Well before Darwin, some were thinking about human origins, and the search for mermaids to demonstrate our aquatic roots was part of the story:
On May 6, 1736, the polymath Benjamin Franklin informed readers of his Pennsylvania Gazette of a “Sea Monster” recently spotted in Bermuda, “the upper part of whose Body was in the Shape and about the Bigness of a Boy of 12 Years old, with long black Hair; the lower Part resembled a Fish”. Apparently, the creature’s “human Likeness” inspired his captors to let it live. A 1769 issue of the Providence Gazette similarly reported that crew members of an English ship off the coast of Brest, France, watched as “a sea monster, like a man” circled their ship, at one point viewing “for some time the figure that was in our prow, which represented a beautiful woman”. The captain, the pilot and “the whole crew, consisting of two and thirty men” verified this tale.1
The above examples are quite representative of what an early modern Briton would have found in the newspapers. That these interactions were even reported tells us much. Intelligent men like Benjamin Franklin considered such encounters legitimate enough to spend the time and money to print in their widely read newspapers. By doing so, printers and authors helped sustain a narrative of curiosity surrounding these wondrous creatures. As a Londoner sat down with his paper (perhaps in the aptly named Mermaid Tavern) and read of yet another instance of a mermaid or triton sighting, his doubt might have transformed into curiosity.2
Philosophers’ debates over mermaids and tritons in this period reveal their willingness to embrace wonder in their larger quest to understand the origins of humankind. Naturalists used a wide range of methodologies to critically study these odd hybrids and, in turn, assert the reality of merpeople as evidence of humanity’s aquatic roots. As with other creatures they encountered in their global travels, European philosophers utilized various theories — including those of racial, biological, taxonomical, and geographic difference — to understand merpeople’s and, by proxy, humans’ place in the natural world.3Vaughn Scribner, “Mermaids and Tritons in the Age of Reason” at Public Domain Review (September 29, 2021)
So when Darwin came along and said, no, apes, he was playing to a sympathetic audience.