To George Cupples   [6–9? January 1869]1

For example, and before I in the least knew what the result would be, I fixed on this as a crucial instance,—the reindeer alone (of cervidæ) has horns in both sexes, therefore, according to my rule, their horns should be developed very early in life;2 and I now hear from Sweden that these appear within two or three weeks after birth:3 whilst with all other deer, in which the horns are confined to the male, these do not, as far I have hitherto ascertained, appear till nearly a year after birth. So it is with the horns of antelopes. Now you will see that if a large part of the variation in stature occurs late in life among male deer-hounds, this variation will (on such a principle) tend to be transmitted to the males alone, and will not affect the females as any other ordinary variation would do.4

The date is conjectured from the relationship between this letter and the letters from George Cupples, 4 January 1869, 11 January 1869, and 21 January 1869, and the letter to Sven Nilsson, 5 January 1869. The responses contained in Cupples’s letter of 21 January 1869 indicate that he had passed on CD’s query about the first appearance of horns in the sexes of different species of deer.
The reindeer is Rangifer tarandus (family Cervidae). For CD’s theory of the emergence of characteristics at different developmental stages, see Descent 2: 244.
CD had received the information from Sven Nilsson (see letter to Sven Nilsson, 5 January 1869 and n. 1).
In Descent 2: 261–2, CD cited Cupples for information on the development of deer-hounds.

Please cite as “DCP-LETT-6546F,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-6546F