Common Hamster and Golden Hamster have mated and resulted in pregnancy in a Female Golden Hamster, but no offspring were born. Golden Hamsters and Romanian Hamsters produce sterile hybrid offspring which are intermediate in type. Campbell's Dwarf Russian Hamster hybridizes freely with the Siberian Hamster (Winter White Russian Dwarf Hamster) and produces fertile hybrid offspring; these may be sub-species.

Norway (Brown) Rats and Black Rats will mate and will produce live offspring, but the offspring die shortly after birth.

Among the Jirds (a type of gerbil), many of the Shaw's Jirds kept as pets in the UK are apparently hybrids between the Shaw's Jird and Libyan Jird (they are known as UK Shaw's Jirds to differentiate them from the true species). Hybrids exist between the Pallid Gerbil and Cheesman's Gerbil. Although rodent fanciers may deplore the hybrid strains or try to segregate the species, nature is not always observant of human-declared species boundaries!

For those interested in laboratory rodents, there are also natural and artificial hybrids between different European mice (Mus musculus x M domesticus, M musculus x M castaneus) and laboratory hybrids between mice (M musculus x M spretus, M musculus x M spicilegus, M musculus x M macedonicus) However other mice could not hybridise with M musculus. M musculus x M caroli hybrids were either stillborn or failed to thrive after birth. M musculus x M cervicolor did not get beyond early embryo cell divisions. M musculus x M dunni also failed early in embryo development. Of those mouse hybrids that thrived, the male was sterile, but the female was fertile. There are also hybrids between the East European Vole and Common Vole.

According to a publication in 1911, crosses were made between the common rabbit and the guinea-pig and were exhibited in the Zoological Gardens of Sydney, New South Wales. There have been several claims of rabbit/cavy (guinea pig) crosses since then.


THE HARE (The Field, 6th June 1896) “The Natural History of the Hare” by the Rev. H.A. Macpherson […] The problem of the inter-breeding of the brown hare and blue hares (Lepus timidus and L. variabilis) [Mountain hares] has never been satisfactorily determined. Mr Macpherson deals with it in the following extracts, which we present to our readers as a fair summary of what is knows on the subject :

More than forty yearsi ago a Russian zoologist, Middendorf, drew the attention of naturalists to the fact of the brown hare of the low ground interbreeding with the blue mountain hare, and producing fertile offspring. I do not know why this should not often take place. The blue hares keep to the tops of our moors all through the summer, it is true. In snowy weather they often descend to the low grounds ; and it sometimes happens that a stray individual chooses to pass the following summer on the land to which she migrated in late autumn. An intelligent keeper in the service of Macleod of Macleod assures me that hares which he believes to le hybrids have been killed repeatedly on the shooting in his charge, and reports of others have reached me from different quarters. The blue hare is now common, even in the lowlands of Scotland. Of course, the chance of her hybridising with her brown or red neighbour becomes more considerable as her breeding range extends.

Professor Fatio states that the brown hares which live among the Alps often come into contact with the blue hares of higher altitudes, and apparently the two species interbreed. The hybrids resemble both their parents in the character of their pelage, but are inferior in size to pure-bred animals. The ears and the tails of each hybrids are constantly rather shorter than those of the common hare. Fatio has himself examined these animals; they were procured in the Bernese Oberland and the Valais. Professor Theobald repeatedly received hybrid hares from the Oberhalbstein, and even kept one of them alive for a considerable period.

This subject has not received its proper share of attention from Scottish naturalists ; but further research may prove, perhaps, that these blue and brown hares do, In some rare and exceptional instances, interbreed. Mr Lumsden exhibited a hare before the Glasgow Natural History Society. It had been shot in December 1876, near Dumbarton Moor, upon which blue hares had been turned out a few years previously. Mr J. Cordeaux shot a similar animal in Perthshire in September of the same year. "This example, which he compared the same day with pure specimens of both species, exhibited very distinctly the mixture of colours of both parents, that of the common hare predominating. It differed also in some respects from the mountain hare, being generally larger, with larger head, larger ears, and broader forehead. The head keeper on this moor, an experienced man, stated that there was no doubt whatever about the interbreeding of the two species, but that the progeny was infertile.” I may perhaps take this opportunity to express the hope that if a reader of these lines should happen to have the good luck to come across an apparently hybrid hare he will send it to the Natural History Museum, so that its creditable may be fully investigated by a professed expert _The opinions of amateurs are seldom, if ever, considered final in such difficult matters.

