Gut bacteria have beneficial effects, such as the ability to break down foods which would otherwise remain indigestible. If birds and bats have reduced gut micr

Gut bacteria have beneficial effects, such as the ability to break down foods which would otherwise remain indigestible. If birds and bats have reduced gut microbiomes then it suggests they have a reduced ability to digest certain foodstuffs. Also: the weight loss referred to is the reduction in gut bacteria mass.