Ɛpsilon

To the Field   [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).

1
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’.
2
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.
3
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).
4
Hofacker 1828. There is an annotated copy of the work in the Darwin Library–CUL.
5
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’.
6
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.
7
CD’s records of breeding experiments in which he crossed a number of different breeds of pigeon are in DAR 205.7: 166–89.
8
Bernard Peirce Brent had provided CD with information about crossing a number of different domesticated birds. He is acknowledged on a number of occasions in Variation.

Please cite as “DCP-LETT-3156A,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-3156A