ourselves, we may see in business, where the better equipped species,
that is to say, the big capitalist, flourishes, while the less well
equipped species, the small capitalist, succumbs. Mr. Chalmers Mitchell,
Secretary of the London Zoological Society and familiar with the habits
of animals, has lately emphasised the contention of Darwin and shown
that even the most widely current notions of the extermination of one
species by another have no foundation in fact.[1] Thus the thylacine or
Tasmanian wolf, the fiercest of the marsupials, has been entirely driven
out of Australia and its place taken by a later and higher animal, of
the dog family, the dingo. But there is not the slightest reason to
believe that the dingo ever made war on the thylacine. If there was any
struggle at all it was a common struggle against the environment, in
which the dingo, by superior intelligence in finding food and rearing
young, and by greater resisting power to climate and disease, was able
to succeed where the thylacine failed. Again, the supposed war of
extermination waged in Europe by the brown rat against the black rat is
(as Chalmers Mitchell points out) pure fiction. In England, where this
war is said to have been ferociously waged, both rats exist and
flourish, and under conditions which do not usually even bring them into
competition with each other. The black rat (_Mus rattus_) is smaller
than the other, but more active and a better climber; he is the rat of
the barn and the granary. The brown or Norway rat (_Mus decumanus_) is
larger but less active, a burrower rather than a climber, and though
both rats are omnivorous the brown rat is more especially a scavenger;
he is the rat of sewers and drains. The black rat came to Northern
Europe first--both of them probably being Asiatic animals--and has no
doubt been to some extent replaced by the brown rat, who has been
specially favoured by the modern extension of drains and sewers, which
exactly suit his peculiar tastes. But each flourishes in his own
environment; neither of them is adapted to the other's environment;