We can hardly agree with Mr Macpherson that the examination of a specimen by the authorities of the Natural History Museum, would settle the matter. There are no definite marks of hybridity. The careful examination and measurements of a specimen forwarded to the Field and submitted to Mr Tegetmeier were recorded in Sept. 1, 1894, but they were not regarded by him as settling the question. Whether or not the two species, interbreed can only be satisfactorily determined by mating the two species in confinement.

[In fact studies in northern Europe show that the mountain hare/blue hare (now classified as Lepus timidus) and brown hare (now classified as Lepus europaeus) hybridize freely and frequently and produce fertile offspring, resulting in gene flow across the species barrier. Gene flow tends to be from the mountain hare into the brown hare population rather than vice versa. The extent of hybridisation is important because the warming climate means the brown hare is continuously expanding its range northward, at the expense of the mountain hare, and the hybrid offspring may eventually displace the mountain hare.].


In "The Variation Of Animals And Plants Under Domestication" Charles Darwin wrote: "But from what we hear of the marvellous success in France in rearing hybrids between the hare and rabbit (See Dr. P. Broca's interesting memoir on this subject in Brown-Sequard 'Journ. de. Phys.' volume 2 page 367.), it is possible, though not probable, from the great difficulty in making the first cross, that some of the larger races, which are coloured like the hare, may have been modified by crosses with this animal. Nevertheless, the chief differences in the skeletons of the several domestic breeds cannot, as we shall presently see, have been derived from a cross with the hare [...] The common hare [...] has crossed with the rabbit. (Although the existence of the Leporides, as described by Dr. Broca ('Journal de Phys.' tome 2 page 370), has been positively denied, yet Dr. Pigeaux ('Annals and Mag. of Nat. Hist.' volume 20 1867 page 75) affirms that the hare and rabbit have produced hybrids.)"

This appeared in The Field No 2887, April 25th, 1908: "Alleged Hare-Rabbit Cross - about four years ago, in reviewing a book on rabbits in the Zoologischer Garten, Dr Brettiger, the editor, drew attention to the lack of positive evidence on this subject. In the current number, Herr Elffe, of Hamburg, challenges the editor's view and describes what he believes to be cases of hybridity between the hare and the rabbit, and the fertility of some of the hybrids, which are said to breed twice in the eyar, and to throw blind, naked young. According to the author, the hybrid race was founded five years ago and some of [the animals] are said to be still living in Hamburg. In these circumstances, the matter seems to call for investigation." However, it was noted that Herr Elffe brought forth no evidence in support of his statements and that wild rabbits frequently bred with fancy rabbits.

This debate over hares and rabbits interbreeding was mostly played out in the pages of "The Field."

THE HARE AND RABBIT CROSS. (The Field, 4th January 1862) As the discussion of the hare and rabbit question has been revived, perhaps you will and room for the following. But I premise, by admitting that the account may be very imperfect, as part was derived from hearsay and part from my own observation. During the summer before last there arrived at the Zoological Gardens, from France, what was said to be a hybrid hare-and-rabbit buck. I saw this animal, and he appeared to me nothing more than a large sandy-coloured rabbit. He was put to a common doe rabbit, more than once, I believe, and the produce were exhibited in cages labelled "Hybrids between the hare and rabbit." I frequently visited and examined these animals, and they certainly appeared to me to be different from the common rabbit, both in size and other respect; for instance, some, though not all of them, exhibited that constant twitching movement of the nose and upper lip which is peculiar to the hare, though not to the rabbit; and, moreover, they did not commence breeding inter se till five or six months after the time that common rabbit usually do. At a meeting of the Zoological Society last spring, a report of the proceedings of which was not published in the ordinary daily or periodical journals, cold water was thrown on the question, by its being announced that the pedigree of the original buck had never been ascertained; and in fact it was considered that the statement that he was a hybrid was mythical. The experiment was therefore looked upon as invalid, and of no effect; or, to use a more scientific phrase, the experiment was not a capital one. As I have said above, a great part of this may be erroneous, and if so I shall be too glad if anyone competent to do so will correct me. – ALASTOR. [We entertain grave doubts as to the possibility of obtaining a hybrid between the rabbit and hare. We are well aware that these so-called hybrids are often on sale in Leadenhall-market; but no enquiry will elicit any more than the statement that they come from France. The progeny of these so-called hybrids are born blind and naked, just like ordinary rabbits. – ED]

