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Darwin Correspondence Project

To ?   [before 25 May 1861]1

I am very much obliged to Mr Bennett for his information about Norwegian dun ponies;2 but I received some years ago, through the Consul-General, Mr Crowe, the same account, which probably came from Mr Bennett.3 The point on which I am anxious for information is, whether a cross between two coloured horses (neither of which are dun) ever produce duns. I believe that we could thus obtain some insight into the aboriginal colour of the horse. I have as yet only a single case of the parentage of a dun—namely, a bay horse and black mare. A German writer (Hofacker) on the breeding of horses gives the case of two chesnuts producing a “goldfalb”, which, I believe, is a dun; and of a chesnut and brown producing a mouse-dun (mausrapp).4 I hope “Eques” will fulfil his kind offer of giving more information on the subject.5 I have collected a considerable body of evidence on the remarkable tendency of the offspring of a cross between differently-coloured breeds reverting to the colour of the aboriginal parent.6 With pigeons, I made numerous crosses for this express purpose, and frequently got a near approach to the marks and colour of the wild rock-pigeon.7 Again, I crossed a Spanish cock and white silk-hen; and one of the cockerels, although at first coal-black, in the autumn assumed the splendid red plumage of the wild jungle-cock (Gallus bankiva). Two young Cocks from the black Spanish and white game-hen assumed red neck and saddle hackles, so as partly to resemble a pile game cock. Mr Brent crossed two varieties of duck, and some of the ducklings assumed the plumage of the wild duck.8 I could give other facts. For instance, it is asserted in work on poultry that hens raised from a cross between two breeds of fowls neither of which sit, are good sitters; and here we see a cross has brought back the proper aboriginal instinct of incubation. In my own experience, however, the crossed offspring from the Spanish cock and a Poland hen did not incubate. If anyone has any analogous facts to those above given, and would communicate them, I should be much obliged. The whole subject of the results of crossing distinct breeds is an interesting one under many points of view.—

Charles Darwin (Down, Bromley, Kent).


Dated by the publication of the letter in the 25 May 1861 issue of the Field. It appeared under the heading: ‘On dun horses, and on the effect of crossing differently coloured breeds’.
CD refers to a notice headed ‘Dun horses’ and signed ‘T. Bennett (Christiania)’ in the 18 May 1861 issue of the Field, p. 431. It was a response to CD’s letter to the Field, [before 27 April 1861]. Stating that ‘I was some time ago requested to get similar information’ on this subject (see n. 3, below), Bennett described the characteristics of the dun ponies of Norway.
The letter from John Rice Crowe, British consul-general in Norway, has not been found, but see Correspondence vol. 6, letter to Laurence Edmondston, 2 August [1857] and n. 5. CD included information on striping in the dun horses of Norway in Variation 1: 58, citing Bennett’s article in the Field as one of his sources (ibid., n. 31).
Hofacker 1828. There is an annotated copy of the work in the Darwin Library–CUL.
A response to CD’s letter to the Field, [before 27 April 1861], signed ‘Eques’ appeared in the 11 May 1861 issue of the Field, p. 404; the author used the term ‘mouse-dun’ to describe the coloration of colts bred from crossing a cream-coloured stallion and two yellow-dun mares. He promised to provide further information on the topic in a future number of the Field, which he did in the issue of 8 June 1861, pp. 493–4. There the writer corrected his earlier description of the colts, now calling them ‘golden-dun, nearly what Hofacker (as quoted by Mr Darwin) calls gold-falb’.
Many of CD’s notes on this topic are in DAR 205.7. For CD’s use of experiments in breeding domestic animals as a means of gaining information on the laws of variation, see Bartley 1992.
CD’s records of breeding experiments in which he crossed a number of different breeds of pigeon are in DAR 205.7: 166–89.
Bernard Philip Brent had provided CD with information about crossing a number of different domesticated birds. He is acknowledged on a number of occasions in Variation.


Is obliged to Mr Bennett for information, the same relayed through Consul General Mr Crowe.

CD is interested in information that provides insight into the colour of the aboriginal horse and the possibility that the offspring of a cross between differently-coloured breeds revert to the colour of the aboriginal parent. He has examined crosses between pigeons for this purpose and would welcome any analogous facts resulting from crossing of distinct breeds.

Letter details

Letter no.
Charles Robert Darwin
Sent from
Source of text
The Field, the Farm, the Garden, the Country Gentleman’s Newspaper 17 (1861): 451

Please cite as

Darwin Correspondence Project, “Letter no. 3156A,” accessed on 24 April 2019,

Also published in The Correspondence of Charles Darwin, vol. 9