But now the annual slaughter, begun in 1967 after a local boy was bitten by an Eastern Diamondback rattlesnake (he survived), is to become “a humane event that celebrates these great native animals”. Snakes are to be borrowed from zoos, instead of hunted down, and, say organisers, the celebration will focus on “educating people about wildlife” and conserving it.
One reason for the change of heart is that the snakes have become increasingly rare, through losing their habitat, getting run over – and being rounded up for the festivals. So great has been the threat from hunting that non-rattling rattlers have been evolving, because they are less likely to be noticed.
Non-rattling rattlers existed before the festival, before the slaughter. So they have not evolved in response to said festival.
There might though be more of them as a portion of the local rattler population, this is true. But this is not evolution, this is selection. The winnowing of evolved forms through the various pressures upon such evolved forms.
The festival has not changed evolution, it has changed the pressures of natural selection.