THE HARE AND RABBIT CROSS. (The Field, 18th January 1862) I have to regret that you differ from me as to the possibility of the hare and rabbit cross. I have already stated my reasons why I believe the cross to have been already effected—it is unnecessary to repeat them. If success may be looked for in the cross between eland and cow, surely it may be between the hare and rabbit. The former belong to different genera, to which latter certainly do not. As the subject of crossing is being, and is likely to continue to be mooted in your columns, it may be interesting to give some of the ideas of the great American naturalist, the late Professor Morton, on the subject. His opinion was, that "hybridity must not be treated as a unit, as its facts are as susceptible of classification as any other series of physiological phenomena." He therefore divided the examples of species into remote, allied and proximate; 1st, remote, that in which hybrids never reproduce, where the mixed progeny begins and ends with the firer cross; 2nd, allied — that in which the hybrids are incapable of reproducing inter se, but multiply by union with the parent stock; 3rd, proximate — that in which animals of unquestionably distinct species produce a progeny which is prolific inter se."

I am inclined to think that the cross of horse and ass, and likewise that of the eland and cow, should it succeed, would come under the first category. That from what is known of the cross of the wolf and dog, that would apply to the second. And should the cross of the hare and rabbit and the progeny be fertile inter see, that that would apply to the third. "Nemo" [another correspondent] would seem to doubt the hybridity of the 'leporines’ mentioned in his letter, because, like the rabbit, they tear their fur for the nest, and the young are born blind and naked. It must be recollected, in the first place, that the father was not a true hare; but if he had been, I conceive the produce might have inherited the habits and physiological peculiarities of the mother; and what strengthens me in this opinion In the following, viz , Sir C. Lyell says. " It seems rarely to happen that the mule offspring is truly intermediate in character between the two parents. Hunter mentions in his experiments (with the wolf and dog), that one of the hybrid pups resembled the wolf much more than the rest of the litter; and we are informed by Weigmann, that in a litter lately obtained in the Royal menagerie at Berlin from a pointer and a she-wolf, two of the cubs resembled the common wolf-dog, but the third was like a pointer, with hanging ears. There is undoubtedly a very close analogy between these phenomena and those presented by the intermixture of distinct races of the same species, both in the inferior animals and in man. Dr. Pritchard, in his ‘Physical History of Mankind,’ cites examples where the peculiarities of the parents have been transmitted very unequally to the offspring, as where children, entirely white, or perfectly black, have sprung from the union of the European and negro." I think these instances bear strongly on the case of the leporines.— ALASTOR.
[We shall always be willing, we may say delighted, to publish either fact or opinions on this most interesting subject; but we think we are merely acting with necessary caution when we state our own grave doubts as to the success of the experiment. These double are based on physiological difficulties, and are confirmed by the examination of what are called "leporines," which appear to us to be a breed of rabbit. having the size and somewhat the colour of hares. Every facility for trying the experiment of rearing these hybrids is within reach: let our correspondents who are believers, work out the problem for themselves and record their success in these columns. The publication of each success would be gratifying alike to the Editor and his readers.—ED]

THE HARE AND RABBIT CROSS. (The Field, 18th January 1862) l am obliged to your correspondent "Nemo" for his pertinent remarks upon hybridisation, and I gladly answer his queries. My relative, Professor Bell, in his work on “British Quadrupeds," pp. 389-90 makes the following observations: It is well known that there are many instances of animals, undoubtedly distinct, producing young, which become fertile in conjunction with one or other of the parent kinds. This has been proved in the case of several species both of gallinaceous and natatorial birds, in a domesticated state; but there is not, I believe, on record, a single instance of a male and female of such hybrid progeny being mutually fertile. On the other hand, the production of sterile hybrids between distinct species of the same group is a circumstance so commonly occurring as to require only an allusion." Mr Bell remarks further on. – “The mule has been known occasionally to produce young with the horse or the ass; these cases, however, are extremely rare, and serve as illustrations of the statements which I have already made, as there is no Instance on record of two mules having bred together." In a foot-note an instance is then given in which a hybrid between the zebra and the ass impregnated a mare, and she produced a foal with some stripes like the zebra. I believe entire reliance may be placed on the foregoing quotations. I happen to know that Mr Bell took very great pains to investigate this subject for himself, and to be satisfied of the truth of asserted facts before he committed himself to the above statements.

