From J. E. Gray 2 April 1871
2.4.71
My dear Darwin
The two toed sloth and the black crested the toed Sloth Brady torquatus are Both Sexes alike But the females Ai (Arctopithecus Gray) are covered with uniform fur varing in length and colour in the different Species The Male have a path of short shining very soft hair between shoulders1 In three out of the four species in the B.M this patch is large and of a bright orange yellow color with a central black streak and black spots on the edge2 In the other (A flaccidus) the patch is small and pure white with a short black central streak3
The female of A. griseus4 has a small pure white tuft of very soft hair like a powder puff on each side of the back over the loins almos hid from view by the longer hairs of the fur I have not found these tuft in the females of the other species Buffon who knew the male of one species called the Ai a dos brulee which Lesson has named Acheus ustus.5 Teminck thought the spot was produced by the long hair being worn off6
Wagler in 1813 suggested they were the males and lately I have been able to verify the fact7
With kindest regards | Ever yours sincerely | J E Gray
I did not learn to write with my left hand until I was more than 70 so excuse its badness8
Footnotes
Bibliography
Buffon, George Louis Leclerc, comte de, et al. 1749–1804. Histoire naturelle, générale et particulière, avec la description du cabinet du roy. 44 vols. Paris: Imprimerie royale.
Descent 2d ed.: The descent of man, and selection in relation to sex. By Charles Darwin. 2d edition. London: John Murray. 1874.
Lesson, René Primevère. 1840. Species des mammifères bimanes et quadrumanes; suivi d’un mémoire sur les oryctéropes. Paris and London: J.-B. Baillière.
ODNB: Oxford dictionary of national biography: from the earliest times to the year 2000. (Revised edition.) Edited by H. C. G. Matthew and Brian Harrison. 60 vols. and index. Oxford: Oxford University Press. 2004.
Temminck, Coenraad Jacob. 1820. Sur le genre Bradype et description d’une espèce encore peu connue. Annales générales des sciences physiques 6: 204–18.
Wagler, Johann Georg. 1831. Mittheilungen über die Gattungen der Sippe Bradypus. Isis (1831): 604–12.
Summary
Sexual differences in sloths. J. G. Wagler article on sloths [Isis 24 (1831): 604–12].
Letter details
- Letter no.
- DCP-LETT-7652
- From
- John Edward Gray
- To
- Charles Robert Darwin
- Sent from
- unstated
- Source of text
- DAR 88: 95–6
- Physical description
- ALS 3pp
Please cite as
Darwin Correspondence Project, “Letter no. 7652,” accessed on 6 October 2024, https://www.darwinproject.ac.uk/letter/?docId=letters/DCP-LETT-7652.xml
Also published in The Correspondence of Charles Darwin, vol. 19