The Making of Species 
Plains, D. Dewar records an instance of a num- 
ber of crows killing in revenge so powerful a 
bird as the kite. 
Since very many species seem to throw off 
melanistic variations, it may perhaps be asked, 
How is it that more black species do not exist ? 
The reply is twofold. In the first place, it is 
quite likely that in some organisms black varia- 
tions are not correlated with courage or extreme 
pugnacity, and when such is the case the melan- 
istic varieties will be more likely to be exter- 
minated by foes, on account of their conspicuous- 
ness. It must be remembered that, other things 
being equal, the inconspicuously coloured organ- 
ism has a better chance of survival than the 
showily coloured one. This is, of course, a very 
different attitude from that which insists on the 
all-importance to animals of protective coloura- 
tion. Secondly, it is not difficult to see how too 
much courage may be fatal to an animal in lead- 
ing it to take risks which a more timid creature 
would refrain from doing. This, as we have 
already suggested, is probably the reason why 
the black panther is so scarce. The black colour 
is readily inherited, so there must be some cause 
which tends to kill off the black varieties of the 
panther. 
Lest it be thought the idea that excessive 
courage and pugnacity are harmful is mere fancy, 
let us quote from the account of the nesting 
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