulent Oceans, Darwin felt somewhat hesitant about his ideas during the early stages of their development. After all, they represented an entirely new way of looking at the natural world and thinking about its origins. So, while he fleshed out his theories on natural selection, Darwin also turned his attention back to, as Stiassny calls it, “his early love” – marine invertebrates. It was his work on barnacles that arguably helped pave the way for the acceptance of his later theories. As Stiassny states on page 84 of Opulent Oceans:

“It was the study of one group, the barnacles (Cirripedia), that would solidify his credentials as a taxonomic expert and provide him with empirical evidence for many of his evolutionary ideas…such as the loss of unnecessary structures (barnacles have no trace of the abdominal segments and swimming appendages of other crustaceans), and evidence that features inherited from a common ancestor can transform in anatomy and function (the typical walking limbs of crustaceans are modified into specialized feeding cirri in barnacles).”


Darwin spent eight years working on his barnacle studies, and from 1851-54 finally published his work in a four-part series: A monograph on the sub-class Cirripedia, with figures of all the species. Within the work, Darwin provides a classification for the crustacean Subclass Cirripedia, making it “the first based on the evolutionary principle of common descent” (Stiassny, 85). His On the Origin of Species, published in 1859, five years after his Cirripedia work, references cirripedes twenty-six times, demonstrating the impact this research had on Darwin’s evolutionary ideas.

Darwin’s name is arguably the most well-known from the world of natural history. Knowing Darwin’s history with the Cirripedia, one might wonder if he would have realized the heights of his scientific achievements without his barnacles.

So, we think, if Darwin were to give a Valentine to someone in the non-human animal kingdom, there’s a good chance it would go to a barnacle.


Stiassny, Melanie L.J. (2014). Darwin’s “Beloved Barnacles.” Natural Histories Opulent Oceans: Extraordinary Rare Book Selections from the American Museum of Natural History Library (pp. 82-85). New York: Sterling Publishing.

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Grace Costantino served as the Outreach and Communication Manager for the Biodiversity Heritage Library from 2014 to 2021. In this capacity, she developed and managed BHL's communication strategy, oversaw social media initiatives, and engaged with the public to excite audiences about the wealth of biodiversity heritage available in BHL. Prior to her role as Outreach and Communication Manager, Grace served as the Digital Collections Librarian for Smithsonian Libraries and as the Program Manager for BHL.