Your correspondent is surely in error when he says that none of the progeny of jungle-fowls and bantams are hybrids, and that they are simply equivalent to a cross between a game cock and a Cochin China hen. His argument Is that they are not hybrids because “both the parents are fowls." He might as well say that the offspring of the interbred common pheasant and golden pheasant are not hybrids because both, the parents are pheasants. [. . .] – JAMES SALTER

THE HARE AND RABBIT CROSS. (The Field, 18th January 1862) It is very unsatisfactory that the discussion on the "leporine" question should have only resulted in negative conclusions, and the evidence in favour of the supposed cross should always fail just at the critical point of inquiry when it is asked, "Who can vouch for it?” I have, as yet, failed to learn that any one of the communications sent to the reputed breeder of these leporines has been productive of a conclusive reply; indeed, I have heard that the maire of Angouleme denies to that city the credit of producing the supposed cross. I give only a rumour, but hope before long, to test its truth. The leporines in the Zoological Gardens must be familiar to many of your readers. I will, however, offer a few remarks about them, and the points In which they are said to differ from rabbits and resemble our common English hare. Much stress has been laid on the fact of the young leporines squealing when handled, and, so far, resembling the hare; but it turns out that, if not rudely seized, three young animate are as silent as tame rabbits. Moreover, many persons now recollect that wild rabbits, both old and young, are apt to complain loudly when injured or roughly treated. The vocal character, then, cannot be trusted; or even regarded, as evidence in this case. The great wildness of the young leporines lhas also been noticed as indicating some wild blood in their veins. They become tame enough, however, as they grow up. This is consistent with what might be expected from the produce of a union between wild and tame parents, especially if the young are kept in confinement ; but it leads me to throw out a suggestion, and to inquire, ‘What sort of animal should we get, and with what manners, by crossing the wild grey rabbit and the tame yellow one?’ Has it ever been done, or attempted'? if such animals are known, are they very unlike “leporines."

“Alastor's " discovery of the twitching of the nose being “peculiar to the hare" is likely to remain his own property. Any schoolboy could teach him better; and if he likes to pay another visit to the Zoological Gardens, he may there see the English and Scotch hares, the leporines, and two or three varieties of the tame rabbit, all twitching their noses in the same nervous, irregular manner. I may venture to say the wild rabbit does so likewise. Dr. Crisp has examined the anatomy of one of the produce of a leporine and a tame rabbit, and found the viscera essentially the same as in the latter animal; the hair, however, even in that three-quarters-bred rabbit he believed to have a “hare like character." I must be permitted to doubt If much reliance can be placed in a character which varies slightly even in different breeds of the rabbit, and yet does not present any very marked distinctions in the several species of the genus. An examination I have just made of the fur of the common hare, leporine, wild and tame rabbits, has satisfied me that the distinctions between them are very nice [small] ones—not so great as in wool from different breeds of English sheep. The under fur has essentially the same form and appearance In the four animals; but the long, interspersed hairs in the leporine resemble, in the distinctness of their cells, those of the wild rabbit more than those so conspicuous in the hare.

There Is one point that has been suggested to me with reference to the origin of tine leporine, and it appears worth considering. Is the hare spoken of as having been crossed with the rabbit, the common English hare? It may not be generally known that the Scotch hare makes a nest, and produces its young in the same naked and helpless condition as does the rabbit. Probably other species of hare on the Continent may have the same habits; at all events, if we exclude our common hare, the difficulty supposed to exist in producing a cross between two species of the genus Lepus may not be insurmountable. I am not inclined to believe in such a hybrid, but, in discussing the question. I am anxious to put both sides fairly. In the Zoological Gardens we have had a Scotch hare and a tame rabbit associated for the last three or four months; they have been very good friends so far; and the breeding season will probably determine the question of love or hatred between them. An experiment tried during the last year, with the object of producing a cross between the English hare and tame rabbit, terminated, after a few months, by the rabbit hall killing her companion; and a doe hare, which was to have been tried with a buck rabbit, unfortunately died before she had been very long in the menagerie.

The leporine breeds freely with its own kind, and without difficulty with the tame rabbit. I think it will be no easy matter for any one to point out a single essential hare-character in this so-called leporine. Its breeding habits, anatomy, the colour and flavour of its flesh, the character of its fur (grey at the roots, as in the rabbit, not white, as in the hare), and, altogether, the general appearance of the animal, point to the conclusion that only rabbits' blood flows in Its veins; that it Is, in fact, a new variety of that well-known species - although I am told that a large game-dealer in London has been acquainted with them for a long time, and has sold them here and at Paris under the belief that they were nothing but large rabbits of a particular breed.

