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Darwin Correspondence Project

From Robert Swinhoe   2 December 1862

18 Royal Avenue Terrace | Chelsea. SW.

2 Decr. 1862.

My dear Sir,

I have just turned out another domestic animal which I had laid aside for you—a Guinea Pig.1 It is of the Chinese breed, and may perhaps be interesting to you for comparison with the European bred animals. I heard it asserted the other day at Cambridge that the domestic Guinea-pig would not interbreed with the Rock Cavy, it’s supposed parent-stock, and that consequently a new species had been formed by artificial selection. Have you heard of this asserted fact?2 The person that gave it forth at Cambridge had it I believe on good authority. I should like much to hear your opinion on this subject.

I remain, | Dear Sir, | Your’s very truly,

Robert Swinhoe

Charles Darwin, Esqre.


Swinhoe, who had previously supplied CD with animal specimens, had recently returned from the Far East, bringing with him a large natural history collection (see letter from Robert Swinhoe, 12 November 1862).
No letter to Swinhoe on this point has been found.


Sends CD a Chinese breed of guinea-pig. Has heard it claimed that the domestic guinea-pig will not interbreed with the wild rock cavy and that, therefore, artificial selection has formed a new species.

Letter details

Letter no.
Robert Swinhoe
Charles Robert Darwin
Sent from
Source of text
DAR 177: 327
Physical description
ALS 3pp

Please cite as

Darwin Correspondence Project, “Letter no. 3842,” accessed on 23 May 2022,

Also published in The Correspondence of Charles Darwin, vol. 10