The Shetland Pony

by Charles Douglas; A. I. Douglas

The view that dwarfing is caused by inbreeding is insisted on by Sir Everett Millais in a book on Rational Breeding. Sir Everett states that, though in the case of the Shetland pony the “climate, bad food, &c., had been a factor in reducing the size, the primary cause was inbreeding due to isolation.”

It seems to me, however, highly probable that until artificial selection began in earnest about thirty years ago, inbreeding had little influence in determining the size of Shetland ponies—that isolation had been a decidedly more potent factor than inbreeding. Scottish red deer are decidedly smaller now than they were in Roman times; but this is not so much due to inbreeding as to the range of most of the herds being restricted, and to the best stags being cut off before they have a chance of improving the herd. The Scottish deer in New Zealand, though all descended from a few imported individuals, instead of dwindling in size, are larger and carry finer heads than their home-bred relatives,—the wider range and better conditions have more than compensated for the inevitable in-and-in breeding. It is doubtless true that in-and-in breeding sooner or later diminishes the vigour, size, and fertility, and, in addition, restricts variation. But under natural conditions, if the range is sufficiently extensive, occasional reversion to vigorous ancestors will prevent dwarfing provided there is rigid elimination of the unfit.

If Shetland ponies are the pigmy descendants of one or more ancient races at least as tall as Exmoor and Welsh ponies, one would expect them to increase in size when bred and reared under favourable conditions. It has been again and again asserted that “the climate and comparative privation of the Shetland Isles were necessary to maintain the small stature of the ponies, and that the breed would inevitably lose this and all other characteristics if bred away from Shetland and under more generous conditions.”

Some of the ponies recently brought south from Shetland have increased so much in size that, if otherwise eligible, they could not be registered in the ‘Shetland Pony Stud-Book’—i.e., they are now over 42 inches at the withers.[F9] The majority of these tall ponies, however, are piebalds or skewbalds, which in make and other respects resemble Iceland ponies,—if their history were traced, a piebald Iceland pony would probably be found amongst their recent ancestors. It is not surprising that young cross-bred Shetland ponies increase considerably in size when grazed on rich lowland pastures, or that now and again a pure-bred pedigree pony should grow above the recognised standard; but these exceptions only serve to prove the rule, now widely recognised by breeders, that pure-bred Shetlanders remain small however favourable their surroundings. Seeing that in the majority of pedigree ponies the dwarfing has gone so far that the metacarpals are actually shorter than in the remote three-toed Miocene ancestors, what is surprising is that there is not an immediate response to the stimuli which genial surroundings and abundant food imply.

[F9] In all probability these ponies would have measured over 40 inches had they remained in Shetland.

Some 500 years ago a female rabbit and her young were turned out on the small island of Porto Santo near Madeira. In course of time this island was so overrun with rabbits that it was for a time abandoned as a settlement. As the rabbits increased in number they dwindled in size, became reddish above and grey beneath, and lost the black marking from the points of the ears and the tip of the tail. Some of these Porto Santo rabbits which reached the London Zoological Gardens in 1861 reacquired the colour and markings of the common wild rabbit within four years. The Porto Santo rabbits having recovered the ancestral colours soon after reaching Europe, it might have been anticipated that the Shetland pony would recover some of his lost inches when taken to the south of England—to the area containing the remains of the 12-to 13-hands wild races from which small British breeds have mainly sprung. There is, however, no longer any doubt that the small size is, as a rule, maintained however favourable the surroundings. Why the Sheltie fails to respond to the growth stimuli which favourable surroundings so abundantly provide it is extremely difficult to explain. In the language of the day, one can only say that the limbs have forgotten how to grow beyond a certain size, and add that this loss of “memory” may be the result of breeding from the smallest individuals regardless of their consanguinity. In 1892 Mr Christopher Wilson, in a letter to Mr Meiklejohn, then in charge of the Bressay Stud, said: “With regard to the Shetland ponies, your great object is to keep them small.... There is no class of animal to which inbreeding can be better applied, as all you will lose by inbreeding is size, which is what you want.... To inbreed them there is only one plan. Select your very best stallion and put him to a certain number of mares, and then put all the good fillies when three years old to their father; also, select your very best mare and put her to another stallion, and go on breeding from her to the same stallion until you have a colt, then put that colt to his mother, and use the produce to breed from with the produce obtained by putting the fillies above mentioned to their father.” A better plan for fixing the size could hardly be imagined. If followed for some years the size of the bones and muscles would doubtless be so effectively stereotyped that, however much their “memory” was jogged by “fresh fields and pastures new,” there would be little or no response. Although close in-and-in breeding was undoubtedly practised, the Shetland Pony Stud-Book indicates that the advice of the originator of the “Sir George” strain of hackney ponies was not literally followed.

The Ancestors of the Shetland Pony.—From pigmy horses it seems but a step to the little “fossil” horses of bygone days. It is hence not surprising that many are led to inquire to which particular branch of the equine family tree the Shetland pony belongs.

Not many years ago it was said the horse tribe was at the start represented by a primitive race about the size of a fox but with as many hoofs as a tapir—four in front and three behind,—that in course of time a new race arose (with three hoofs in front as well as behind) which eventually gave rise to the one-toed ancestor of all the living Equidæ.

Now, however, we know that in Eocene times there were several kinds or species of four-toed “horses” from which were derived, in the Oligocene and Miocene periods, numerous three-toed species, some of them doomed to early extinction, others to bring forth one-toed races which in due time produced the ancestors of the modern horses, asses, and zebras.

Hence it is now admitted that, in the past as in the present, the horse tribe was always represented by several species, not a few of which at times occupied the same area. It is also now admitted that the modern domestic breeds include several wild prehistoric species among their ancestors.