HYBRID SWINE

HYBRIDS WITH DOMESTIC PIGS

Wild Boar (Sus scrofa) x Domestic Pig (Sus scrofa domesticus / Sus domestica) hybrids are common and partially fertile despite the parent species’ different chromosome counts (38 ikn the domestic pig, 36 in the wild boar). Wild board are very variable with numerous local races. Boar–pig hybrids bred from Eurasian wild boar and local domestic pigs are found wherever European settlers imported wild boars as game animals. Hybrids occur when domestic swine escape or when wild boar males break into pig pens, or when farmed hybrid sows escape. The fertile female hybrids can mate with either parent species but the appearance and temperament of the wild boar seems to be dominant. It’s worth noting that non-hybrid feral domestic pigs lose their domestic characteristics within a few generations and revert to wild appearance. They are raised for their meat, their pelts are sold as wild boar pelts. Hybrids can grow unusually large which makes then attractive meat-producers despite them being more aggressive than domestic swine.

Domestic Tamworth pigs (a bristly, red coloured "unimproved" breed) have been crossed with wild boar to create "Iron Age Pigs" which resemble early domestic pigs. The piglets have stripes or blotches like young boar. "Iron Age Pigs" are a common attraction at farm parks although the hybrids, which are less tractable than domestic swine, generally end up in sausages. Other domestic pigs have been crossed with American wild hogs to produce compact, hairy hog-like hybrids. In "The Variation Of Animals And Plants Under Domestication" Charles Darwin wrote: "The European wild boar and the Chinese domesticated pig are almost certainly specifically distinct: Sir F. Darwin crossed a sow of the latter breed with a wild Alpine boar which had become extremely tame, but the young, though having half-domesticated blood in their veins, were "extremely wild in confinement, and would not eat swill like common English pigs.""


Hybrid of wild boar and domestic pig at the Rothschild Zoological Museum.


Hybrid of wild boar and domestic pig at the Rothschild Zoological Museum.

Warthog (Phacochoerus africanus) x Domestic Pig (Sus scrofa) hybrids were reported in South Africa in 1786 by Anders Sparrman, Swedish naturalist, but the parentage was unverified and later attempts to cross these species were unsuccessful.

Bush Pig x Domestic Pig hybrids occurred in the Transvaal in the early 1970s when a domestic sow escaped from a farm and mated with a bush pig. The 8 offspring had bush pig traits and were said to be prolific. The Red River Hog x Domestic Pig (in the form of Eurasian Wild Pigs) may hybridise where the species come into contact in Burkina Faso, Gabon and Zaire.

There are numerous pig species on the island chain that ranges from the Andaman & Nicobar Islands in the Bay of Bengal at the northern end to Papua new Guinea at the south-eastern end. These islands include Indonesia, Timor, Java and the Phillipines. Many of these islands have their own local species (which arose through geographical isolation) which can interbreed with each other and with introduced domestic pigs.

Bearded Pig (Sus ahoenobarbus) x Feral Domestic Pig hybrids occur in the Malay Peninsula, Sumatra, Borneo, and several islands in the Indonesia archipelago. In East Java, the Domestic Pig probably hybridises with the Javan Pig (Sus verrucosus) as intermediate forms have been reported. The Sulawesi Wild Boar (Sus celebensis) x Domestic Pig hybrids form the common pigs of New Guinea and neighbouring regions. The New Guinea Pig (Sus papuensis) is probably a hybrid of these species when both species were introduced onto various islands by human settlers. On other islands the local pig species appear to be derived from either the Sulawesi Wild Boar or from the Domestic Pig; these now look very different from their ancestral species but are not hybrids. The Timor Pig (S. timoriensis) and Simeulue Island Pig (S. mimus) are derived from the Sulawesi Wild Boar. The Andaman Pig (S. andamanensis) and Nicobar Pig (S. nicobaricus) are derived from the Domestic Pig.

In the Phillipines several species of Warty Pig on the different islands hybridise freely with introduced domestic swine. In all cases there is a threat of genetic contamination to the native species. Domestic pigs are both free-ranging and feral animals and the hybrids may thrive better where the environment is damaged by human activity. Mindoro Warty Pig (Sus oliveri) x Domestic Pig hybrids occur freely on Mindoro Island. Philippine Warty Pig (Sus philippensis) x Domestic Pig hybrids occur freely. Visayan Warty Pig × Domestic Pig hybrids occur to such an extent that the Visayan Warty Pig risks being supplanted by hybrids. Bearded Pig (Sus barbatus) x Visayan Warty Pig (Sus cebifrons) hybrids may have produced the Palawan Bearded Pig (Sus ahoenobarbus) which has characteristics of both species. This would have occurred before the islands became isolated from each other.

