Darwin says: "A horse is trained to certain paces, and the colt inherits
similar consensual movements."[39] But selection of the constitutional
tendency to these paces, and imitation of the mother by the colt, may
have been the real causes. The evidence, to be satisfactory, should show
that such influences were excluded. Men acquire proficiency in swimming,
waltzing, walking, smoking, languages, handicrafts, religious beliefs,
&c., but the children only appear to inherit the innate abilities or
constitutional proclivities of their parents. Even the songs of birds,
including their call-notes, are no more inherited than is language by
man (_Descent of Man_, p. 86). They are learned from the parent.
Nestlings which acquire the song of a distinct species, "teach and
transmit their new song to their offspring." If use-inheritance has not
fixed the song of birds, why should we suppose that in a single
generation it has transmitted a newly-taught method of walking or
trotting?
It is alleged that dogs inherit the intelligence acquired by association
with man, and that retrievers inherit the effects of their
training.[40] But selection and imitation are so potent that the
additional hypothesis of use-inheritance seems perfectly superfluous.
Where intelligence is not highly valued and carefully promoted by
selection, the intelligence derivable from association with man does
_not_ appear to be inherited. Lap-dogs, for instance, are often
remarkably stupid.
Darwin also instances the inheritance of dexterity in seal-catching as a
case of use-inheritance.[41] But this is amply explained by the ordinary
law of heredity. All that is needed is that the son shall inherit the
suitable faculties which the father inherited before him.