Brandt’s and Whiskered bats were only separated as distinct species in 1970 and identification is still problematic. The main visible distinguishing feature is the teeth, with the Brandt’s Bat having a clear cusp on the upper premolar. A secondary distinguishing feature for males is that the penis is bulbous-shaped compared to the straight-sided Whiskered Bat penis. Echolocation calls are very similar. As a result of identification difficulties the number of confirmed records of both species is small, with most bats being recorded as Whiskered / Brandt’s. Recently it has become possible to obtain an identification to species level by carrying out DNA tests on bat droppings collected from roosts. The distribution map shows an even, but very thin spread of Brandt’s bat records across North Yorkshire. Bat detectors used during surveys frequently detect Whiskered / Brandt’s bats, though usually in small numbers.