I will add to Ian's comment that very small horses have, since the
Pleistocene, occurred in the British Isles -- I've mentioned this before
in this list -- an example of Heaney's Law or the island size-body mass
relationship for mammals in the northern hemisphere. An 81-cm Shetland is
not beyond the pale, and neither is a donkey that small.

As to actually breeding horses for very small or 'miniature' size: I would
certainly like to see evidence for this practice at any time in the past.
Throughout history people everywhere who kept horses seem to have been
trying to increase their size rather than diminish it. In Spanish, the
word for a very small horse is 'petizo', which has a somewhat pejorative
connotation of 'scrubby'. Even the term 'pony' in English, though it did
not have this meaning originally, has at times, and in some circles, taken
on a negative connotation (vis., see the OED comments about Lady Brassey
and 'polo ponies').

The recent fad for miniature horse breeding began with a mutation that
released the gene complex that produces midgets (i.e. small stature that
is endocrine-driven, as opposed to achondroplasia); it occurred in a male
horse bred on an Argentinian ranch owned by the Falabella family. As the
little stallion had otherwise good conformation, the family decided to
permit it to breed, and selected for his cover a remuda of good mares.
From this policy they developed a herd of well-conformed but very small
horses. This was in the 1940's. For many years, they absolutely refused to
sell or permit off their property any of their small horses, but
eventually the last heiress of that family did permit some sales, which of
course brought in fabulous amounts of money. A very few of today's
registered miniature horses do go back to Falabella bloodlines; most have,
however, been bred from an achondroplast gene complex.

Shetland and other small 'natural' ponies have commonly been used as
broodmares in miniature horse breeding programs after they began in the
U.S., as have a smaller number of Arabians selected likewise for small
stature. Because dwarfing genes are now so prevalent among the 'miniature'
population, we see not only the usual birthing difficulties -- most
miniature horses must be brought into this world via C-section because the
heads are too big to go through the dam's birth canal -- but also the
whole array of developmental and physiolgical problems associated with
achondroplasty and related genetic syndromes. Some of these are so severe
as to make the animal nonviable at least for breeding, and thus are
self-limiting; but most miniatures in my experience could hardly be called
'problem free'.

And this is my point toward any argument for deliberately-bred 'miniature'
horse bones in any ancient deposit: You should expect to see signs of
achondroplasty, as this mutation is apparently far more common in horses
than the thyroid/hypothalamic midget. Where signs of achondroplasty are
not evident, yet the bones are small; and especially if you are in the
British Isles -- you will have to show why the bones are not those from
ponies of the offshore islands, or else small donkeys. With Vera
Eisenmann's help (I say this tongue in cheek) -- you might be able to do
it! Or how thick is your caliper callus! -- Cheers -- Deb Bennett

> Dear Jessica,
>
> What you need to do is compare it with the modern data in the following
> paper by the log ratio method:
>
>
> Eisenmann, V. and Beckouche, S. 1986, Identification and  discrimination
> of
> metapodials from Pleistocene and modern Equus, wild and domestic, in
> Meadow,
> R.H. and Uerpmann, H-P. (eds.) Equids in  the Ancient World Vol. I, pp.
> 117-63,
> Beheifte zum Tübinger Atlas des  Vorderen Orients, Reihe A 19/1,
> Wiesbaden:
> Dr. Ludwig Reichart  Verlag.
> A downloadable version can be  found at: _www.vera-eisenmann.com_
> (http://www.vera-eisenmann.com)
> Best wishes,
> Ian
>