About the time of sunset the Otter wakes up, utters his flute-like whistle, enters the water, and hunts favourite pools in the stream for fish, which it secures by diving below them. These are always brought to the bank to be consumed. The backbone is first bitten through behind the gills; and where fish are large (salmon) and plentiful the Otter often contents himself with a mouthful from the shoulder. At other times he may eat methodically from this point to the tail, which is always left. Apart from the fact that he has to make frequent visits to the surface in order to breathe, he is as much at home in the water as a fish, swimming in circles where the water is deep, and his movements in that element are as graceful as those of the fishes he pursues. Not that his diet is restricted to fish: he is very fond of the river crayfish, and will turn over every stone in his section of the stream in his search for them. He is known also to consume frogs, which he carefully skins before eating them. Occasionally he indulges in wild duck or moorhen; and when he hunts on shore may catch a rabbit unawares, a rat or a vole. When he goes down stream he floats with the current his forelegs pressed against his sides and only the upper part of his head with eyes, ears, and nostrils exposed. [Illustration: _Pl. 40._ _E 60._ *Pine Marten.* Mustela martes.] [Illustration: _Pl. 41._ _E 61._ *Stoat or Ermine.* Mustela ermina.] In summer when the water is low in the streams, he travels across country from pool to pool by night, seeking some estuary or the open coast. Although so obviously adapted for an aquatic life, the Otter can travel with speed on land, and it has been estimated that in one night it will cover about fifteen miles. On arrival at the coast it will seek some bat-haunted cave that has been favoured by its kind for generations, and will work the shallow waters for flat fish, bass, crabs, and mussels. From here also it will make excursions over a considerable area of neighbouring country by means of the creeks and marshes. In autumn it will return to its favourite stream and feed royally on migrating eels that are on their way to the sea. It does not hibernate. In winter when fishing may be poor, it may be constrained to dig out the mole and the vole from their underground retreats to provide a meal, and is even glad of hibernating insects, either in the larval or pupal condition. It also shows a fondness for the freshwater mussel (_Anodonta cygnea_). [Illustration: *Skeleton of the Otter.*]