Whilst holding the opinions I have here expressed, I may say that I hope further experiments will be tried with the hare, both In London and the country. The point in dispute will not be fairly settled until the experiments have been tried under various conditions, and with different species, both of hare and rabbit "Alastor" is indignant because more attempts at cross-breeding are not made in the Zoological Garden, and then encourages the society by telling them he has little confidence In what they have done, even when successful; but "Alastor," who knows the gardens well, shows by the way he writes, that his knowledge of the requisite conditions for breeding wild animals in confinement is as limited as his acquaintance with rabbits' noses. Plenty of room, and plenty of quiet, are the first requisites for breeding wild animals in confinement; and these are just the conditions which are not to be obtained In such a collection as there is In the Regent’s-park. The wonder is, that any breeding goes on there at all, still more that any hybrids should be produced.— E. W. HOLDSWORTH — P.S. In a case of which I have heard, of a wild grey rabbit pairing with a tame black one, the produce consisted of one or two black and several grey animals. There was no mixture of the two colours in any of the young ones.

LEPORINES (The Field, 1st February 1862)
INTEREST now generally felt in the question of hybridism, especially in the reputed successful interbreeding of the hare and rabbit, induces me to send you an abstract of an important paper on the subject, which I have met with in the course of my inquiries about the experiments at Angouleme. This paper is one of a series of four memoirs, by M. Paul Broca, "Sur l'Hybritie et sur les Metis du Lievre et du Lapin," and published in the Journal In whose editor is the well-known physiologist, Dr. E. Brown-Sequard. In the first two memoirs N. Broca discusses the probable origin of the different races of dogs and men; in the third, published in July 1859, he gives an account of the production of leporines, and his concluding paper is devoted to the results of hybridism, or interbreeding among the various types of the human race. I shall confine myself to that embodying his observations on the hare and rabbit cross; his remarks being chiefly founded on the experiments carried out by M. Roux, at Angouleme, which had been made the special subject of his investigations.

Before speaking of the leporines, M. Broca makes some remarks on other authenticated hybrids, and points out that M. Chevreuil was mistaken in disputing the Rev. John Bachman 's statement of the fertility of the cross between the goat and sheep. Everyone who, under suitable conditions, had repeated the experiments of Buffon, had succeeded in producing such fertile hybrids; and if similar attempts in the Jardin des Plantes had failed, it was probably because, being kept closely confined, the animals had not enjoyed sufficient liberty ;* but whenever a he-goat had been folded [penned] with sheep, alliances and fertile hybrids had been the result. The author then refers to the success which has attended this cross-breeding in Chili, where thousands of pellions, or the skins prepared with the wool on, are annually exported to Peru. These animals, as well as their skins, are called pellions in Chili, but are known elsewhere as chabins and are the produce only of the male goat and the ewe, the best wool being procured by recrossing the first generation of chabins with the sheep.

[*In a note, the author says:- “I have authentic Information that many species of animals, though kept pure, become barren after three or four generations at the Jardin des Plantes. Domestication rarely diminishes the fertility of animals, and even frequently increases it; but it appears that want of exercise, or the nature of their food, may, in many cases, impede reproduction. Perhaps, also, in the experiments at the Museum, the union of near relations has not been sufficiently avoided.]

After referring to the more or less fertile hybrids between the camel and dromedary, the llama family, the wolf and dog, &c., and among several species of birds. M. Broca says the decisive experiment must be made with nearly-allied animals, living in a wild state in the same country, but with different instincts, which prevent their crossing whilst in a free condition. These requirements the author believed to be perfectly satisfied in the case of the hare (Lepus timidus) and the rabbit (Lepus cuniculus). No one, he says, can doubt these two animals being specifically distinct. They certainly differ lees in their anatomical characters than many animas reputed to be of the same species; but their instincts, tastes, and habits are so opposed that it is impossible to confound them. The hare is solitary, the rabbit gregarious; the hare lives above-ground, and hides in the brakes; the rabbit burrows, forms subterranean colonies, where each family has its nest, and the young are sheltered during lactation. Gestation lasts thirty days in both species (?), but the hare has only two or three litters in the year, and from two to four young one, in a litter. The rabbit bears eight times annually, and on each occasion produces at least four young - usually six or eight - often more. The rabbit was early and readily domesticated. Young wild rabbits are constantly captured, and easily tamed. They reproduce in confinement, and become domesticated in the second generation. All attempts, however, to domesticate the hare have entirely failed : some have been tamed, but have very rarely bred, and their descendants have been nearly barren. This sterility is complete in the female. Pregnant hares have been captured, and their young, born in captivity, reared artificially, but have failed to reproduce. The two species are natural enemies. The hare avoids the rabbit, and, although stronger, is generally worsted in a combat. Sportsmen well know that where rabbits are abundant there are few hares; and, if the latter are to increase, the former must be destroyed. These distinctions with others, external and internal, cannot be attributed accidental influences, and no one has even imagined that two species so distinct could have had a common origin; yet they can be crossed, although only with the greatest difficulty.

