Given that there is a living to be made at night, and given that alternative daytime trades are thoroughly occupied, natural selection has favoured bats that make a go of the night-hunting trade.

考虑到夜晚也可以生存，并且可供选择的白天的“交易”完全被占用，它们自然选择偏爱那些成功在夜间进行捕食“交易”的蝙蝠。