Ewart's Penycuik experiments: Lord Morton's case repeated with a zebra
Experiments repeating Lord Morton's case, with a Burchell's zebra in place of the extinct quagga. Mares of various breeds were put to a zebra stallion, striped hybrids were obtained, and the same mares were then mated with stallions of their own breed; other mares that had never seen a zebra served as controls.
The experiments were made in the 1890s at Penycuik by the Scotsman James Ewart, professor of natural history. By his later count, thirty mares produced seventeen hybrids and twenty pure-bred foals; faint stripes on three of them disappeared with the foal coat, and the same stripes turned up on control foals. No trace of 'infection' was found in coat, mane, hoofs or temper, and the same held for dogs and other animals.
Ewart did exactly what, in his words, Weismann had called for: he turned the breeders' tradition into a methodical experiment, and the tradition did not survive it.
Why this date
The date follows the first publication of the results: J. C. Ewart, 'The Penycuik Experiments', London: A. and C. Black, 1899 (imprint checked against the Internet Archive catalogue). The crosses were begun about 1894-1895 on Ewart's private farm near Edinburgh; parts of the book had appeared earlier in The Veterinarian (1895, 1897-1898) and The Zoologist (1898). The lower bound of the label follows the University of Edinburgh's dating.
Other links
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Telegony: Lord Morton's mare and the 'infection' of the dam by her first mate
refuted by · Confidence: medium
Ewart repeated Morton's case with a zebra in place of the quagga, with control mares and several breeds, and found no trace of the zebra in any later foal; the same held for dogs and other animals. He concluded himself that 'the telegony tradition is not confirmed' by methodical experiment.
Dispute: The confidence is medium for two reasons. First, the strongest testimony is Ewart's own (the 1911 article), and the secondary sources are University of Edinburgh pages rather than a historian's work; the key historical paper, Burkhardt's 'Closing the Door on Lord Morton's Mare: The Rise and Fall of Telegony' (Studies in History of Biology 3, 1979, 1-21), is not available online and was not read. Second, the refutation was not instantaneous. In the 1899 book Ewart is still cautious and writes conditionally of 'should the fact of telegony be proved'; the unqualified conclusion appears by 1911, and the doctrine finally faded after 1900 together with the Mendelian explanation, under which stripes in Arab horses are reversion to ancestors, not a memory of the quagga. Separately: in 2014 Crean and colleagues described in the fly Telostylinus angusticollis an effect of the first male on offspring size through seminal fluid, which is called 'telegony' in a new sense; it has no bearing on the inheritance of the quagga's characters.
Link sources
- James Cossar Ewart (1851-1933), Our History, University of Edinburgh (2014) Verified 20 Sep 2026
To do this, Ewart repeated a classic experiment which supposedly proved this theory, the case involving the Arab mare belonging to Lord Morton which produced a striped foal after mating with a quagga, even when subsequently served by an Arab stallion. Ewart's experiment used a Burchell's zebra (the quagga having become extinct), but found that the 'subsequent foals' showed no signs of having been affected by a previous zebra sire. The results of his work were published in The Penycuik Experiments (1899).
- J. C. Ewart, «Telegony», Encyclopaedia Britannica, 11th ed., vol. 26 (1911) Verified 20 Sep 2026
Similar results having been obtained with horses and asses, there is no escape from the conclusion that the telegony tradition is not confirmed by such methodical investigations as were suggested some years ago by Professor Weismann (see Cossar Ewart, The Penycuik Experiments, 1899).
- Zebra Crossing: James Cossar Ewart, Romulus and the Penicuik Experiments, Towards Dolly (2013) Verified 20 Sep 2026
His most famous experiments were related to telegony, which is the theory, accepted at the time by most scientists and breeders, that ‘a previous sire may so “infect” the dam served by him as to impress certain of his characters upon her subsequent offspring by other sires.’ Ewart’s experiments with a variety of species; however, were uniformly negative.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.
- James Cossar Ewart (1851-1933), Our History, University of Edinburgh (2014) Verified 20 Sep 2026
Node sources
- J. C. Ewart, The Penycuik Experiments, London: A. and C. Black, 1899 (1899) Verified 5 Oct 2026
I HAVE been frequently asked when an account is likely to be published of the telegony and other experiments I started some time ago at Penycuik.
- J. C. Ewart, «Telegony», Encyclopaedia Britannica, 11th ed., vol. 26 (1911) Verified 5 Oct 2026
The quagga having become extinct, a number of mares were put to a richly striped Burchell zebra, and subsequently bred with Arab, thoroughbred and cross-bred sires. Other mares were used for control experiments. Thirty mares put to a Burchell zebra produced seventeen hybrids, and subsequently twenty pure-bred foals. The mares used for control experiments produced ten purebred foals.
- James Cossar Ewart (1851-1933), Our History, University of Edinburgh (2014) Verified 5 Oct 2026
In around 1894, Ewart began his investigations into experimental breeding, the work for which he was to become best known. He was especially concerned with disproving the long-held theory of Telegony, which held that a sire may 'infect' the dam he serves so as to influence the characteristics of future offsprings from different sires.
- Clare Button, James Cossar Ewart and the Origins of the Animal Breeding Research Department in Edinburgh, 1895-1920, Journal of the History of Biology 51 (3), 445-477 (2018) Verified 5 Oct 2026
Although presently a marginal figure in genetics historiography, Ewart established two sites for experimental animal breeding work between 1895 and 1911 and played a central role in the founding of Britain’s first genetics lectureship, also in 1911.
"Verified" means that on that day the quotation was found at the address given, word for word. No date means we have not been able to open the source yet, not that the quotation is wrong.