Okay, there's a really cool reason for these groupings, based on evolution.
First, the "oh hi doggies" are almost invariably fruit or nectar eaters, relying on eyesight & smell to locate non-moving food. No sonar.
To the insect-eaters: there are two ways to emit 'sonar' pulses: nose or mouth.
Contrary to popular belief, there are only four kinds of bats.
