Queen bats were large, hairy bat-like creatures that lived in the caves of Androzani Minor.
Biology
They had a three year life cycle, some of which was spent in a chrysalis. These chrysalises had a large supply of unrefined spectrox, which was refined and used by the humans of Androzani Major. (TV: The Caves of Androzani)
History
The bats were killed or driven out by the mining androids, which caused them to move into the airless caves deep underground to die. The [Fifth Doctor] had to climb down the caves to the deep levels in desperation to obtain Bat milk witch was a cure for him self and (Peri) who had contracting [spectrox] poisoning. Sadly the Doctor only managed to milk enough for Peri