Sheep and goats are closely related animals that have been farmed together for centuries. Because they look and behave similarly, people often wonder whether they can be cross-bred.
Have you ever heard of an animal called a geep? It's the common name given to the offspring of a goat and a sheep. Reported in a few high-profile stories, the resulting youngster appears to exhibit characteristics of both parents – usually described as having the body of the sheep and the head of the goat, frequently with horns.
One relatively recent famous example of a geep was reported by Irish farmer Paddy Murphy from County Kildare in 2014. Speaking to the Irish Farmers Journal, Murphy said that he had witnessed a goat mating with his Cheviot ewes five months earlier but had dismissed the incident until the geep arrived on the scene, much to his surprise. Two years later, the Journal reported that the geep was doing well – resembling a Cheviot but black and with large curled horns.
Another goat-sheep hybrid born under natural conditions was observed in Botswana and reported in the US journal Veterinary Record, June 2000. In Botswana, goats and sheep are frequently kept together in a kraal (a fenced enclosure) and regularly observed mating. But, aside from this one occasion, no other offspring have been born alive. This particular geep lived to be at least five years old.
Despite the strength of these claims and others in France, Germany and New Zealand, some scientists are suspicious of most alleged geeps. Gary Anderson, Professor at University of California, Davis, has studied goat-sheep hybridisation and chimeras (where hybrids are created in a lab through genetic manipulation). Talking to Modern Farmer magazine, he says “there are very few legitimate documented cases” of naturally occurring geeps. He goes on to explain why.
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While it isn't unusual for goats and sheep to mate if they are kept together – they are both members of the Bovidae family, which includes cattle, buffalo and antelopes – it is extremely unusual for this to result in pregnancy. And if pregnancy does occur, the result is likely to be stillborn. This is because, despite superficial similarities in appearance, the species are from different genera (Genus Ovis for sheep, Capra for goats) and are genetically highly incompatible: sheep have only 54 chromosomes (distinct strings of DNA) compared to 60 in a goat.
A sheep-goat chimera is an animal created in a laboratory combining the embryos from sheep and goats. This was first carried out at the Institute of Animal Physiology in Cambridge in the early 1980s. The resulting animals are not so much a blend of goats and sheep but more a mosaic of the two species cells and tissues. For example, a chimera can have sheep's wool and goat hair intermingled. Most sheep-goat chimera appear to be fertile.
