Capra hircus, Ovis steatopyga_).[9] In all such cases we are not concerned
with sexual inversion, but merely with the accidental turning of the
sexual instinct into an abnormal channel, the instinct being called out
by an approximate substitute, or even by diffused emotional excitement, in
the absence of the normal object.

It is probable, however, that cases of true sexual inversion--in which
gratification is preferably sought in the same sex--may be found among
animals, although observations have rarely been made or recorded. It has
been found by Muccioli, an Italian authority on pigeons, that among
Belgian carrier-pigeons inverted practices may occur, even in the presence
of many of the other sex.[10] This seems to be true inversion, though we
are not told whether these birds were also attracted toward the opposite
sex. The birds of this family appear to be specially liable to sexual
perversion. Thus M.J. Bailly-Maitre, a breeder of great knowledge and a
keen observer, wrote to Girard that "they are strange creatures in their
manners and customs and are apt to elude the most persistent observer. No
animal is more depraved. Mating between males, and still more frequently
between females, often occurs at an early age: up to the second year. I
have had several pairs of pigeons formed by subjects of the same sex who
for many months behaved as if the mating were natural. In some cases this
had taken place among young birds of the same nest, who acted like real
mates, though both subjects were males. In order to mate them productively
we have had to separate them and shut each of them up for some days with a
female."[11] In the Berlin Zoölogical Gardens also, it has been noticed
that two birds of the same sex will occasionally become attached to each
other and remain so in spite of repeated advances from individuals of
opposite sex. This occurred, for instance, in the case of two males of the
Egyptian goose who were thus to all appearance paired, and always kept
together, vigorously driving away any female that approached. Similarly a