The invertebrate fauna is best known from studies conducted over many years at the Moor House NNR. The area shares many characteristics with the Cairngorms region of Scotland but there are some notable rarities, including a rove beetle, Olophrum assimile, which is known from only one other locality in Britain, a carabid beetle, Nebria nivalis, which has not been found anywhere else in the North Pennines and is known elsewhere in Britain only from North Wales, the Cairngorms and Scafell Pike, and a leiodid beetle, Hydnobius spinipes, which is known from only four other localities in Britain. In all, some 27 endangered species and over 70 nationally scarce species have been recorded from the Moor House reserve.