Spraints are typically identified by smell and are known for their distinct aromas, the smell of which has been described as ranging from freshly mown hay to putrefied fish. The European otter's spraints are black and slimy, 3–10 cm (1–4 in) long and deposited in groups of up to four in prominent locations near water. They contain scales, shells and bones of water creatures. Because of the decline of otters in Britain, several surveys have been made to record the distribution of the animal, usually by recording the presence of spraint.  Further, there is some evidence that spraint density is correlated with otter density.