Q From Steve Lawson, York: I told someone recently that they were being used as a guinea pig, which puzzled them. I explained the meaning but was at a loss to explain its origins. The obvious reason is that the creatures were used in experiments but this seems odd: why would scientists use a creature that would cost a lot to import when rats and mice would have been free?
A There are many puzzles about this inoffensive little animal, not least that it isn’t a pig and it doesn’t come from Guinea. It’s actually a rodent from central South America, though the variety that children have as pets doesn’t occur in the wild.
Why it should have that name is a mystery; the Oxford English Dictionary hazards a guess that it might have been confused with the Guinea hog, a hardy species of pig which did come from the Guinea coast of Africa, was taken to the US as part of the slave trade, and was at one time a common homestead pig in rural America. The problem with this, as the OED’s editors surely knew, is that guinea pig is actually about a century older as a term in English than guinea hog, which is known from 1664. The guinea pig was early on also called the Spanish coney (coney being the old name for a rabbit, which was applied by sailors and explorers to any small, furry, vaguely rabbit-like animal they encountered; Spanish because it came from the Spanish colonies in South America); it has been suggested that coney became corrupted to guinea. Yet a third story suggests that it was first brought to Britain in Guineamen, vessels that did the triangular voyage to Guinea and the New World as part of the slave trade, but similar problems about dating crop up here. Either way, it seems to have ended up being called a pig because it does squeal a bit like one. The animal became quite widely known in Europe and America from the eighteenth century on.
I’ve gone into all that partly because people often ask me, but also as a consolation prize because I can’t answer your question. I just don’t know, nor does anyone that I’ve asked. The guinea pig was certainly used for medical experimentation in the nineteenth century — there are many examples mentioned in the literature going back at least as far as the 1850s. Its advantages may have been those that also recommended it as a pet — it doesn’t bite much, it’s not a fussy eater, and it’s long-lived. Very usefully, in some respects the guinea pig is rather like us, for example in its immune reactions and its need for vitamin C in its diet. In the early 1880s, the German scientist Robert Koch used guinea pigs, which suffer from tuberculosis in the same way as humans, to determine what caused the disease. In Paris, Louis Pasteur used the animals for his work on rabies in the 1880s and 1890s.
The first known use of guinea pig to refer to a human who was being experimented upon is by George Bernard Shaw in 1913. But it has proved impossible to make any direct link to experiments that used the animals or why that particular experimental subject should have so caught the imagination that it should have been taken up as a metaphor (except that guinea pig sounds more exotic than lab rat). My suspicion — and I can hardly rate it any higher — is that it was the famous experiments of Robert Koch and Louis Pasteur that brought guinea pigs to wide general attention as experimental animals. Beyond that it’s impossible to go.