A dense mass of bats high within a passageway in Carlsbad Cavern shows up as a bright, irregular swath on the ceiling when a thermal imaging camera pans along the roost. Plenty of bats are dropping off the ceiling for a little turn around the cave before flying back up to roost.

Found in "Carlsbad's 8 million 'lost' bats likely never existed" at sciencenews.org/view/generic/id/40178/title/Carlsbads_8_million_lost_bats_likely_never_existed

Video Credit: Nickolay Hristov and Louise Allen