r parent-stock, is chiefly founded, as
far as I can discover, on feral pigs. But even in this case the belief is
not grounded on sufficient evidence; for the two main types of _S. scrofa_
and _Indica_ have never been distinguished in a feral state. The young, as
we have just seen, reacquire their longitudinal stripes, and the boars
invariably reassume their tusks. They revert also in the general shape of
their bodies, and in the length of their legs and muzzles, to the state of
the wild animal, as might have been expected from the amount of exercise
which they are compelled to take in search of food. In Jamaica the feral
pigs do not acquire the full size of the European wild boar, "never
attaining a greater height than 20 inches at the shoulder." In various
countries they reassume their original bristly covering, but in different
{78} degrees, dependent on the climate; thus, according to Roulin, the
semi-feral pigs in the hot valleys of New Granada are very scantily
clothed; whereas, on the Paramos, at the height of 7000 to 8000 feet, they
acquire a thick covering of wool lying under the bristles, like that on the
truly wild pigs of France. These pigs on the Paramos are small and stunted.
The wild boar of India is said to have the bristles at the end of its tail
arranged like the plumes of an arrow, whilst the European boar has a simple
tuft; and it is a curious fact that many, but not all, of the feral pigs in
Jamaica, derived from a Spanish stock, have a plumed tail.[172] With
respect to colour, feral pigs generally revert to that of the wild boar;
but in certain parts of S. America, as we have seen, some of the semi-feral
pigs have a curious white band across their stomachs; and in certain other
hot places the pigs are red, and this colour has likewise occasionally been
observed in the feral pigs of Jamaica. From these several facts we see that
with pigs when feral there is a strong tendency to revert to the wild type;
but that this tendency is largely governed by the nature of the climate,
amount of exercise, and other causes of change to which they have been
subjected.

The last point worth notice is that we have unusually good evidence of
breeds of pigs now keeping perfectly true, which have been formed by the
crossing of several distinct breeds. The Improved Essex pigs, for instance,
breed very true; but there is no doubt that they largely owe their present
excellent qualities to crosses originally made by Lord Wes