In the Narrative of [the sailor] William Spaven it is mentioned that lads, who pay for their entrance into the service of the East India Co. are called Guinea Pigs. An obvious synonym for g.p. would be "test animal", since etymological explanations are all zoological. However, I am not sure whether guinea pigs were used in an experimental context already in the 18th century.

  • In Norway the animal is called "marsvin" - "mar-swines"... supposedly from German "Meerschweinchen", meaning "little sea-pigs". On a side-note, "marsvin" just refers to the animal - it doesn't also have the meaning "test-subject" in Norwegian. Interesting with the sea-connection... Perhaps the Germans also used "Meerschweinchen" for new ship-recruits? Commented Mar 18, 2017 at 10:14

2 Answers 2


Neither "test subject" nor "Guinea coin" are the origin (unless time travel).

One instance, considered to be the earliest, was published in 1653:

For in a woman it groweth to the bottom of the womb, and is distant a great way, that is by the length of long vessels from the foetus: but in Mice, Ginny-pigs, and Conies, it is annexed partly to the Region of the Loynes, partly to the sides of the breast.

For comparison, the Guinea coin was first minted in 1663. That's ten years later!

The first use of guinea pig to mean "test subject" was 1913 (according to OED). That's... many years later! It's also later than the meaning you see in the Narrative of William Spaven.

The etymology according to Etymonline:

Perhaps so called either because it was brought back to Britain aboard Guinea-men, ships that plied the triangle trade between England, Guinea, and South America [Barnhart, Klein], or from its resemblance to the young of the Guinea-hog "river pig" [OED], or from confusion of Guinea with the South American region of Guyana (but OED is against this). Pig probably for its grunting noises.

It also indicates that guinea pigs were commonly used for medical experiments by 1865.


I'd suggest a connection between the would-be seamen being called Guinea Pigs and the fact that payments for them were calculated in Guineas.

  • 1
    Interesting theory about the guinea, but what about the pig? I'm paid in pounds but not, as far as I know, called a pound pig.,
    – davidlol
    Commented Mar 18, 2017 at 10:39
  • The 'pig' part is not significant. Before the use of cavies as laboratory animals in modern science, the term 'guinea pig' as a metaphor suggested an association with money. Commented Mar 18, 2017 at 10:51
  • I am not sure myself, since the etymological explanation, namely the reference to domestic animals which are raised by cultures in the East (guinea for far away country) for their diet (similar to rabbits) holds somehow. My question came up in connection with an adequate translation in the above context in which a monetary reference makes more sense.
    – xaron
    Commented Mar 18, 2017 at 11:37
  • 1
    Hello, xaron. To quote tchrist, [On ELU,] we are looking for more substantial answers with documented references, not merely [statements that may possibly be no more than] personal opinion [and especially conjecture]. Those are just comments, not answers. // If you haven't enough reputation to add a comment here yet, please realise that we've all been in that situatuation. Commented Mar 18, 2017 at 13:01

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