The
internal skeleton gave fewer advantages at the start; its greatest
superiority had lain in future possibilities.
But which vertebrate is heir to the future? It would have been a
hard choice between reptile and bird. I feel sure that I, for one,
should not have selected the mammal, a small, feeble being, hiding
in holes and ledges, and continually hard put to it to escape
becoming a mouthful for some huge reptile. And yet the persecution,
the impossibility of contending by brute strength, may have forced
the mammal into the line of brain-building and placental
development. The early development of mammals appears to have been
slow. Palaeontology proves that they were long surpassed by reptiles
and birds. But the little mammal had the future. The battle was to
go against the strong.
Once again. The arboreal life of higher mammals would seem to be
most easily explained by the view that they were driven to it by
stronger carnivorous mammals having possession of the ground. Brain
was good, for it planned escape from enemies. But it did not give
its possessor immediate victory over muscle, tooth, and claw in the
tiger. That was to come far later with the invention of traps and
guns. Brain gave its possessor a sure hold of the future, and just
enough of the present to enable it to survive by a hard struggle.
Pages:
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259