Buffon's unsuccessful experiments are then referred to, but M. Broca points out that in those cases no union was effected between the male hare and doe rabbit; with the contrary arrangement coupling took place, but there was no produce. The first decided success in crossing the hare and rabbit appears to have been obtained in 1774, and an account of it was published at Milan in 1780. In this instance a young female hare was reared in company with a young rabbit of the opposite sex by the Abbe Domenico Gagliari, at Maro, in Northern Italy. When about seven months old, the hare produced two young — one resembling the mother, the other like a rabbit ; a litter of four was afterwards born, and all the hybrids grew up. Some time after the rabbit died, but the hare continued to breed with her descendants, and they also reproduced inter se. The naturalist Carlo Amoretti investigated this case of fertile hybridism, and published an account of it at Milan, in a work devoted to science and art. M. Broca considers this experiment well authenticated, and says it is Impossible to exaggerate its importance. He comes then to the experiments at Angouleme, conducted by M. Alfred Roux, president of the Agricultural Society of Charente.

The first attempts by M. Roux were made in 1847, but it is only since 1850 that he has seen his way clear, and proceeded on a regular system. The results he has obtained may be considered definite. These results are known to all the inhabitant,. of Angouleme; they are as important from an economical as from a scientific point of view, and yet, strangely, remarks M. Broca, they have not yet been published. Chance alone, in 1857, made M. Broca acquainted with them, and soon afterwards he went to Angouleme to see for himself. In March 1859, he writes "Now the establishment of M. Roux is in full prosperity. I have just made a second journey to Angouleme to satisfy myself; the leporines are in their tenth generation. The hybrid race is by no means etiolated, and the produce, on the contrary, are liner than at first. They are superior in beauty, strength, and size to the two species whence they derive their origin. Apart front all scientific consideration, M. Roux has, then, obtained one of the most important practical results. He created a new race which promises to be of great service, and which probably will soon become generally distributed.”

But if the practical experiment was concluded, there was still something to be desired by science. M. Roux only endeavoured to produce the most profitable race, without considering the question of species, or the requirements of physiology. These points M. Broca takes under his own consideration after a long series of experiments have been tried. He now proceeds to describe what he saw and heard at M. Roux's establishment, and states that he cannot question the truth of M. Roux's information. It is found that when a full-grown male hare and doe rabbit are placed together, the two animals usually fight to the death, or, if not, they never unite. Coupling does not even take place if animals only three or four months old are brought up together. It is necessary to take male leverets three or four weeks old, when they can leave their mother, and bring them up with domesticated rabbits of the same age, and to separate them from every other animal of their own species. The male rabbits, never having known their natural partners, believe the hares to be such, and vice versa. The young hares become accustomed to confinement, and, under the influence of example, lose part of their wild instincts. When full grown, the hares must be separated from one another, and one or more of the doe rabbits, reared in their company, given to them. The cross is then effected without difficulty. M. Roux bad not tried the buck rabbit with the doe hare.

The domesticated rabbits chosen by M. Roux for his experiments naturally produce from eight to twelve young in a litter; united with the hare, they rarely have more than eight little ones, sometimes only five or six — the number being generally intermediate between those of the parents. To effect the crossing at his will, and not to exhaust the hares by too frequent unions, M. Roux separated them from the rabbits when they had once performed their duties. He also isolated, in as many separate cages, the females he intended for them. When he wished to effect the cross, be placed the hare at nightfall in a cage with a rabbit in heat, and withdrew him the next morning. That invariably sufficed. Union took place as certainly as between two rabbits. But it was observed that the hare — more continent or timid than the rabbit — never united by daylight, or even at night, if it saw anyone near. M. Boux was therefore obliged to go behind the cage, and await with patience, and in silence, the particular moment. He was thus enabled to ascertain that — unlike the buck rabbit, or even the hare in a wild state—the tamed hare was very gentle in his advances to his strange partner. The leporines of the first generation resemble the rabbit much more than the hare, and, altogether, might be easily confounded with rabbits. No advantage was gained by propagating this race. They bred inter se, and also with the rabbit; and in the latter case, the produce appeared almost identical with the pure species. M. Roux believed this return to the rabbit was without any practical utility. It was, however, otherwise with a return to the hare. The leporines, the issue of the hare and a female of the first cross, are finer, stronger, and larger than the animals of the pure species. These new hybrids, although three-quarters hare and one-quarter rabbit, appear directly intermediate between the two species, so that it may be said, other things being equal, the rabbit impresses its characters on the leporines more strongly than the hare. M. Broca calls these hybrids "quadroons" (quarterons), and says they are fertile inter se, but not very prolific — in this respect approaching the hare. Their litters consist only of from two to five young, and to obtain a more productive race, M. Roux determined to re-cross them with the first generation of hybrids. This union results in a breed five-eighths here and three-eighths rabbit, and is the one to which M. Roux gives his principal attention. The "three-eighths," as M. Broca designates this race, are quite as fine as the quadroons, and much more prolific. Their litters contain from five to eight young, which are reared without any difficulty, and are as hardy as the pure rabbit. They grow rapidly, and are capable of reproducing when four months old. Gestation lasts thirty days, and the young are suckled about three weeks. The female again receives the male seventeen days after littering. She may thus without difficulty bear six times in the year. This breed of leporines costs the least to bring up, and produces the most flesh for a given quantity of food ; it consequently makes the best return.