MISCELLANEOUS AFRICAN SWINE

Giant Forest Hog (Hylochoerus meinertzhageni) x West African Forest Hog (Hylochoerus rimator) hybrids occur in the Congo (Zaire), but the parents appear to be subspecies rather than full species. The Bush Pig (Potamochoerus larvatus) x Red River Hog (Potamochoerus porcus) hybridise freely in contact zones in Zaire and Sudan.

DOMESTIC PIG X BABIRUSA

In 2006, hybrids between a domestic sow and a male babirusa were born at Copenhagen Zoo. The babirusa (Babyrousa babyrussa) or pig-deer is a pig-like creature found on Celebes (Sulawesi) and some other Indonesian islands. When Copenhagen Zoo's lone male babirusa showed signs of depression, the zoo provided two domestic sows as company in its enclosure. To their amazement, one of the sows gave birth to 5 small hybrid offspring. Although the two species share a common ancestor, this is so far back that it is at family level (the same level at which humans and chimps share a common ancestor). The zoo's assistant director, Bengt Holst, likened it to a cow and a goat producing offspring. One of the hybrids died soon after, but the the remaining 2 males and 2 females were doing well. Because the parents are so dissimilar, the zoo remain cautious about the hybrids' longevity and health prospects. Physically, the hybrids resemble the babirusa, especially in their teeth and skin colour. Their DNA is being examined.

PECCARIES / JAVELINA

Collared Peccary/Javelina (Dicotyles tajacu) x White-lipped Peccary (Tayassu pecari). These are types of wild pig from central and south America. Several hybrids were bred at the Regents park Zoological Gardens (London Zoo) between 1864 and 1883. The collared peccary (sire0 has 26 chromosomes, the white-lipped peccary (dam) has 30 chromosomes, the hybrids had 28 chromosomes. Male hybrids are confirmed to be sterile, but female hybrids may be fertile (untested).

ALLEGED RAM X SOW HYBRIDS (IMPOSSIBLE)

SUPPOSITIOUS HYBRID (The Field, 17th June, 1899). Having noticed in your issue of April 1 a letter concerning a supposed sheep and goat hybrid, I think that perhaps the following maybe of interest to some of your readers. Some three months ago a Mexican came to my ranche and asked me to lend him a pet ram that I had. On inquiring from him for what reason he might require it, I was dumbfounded by his answer: "I want it for a mate for a couple of sows I have." I volunteered to lend the one I had to him, but on hearing that it was a Merino, he declined my offer, saying that he thought it was a common Mexican ram. Naturally enough my curiosity was aroused, and I made it my business to inquire into the cause of such an astounding request. Not only from the man who asked me for the loan of my ram, but also from several other Mexican ranchmen near by, I elicited the following information:

That it was a well-known fact among Mexican rancheros that a common Mexican ram will cross with a sow, provided that the ram has been brought up by suckling a sow, in the same way as a donkey will cover mares if he has been nourished and run with a mare. The Mexicans around about here assert that the progeny of such a cross fatten much quicker than is the case with an ordinary hog —a considerable advantage, as it naturally entails a reduction in the corn bill. Whether this statement is a fact I cannot say; all I can vouch for is that I have been asked to lend a ram for such a purpose, and that any Mexican one may ask will maintain that such is the case — the greater number asserting that they themselves have owned several such (to my mind) curiosities. In fact, the headman who is in charge of my sheep at present has told me that he has owned several. He tells me that the offspring differ but little from the ordinary hog, except that the snout is distinctly shorter, and that under the bristles there is a thin coat of coarse wool. Before closing this I may add that, relating to the supposed sheep and goat hybrid mentioned in your issue of April 1, in my neighbourhood it is a recognised fact that there are such hybrids, and that it is of no uncommon occurrence, when sheep and goats run together, as is often the case among small ranching men on the Mexican frontier. I personally have seen several such hybrids, at least they have been pointed out to me as being such; and should it chance to be in any way interesting to any of your readers, I have np doubt I could procure you a photograph of one of the same. G.S. Zaragoza, Mexico.

[We insert our correspondent’s letter, not as accepting the account, but rather as a proof of the extreme looseness of the credence given to the existence of certain hybrids. The production of a hybrid between a sheep and a pig is regarded by all zoologists as perfectly incredible. Such hybrids were believed in before any advance in anatomical or zoological knowledge, but are now regarded by all scientific authorities as absolutely impossible. We may say that the belief in each an animal throws greater doubt than ever on the production of the goat and sheep hybrid. Our correspondent kindly offers to send us a photograph of one of these supposed animals, which we shall examine with interest, although a mere photograph cannot offer conclusive evidence. As stated in the letter of Mr Tegetmeier inserted in our issue of April 1 1899, the tangible distinctions between the sheep and the goat, as distinct species, are that in the sheep there are glands between the toes in all the four feet, and the males are not odorous, whereas in the goat the glands are only present in the forefeet, and the males are strongly odorous. In these supposed sheep and goat hybrids it would be very desirable to determine not only the location of the foot glands, but also the presence or abeam of odour in the males.—ED.]

