Otter-sheep Hybrids?

Ancon sheep

Note: It has been my policy in listing reports of mammalian hybrids to include all serious allegations by serious individuals, especially scholars, whether or not the hybrid alleged seems possible or likely to me. This policy, I think, helps to eliminate subjective judgment on my part, and therefore should eliminate at least one source of systematic bias from my work.

Note: This extremely disparate cross has been alleged in old reports, but the actual occurrence of otter-sheep hybrids has never been established.

The Ancon breed of sheep (see photo right) differs markedly from ordinary sheep. These sheep have long bodies, extremely short legs and crooked forelegs. They also carry their heads down, in line with the spine, instead of up like normal sheep, a condition known as “down head.” Substantially smaller than ordinary sheep, they were originally known as the Otter breed because it was thought at the time the first such sheep was born that it had been produced by a mating between an otter and a ewe. Thus, a paper published in the Philosophical Transactions of the Royal Society (Humphreys 1813) and describing the new breed of sheep mentions the possibility that the founding individual might have been derived from such a cross. The relevant passage in the article (Humphreys 1813, p. 88), reads as follows: “Seth Wight, who possessed a small farm on the banks of Charles River, in the town of Dover and State of Massachusetts, about sixteen miles distant from Boston, kept a little flock

At the time, belief in hybrids between very disparate sorts of animals, even ones between humans and non-human animals, was far more prevalent than it is today. For example, many early nineteenth century veterinarians believed that a horse could cross with a cow. In 1826, a physician published a detailed description of what he thought was a cow-human hybrid. Most modern biologists would, however, scoff at such a notion, and the Ancon breed is now generally believed to have had its origin in a mutation (Gidney 2007).

Skeleton of an otter

Whether such sheep come into being by mutation or via rare, strange hybridization events, it is known that they have done so more than once. The line descended from the single lamb yeaned on Seth Wight's farm in 1791 was maintained for some time, due to its desirable inability to jump fences, but was eventually allowed to die out because their wool was not as fine as that of Merinos. However, such sheep continued to appear as individuals in flocks (Gidney 2007; Shelton 1968). Late in the nineteenth century, in a letter to the editor of the National Livestock Journal (Anonymous 1882) a subscriber stated that otter sheep were still being yeaned occasionally in flocks by normal sheep at that time: “In your April number is an inquiry, why many the lambs of the Humphrey, or Atwood sheep have

This recurrence of the otter traits in individuals yeaned in flocks that were otherwise normal suggests that a rare recessive gene (or set of genes), when homozygous, causes the Ancon traits to occur. However, what seems to be the only study to argue that these animals are the result of a mutation (Chang 1949) offers no genetic evidence, so the basis of this phenotype remains an open question.

It's of interest that a 16th century archaeological site in Leicester, UK, recently produced bones of an apparent Ancon individual predating by about 200 years Seth Wight's sheep, which had been the earliest such an animal known (Gidney 2007).

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By the same author: Handbook of Avian Hybrids of the World, Oxford University Press (2006).

Note. In the Origin of Species Darwin argued that new forms of life typically arise gradually from preexisting forms, but he did mention the Ancon sheep as a rare case of a new breed arising abruptly.

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