M. Broca takes the weight of the domesticated rabbit and that of the hare reared in confinement as being each about 6lb.; the " three eighths" leporine, he says, when a year old, or sooner, weighs from 8lb. to 10lb., many reach 12lb. or 14lb., and one has attained even 16lb. Leporines, at four months, are worth two francs each - double the price of the domesticated rabbit; and as they grow older the fur becomes very valuable, since it is finer than that of the hare. The author points out one curious character in the ears of the leporine. The young of all these breeds have one ear erect, the other hanging down; this peculiarity disappears with age in animals of the first cross, but is more decided and persistent as hare-blood increases.

Albino and Angora varieties are sometimes produced among leporines as among rabbits, but they are not so frequent; the albinos have not been allowed to breed, as they are considered inferior animals. The angoras have been permitted to unite, but they do not breed readily; their litters are small, and the young are not always angoras. All leporines, of whatever breed, have the flesh like that of the wild rabbit, that is to say, hardly deeper in colour than that of the domesticated rabbit; and the quadroons themselves, in this respect, are nearer the rabbit than the hare. It is worthy of remark, that the influence of the rabbit is even here predominant. The flesh of the leporines, however, has not the taste of either the wild or tame rabbit; it has a peculiar flavour, which is not unlike, says M. Macquet, that of the wing of a turkey. M. Roux has succeeded in producing leporines with only one-eighth rabbit in them, but only two were produced, and the experiment was not continued. M. Broca, however, expresses his intention to try some of his own experiments in this direction, with the view of ultimately obtaining a pure domesticated hare.

Upon the whole, continues Mr Broca, although M. Roux has not satisfied all the requirements of physiology ; though he has not entered in a register the particular genealogy of each of his leporines; though he has not been anxious to perpetuate especially the hybrid race of the first cross, and has preferred, with an exclusively practical purpose, to cross it with that of the second blood, to create the more productive and more lucrative race of the "three-eighths," everything tells us that the cross of the male hare and female rabbit constitutes an example of hybridity fertile inter se (eugenesique). Never, in uniting the hybrids of different bloods, either among themselves or with the others, has M. Roux found an instance of sterility. The limits of the fecundity of the first generation of hybrids are not ascertained, but it is known that the fertility of the three-eighths has continued for ten generations.

M. Broca is willing to admit, if desired by the advocates of the permanence of species, that the hybrids of the first generation have not been sufficiently studied; but, he asks, "What will they gain by the concession? Will there not always remain, between the two primitive types of the hare and the rabbit, the intermediate and lasting race of the three-eighths; a new race which returns to neither of the parent species, and which, fruitful with both, fertile also among themselves, will henceforth oblige zoologists either to throw into one species hares, rabbits, and leporines — a thing perfectly absurd — or else to confess that new types may be produced by crossing animals of entirely different origins; that species consequently are not inviolable, that nature has not raised between them insurmountable barriers, and that in short the classic doctrine of the permanence of species is altogether erroneous?"

M. Broca here concludes his account of the leporines. His object is to prove that crossing has produced several new races of animals, for he considers it impossible to attribute to climatic causes and accidental influences the formation of the races, so numerous and so diverse, which compose the family of domestic dogs ; and that of the races, quite as different and as numerous, of which the human family is constituted. These questions he discusses at length in his other papers. In the absence of direct information. I have before given my reasons for doubting the existence of the hare and rabbit cross; M. Broca’s statements, however, are, I think, conclusive evidence in its favour, and I believe I cannot act more fairly than by sending you the above abstract containing the essential details of M. Roux's successful experiments at Angouleme. – E.W. HOLDSWORTH

[Note: The “Belgian Hare” and “Flemish Giant” rabbit breeds are the descendants of the "leporine," and the leporine was not a rabbit/hare hybrid, but a cross between European wild and domestic rabbits, followed by selective breeding for size (for meat) or coat (for fur). The more reddish leporines resembled the European wild hare and was selectively bred to increase the resemblance, resulting in the Belgian Hare (although it is not a hare) which was bred in two types: the athletic-looking “showbench” version and a heavier meat-rabbit version. Other selective breeding of leporines for size resulted in the Flemish Giant.]