SUPPOSITIOUS HYBRIDS. (The Field, 19th August 1899). SIR,—l am writing to you in reference to an article in the Field of June 17 1899, under the heading " Supposititious Hybrids." I am not good at letter writing, or should have written to you some years ago on the subject of the crossing of Mexican rams and sows. In spite of the ridicule that you throw on the subject, I can assure you that it is a fact, and I can prove it to anyone who cares to spend enough time in the country. My neighbour, old Don Pablo Melendres, for years kept a ram for no other purpose than that of covering his two sows. I have known Americans come here, and at first ridicule the idea, but they have gone away convinced. I can bring witnesses ready to swear before a notary public to the truth of what I claim. I do not take in any English papers (for financial reasons), but friends keep me pretty regularly supplied with the Field, and I have once or twice seen subjects doubted that I might have helped to clear up, but since I left Wellington College, Berks, some sixteen or seventeen years ago, I have not had much occasion to put pen to paper, and the fear that I should not be sufficiently concise or clear has deterred me. I shall be glad to give you all information in my power. J. C. R., Dofia Ana Co., New Mex., U.S.A.

THE CUINO - A SUPPOSED HYBRID. (The Field, 22nd February 1902) SOME TWO YEARS SINCE the subject of the possibility of hybrids being produced between two distinct species of animals more or less different in structure and habits was ventilated in the Field, and articles appeared written by myself and others, denying the existence or the possibility of the production of many of these supposed hybrids. In the Field of Sept. 29, 1900, was published an article which had been sent to it by Dr Marshall of Charlemont, Virginia. It was extracted from the Breeder's Gazette, a paper holding a very high position in the states. It related the full and circumstantial details of the production of a hybrid called a cuino, a cross between the sheep and the hog. The fullest and, apparently, the most practical details were given as to the production of these hybrids, their description, their use, their fertility with the ram, and the whole of the practical details respecting their growth, appearance, and management. In remarking on this paper, whilst giving the writer every credit for good faith, I stated that no physiologist could possibly accept such a statement without the most irrefragible proof, the structure of the animals being too diverse. Some months later a letter came to hand from another correspondent, an Englishman residing in Mexico, endorsing the account, and stating that he and his partner were having such animals reared on their estate, about fifteen miles away from the town in which they lived. In this letter the details of the production and management were repeated ; and it was so obviously written in perfectly good faith that I had only one reply to make - that if my correspondent could forward a specimen of this singular production it would be the only means of settling the question. I have recently received from this gentleman a letter from which I may take the following extracts:

I wrote to you some months ago on the subject of hybrids from the southern part of Mexico. You will receive with this the skull of one of the hybrids mentioned . . . . which will enable you to decide whether there is any trace of sheep parentage in it. I sent a leg of the animal to a neighbour, a Scotchman whose business is in cattle and pigs, and he wrote to me thanking me for the “leg of mutton." His wife, an American, on eating it, asked what the meat was, as it was as dark as mutton, and yet cooked like pork. A friend of mine near the city of Mexico writes to me that he had succeeded in getting the hybrid to cross with the ram. I am going to see him as soon as I can, and if his statement is true, I shall advise you of the fact.

As this cuino is bred with the greatest care entirely apart from the other pigs, and in large numbers in America, where its gestation is said to be seven months and not four or five, as in the case of the sow and sheep, it was worthy of careful consideration, and I was very glad to receive the skull, but, as I anticipated, it has no hybrid character about it whatever. It is purely and simply the skull of a pig. Without stopping to enter into such details as the character of the orbit, or the articulation of the lower jaw, which are utterly distinct in the sheep and in the pig, I need only call attention to the teeth in the fore part of the upper jaw. These are present as in the pig, and perfectly developed, whereas in the sheep, as every anatomist knows, the fore part of the jaw is utterly destitute of teeth, there being only a horny pad against which the lower incisors act. No zoologist could for a moment regard the skull as showing the slightest trace of ovine structure. In order to obtain corroboration of these facts I exhibited the skull at the last meeting of the Zoological Society, and its true character vas recognised by every anatomist and zoologist present who noticed it.

The production and existence of this supposed hybrid is one of those remarkable circumstances which show how readily falsehood is accepted in the place of truth ; but we cannot afford to laugh at the blunders of the American breeders when we recollect that similar mistakes have occurred in this country ; and even in our own Zoological Gardens the existence of a hybrid between the hare and the rabbit was at one time believed in and experimented upon, until it was demonstrated that no such animal existed. This belief has long passed out of existence in this country, but in America , as the Field has often pointed out, the hybrid production of the Belgian hare rabbit was recently, and possibly is now, thoroughly believed in, and large sums are given for specimens of so called hare-rabbits , the animal being simply large variety of the domesticated rabbit. W. B.

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