skip to content

Darwin Correspondence Project

From Arthur Russell   15 April 1872

10, South Audley Street. W.

April 15 | 1872

Dear Mr. Darwin

Some years ago I imported from France a lot of Ranæ esculentæ and put them into a pond at Woburn Abbey, where they have done very well & increased in numbers, and where their croaking charms me every summer.1 I observed that some of the females were compelled to submit in the spring to the rude embraces of common English toads2 & I expected that the discovery of a new species of batrachian in Bedfordshire would be announced some day. Being at Woburn during the Easter holidays I observed a French frog who had copulated with a female toad— I took them home & kept them till the toad had spawned. I brought the spawn with me but though it has not yet decayed it does not seem to develop. I want to ask you whether you know of any experiments in crossing frogs & toads or R. esculenta with R. temporaria, our common frog? I think I remember reading that Spallanzani tried these experiments long ago without success.3

Excuse the liberty I have taken and believe me | yrs. sincerely | Arthur Russell

CD annotations

Top of letter: ‘Hybrids’ pencil


Rana esculenta is the edible frog, which it is now considered to be a hybrid of Pelophylax ridibundus (the Eurasian marsh frog) and P. lessonae (the pool frog). Although fertile, the hybrid (now known as P. esculentus or P. kl. esculentus) will normally only persist when it mates with one or other of its parent species in mixed populations, but viable hybrid-only populations have been identified (see Christiansen and Reyer 2009, pp. 1756–7, for more on reproduction in the edible frog). For more on Russell’s interest in natural history at the family seat at Woburn Abbey in Bedfordshire, see Correspondence vol. 17, Appendix V.
The common toad is Bufo bufo.
For more on Lazzaro Spallanzani’s unsuccessful attempts in hybridising frogs and toads, see Capanna 1999, pp. 191–2.


Capanna, Ernesto. 1999. Lazzaro Spallanzani: at the roots of modern biology. Journal of Experimental Zoology: Part B, Molecular and Developmental Evolution 285: 178–96.

Correspondence: The correspondence of Charles Darwin. Edited by Frederick Burkhardt et al. 27 vols to date. Cambridge: Cambridge University Press. 1985–.


Has acquired some French frogs, Rana esculenta, which have mated with R. temporaria, but the spawn has not developed.

Asks whether anyone has successfully crossed frogs and toads.

Letter details

Letter no.
Arthur John Edward (Arthur) Russell, Lord Arthur Russell
Charles Robert Darwin
Sent from
London, South Audley St, 10
Source of text
DAR 176: 225
Physical description
4pp †

Please cite as

Darwin Correspondence Project, “Letter no. 8286,” accessed on 4 April 2020,

Also published in The Correspondence of Charles Darwin, vol. 20