they are only formable. Accordingly he is not quite able to take
care of himself; he must for a time be watched and nursed. All
mammals and most birds have thus a period of babyhood that is not
very long, but is on the whole longest with the most intelligent
creatures. It is especially long with the higher monkeys, and
among the man-like apes it becomes so long as to be strikingly
suggestive. An infant orang-outang, captured by Mr. Wallace, was
still a helpless baby at the age of three months, unable to feed
itself, to walk without aid, or to grasp objects with precision.

But this period of helplessness has to be viewed under another
aspect. It is a period of plasticity. The creature's career is no
longer exclusively determined by heredity. There is a period after
birth when its character can be slightly modified by what happens
to it after birth, that is, by its experience as an individual. It
becomes educable. It is no longer necessary for each generation to
be exactly like that which has preceded. A door is opened through
which the capacity for progress can enter. Horses and dogs, bears
and elephants, parrots and monkeys, are all teachable to some
extent, and we have even heard of a learned pig. Of learned asses
there has been no lack in the world.

But this educability of the higher mammals and birds is after all
quite limited. By the beginnings of infancy the door for
progressiveness was set ajar, but it was not all at once thrown
wide open. Conservatism stilt continued in fashion. One
generation of cattle is much like another. It would be easy for
foxes to learn to climb frees, and many a fox might have saved his
life by doing so; yet quickwitted as he is, this obvious device
never seems to have occurred to Reynard. Among slightly teachable