All Mouse-sized micro-Bats use ultrasound calls for echolocation, but fruit bats and flying foxes (megabats) have lost this ability. Although we can’t hear it, echolocation requires bats to scream at 130 decibels! That takes a lot of energy, but the micro-Bats can harness some of their wingbeats’ muscular efforts to generate the air pressures needed for their ultrasound calls. Mega Bats flap their wings too slowly for this to work and considering that flying is already more tiring for them because they are heavier, it makes echolocation too exhausting to be worth it.