LEPORIDES, OR HARE RABBITS. (The Field, 29th February 1868)
THE so-called leporide, or hare rabbit, has recently been attracting some attention, a pamphlet having been published in Paris by M. Gayot, entitled, "Lievres, Lapins, et Leporides.” The same author has written on the subject in “La Chasse Illustree,” and “The Farmer” has also been devoting a portion of its columns to the consideration of leporides. I have read very carefully M. Gayot's article, and that in “The Farmer,” and I fail to see in either any proof of the existence of these animals. The opening paragraphs of the article in The Farmer—usually a very carefully edited paper afford a very good example of the manner in which certain pseudo-scientific views are foisted on the public. They are as follows "That there exists a breed of dogs known as the bull-terrier, and exhibiting in combination the characteristics of the two animals from which it derives its name, and that this breed possesses the power of propagating its species without degeneracy, is a fact as well known in France as in this country. One is apt to think that the knowledge of such a fact should have rendered it easy to French naturalists to believe in the existence, of another hybrid animal lately brought into notice - the leporide - a cross between the hare and the rabbit."

I will say nothing of the singular assertion that a breed of dogs exists between the bull and the terrier, which exhibits the characteristics of these two animals, as I do not believe that a hybrid between ruminant and a carnivore exists. But, supposing the writer to mean a cross between the bulldog and the terrier, the argument is perfectly worthless as proving the existence of leporides. The cross between two varieties of one species, as are the bulldog and terrier, is not, as is asserted, a species or a hybrid, but a mongrel, which by care can be perpetuated as a distinct breed. These mongrels are perfectly fertile inter se, or with either parent, and their existence has no bearing whatever on the production or perpetuation of a hybrid or mule between two distinct species of animal, such as the hare and the rabbit.

That animals so very different in habits and mode of life as the hare and the rabbit should interbreed is not very probable ; and if they did, there appears little doubt that the offspring would be a sterile hybrid. The young hare is born in a comparatively perfect condition, covered with fur, and able to see and move very speedily after birth. The young of rabbits, on the contrary, are much more numerous in each litter ; they are born in a very undeveloped condition, perfectly naked and sightless. That animals so diverse should produce fertile hybrids is not to be expected ; and I may state that all attempts to cross these two species at the Zoological Gardens have failed. The so-called leporides are nothing more than large brown rabbits, having the same period of gestation, number of young, and undeveloped, sightless condition at birth, that characterise ordinary domestic rabbits. The flesh is white, and totally destitute of the colour or flavour of that of the hare. I have recently examined microscopically, with much care, the fur of the hare, rabbit , and so-called leponde, and find that the fur of the two latter animals is apparently identical, and quite distinct from that of the hare. Unless some evidence very different from what has hitherto been made known is produced respecting the production of the leporide, there is no chance of its existence being recognised by naturalists. W. B. TEGETMEIER

ALLEGED HARE AND RABBIT CROSS (The Field, 25th April 1908) About four years ago, in reviewing a book on rabbits in the “Zoologischer Garten,” Dr Brettger, the editor, drew attention to the lack of positive evidence on this subject. In the current number Herr Eiffe, of Hamburg, challenges the editor's view, and describes what he believes to be cases of hybridity between the hare and the rabbit, and the fertility of some of the hybrids, which are said to breed twice in the year, and to throw blind, naked young. According to the author, the hybrid race was founded five years ago, and some of the leporides are said to be still living in Hamburg. In these circumstances the matter seems to call for investigation by the naturalists of Hamburg, and probably more will be heard of these reputed hybrids. It must, however, he remarked that Herr Eiffe brings forward no evidence in support of his statements. Quite recently Dr Gustav Brandes, of Halle-an-der-Saale, pointed out that while the wild rabbit bred freely with all the fancy races, the cross between the hare and the rabbit was highly improbable, and had never been established. Numerous attempts by Professor Kuhn at the Agricultural Institute in Halle to procure the cross with young hares and rabbits brought up together proved unsuccessful.

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