ONE-OFF BEASTS

The only mammal which can truly fly is the bat - other 'flying' mammals merely propel themselves by gliding downwards.

The only mammals which are blind are Indian river dolphins which live in such muddy water that their capacity for sight has undeveloped.

The only mammal which sleeps underwater is the sitatunga, an antelope which lives in marshland and sleeps for safety in shallow pools with just its nose sticking out for air.

Source: various