competition with the native productions. Under these circumstances, if our
domesticated animals did not undergo change of some kind, the result would be
quite opposed to the conclusions arrived at in this work. Nevertheless, I do
not doubt that the simple fact of animals and plants becoming feral, does
cause some tendency to reversion to the primitive state; though this tendency
has been much exaggerated by some authors.

[I will briefly run through the recorded cases. With neither horses nor cattle
is the primitive stock known; and it has been shown in former chapters that
they have assumed different colours in different countries. Thus the horses
which have run wild in South America are generally brownish-bay, and in the
East dun-coloured; their heads have become larger and coarser, and this may be
due to reversion. No careful description has been given of the feral goat.
Dogs which have run wild in various countries have hardly anywhere assumed a
uniform character; but they are probably descended from several domestic
races, and aboriginally from several distinct species. Feral cats, both in
Europe and La Plata, are regularly striped; in some cases they have grown to
an unusually large size, but do not differ from the domestic animal in any
other character. When variously-coloured tame rabbits are turned out in
Europe, they generally reacquire the colouring of the wild animal; there can
be no doubt that this does really occur, but we should remember that oddly-
coloured and conspicuous animals would suffer much from beasts of prey and
from being easily shot; this at least was the opinion of a gentleman who tried
to stock his woods with a nearly white variety; if thus destroyed, they would
be supplanted by, instead of being transformed into, the common rabbit. We
have seen that the feral rabbits of Jamaica, and especially of Porto Santo,
have assumed new colours and other new characters. The best known case of
reversion, and that on which the widely spread belief in its universality
apparently rests, is that of pigs. These animals have run wild in the West
Indies, South America, and the Falkland Islands, and have everywhere acquired