Ɛpsilon

From Lawson Tait   16 March [1875]1

7, Great Charles St. | Birmingham.

March 16

Dear Sir,

Thanks for your kind note. I shall send you a copy of my little paper.2

I am keeping a number of white mice to try to unravel the use of the peculiar tail of mice & rats but I am completely beaten3

My view does not preclude any other modification or use of the tail: but it seems to me to be important as illustrating how correlation of growth (that is thick fur leading to a bushy tail) will bring out a new circumstance favourable to survival & truly lead to a total alteration of some important habits—as the curling up of these animals when going to sleep4

Yours faithfully, | Lawson Tait

PS. I had missed the Yak in my search for animals with a bushy tail.5 But he has a long abdominal fringe of hair nearly touching the ground. When he lies down with his limbs drawn up to or under him, as all ruminants do, his tail & fringe would act as a railway rug, preventing loss of heat from the limbs & damage to them from frost bite—as the tissue outside the bone is thin & there is nothing but a rather weak circulation to resist loss of heat. He lives close to the line of perpetual snow—the very condition under which such an epithelial appendage would conduce to survival

L.T.

1
The year is established by the relationship between this letter and the letter from Lawson Tait, 12 March [1875].
2
No copy of the paper Tait delivered at the Birmingham Natural History Society has been found in the Darwin Archive–CUL, but a summary was published in the Birmingham Daily Post, 8 April 1875, p. 5, and later reprinted in Hardwicke’s Science-Gossip in June 1875 (Tait 1875a); it included CD’s remarks from his letter to Tait of [13–15 March 1875].
3
Tait wanted to determine the use of tails in different animals (see letter from Lawson Tait, 12 March [1875]). In the published summary, Tait concluded that he had yet to find a reasonable explanation for the tails of rats and mice (Tait 1875a, p. 127).
4
In his letter to CD of 12 March [1875], Tait hypothesised that the bushy tails of some animals helped to retain heat when the animal was curled up.
5
In his letter to Tait of [13–15 March 1875], CD had mentioned the hairy tail of the yak, wondering whether it served any purpose other than as a fly-flapper.

Please cite as “DCP-LETT-9889,” in Ɛpsilon: The Charles Darwin Collection accessed on 5 June 2025, https://epsilon.ac.uk/view/dcp-data/letters/DCP-LETT-9889