In many countries the Eurasian otter (Lutra lutra) is extinct or numbers are declining; resulting in a classification as “near threatened” on the IUCN’s Red List. In one-third of the European countries, however, conservation efforts, enabled the return of the species or the improvement of weakened populations. …

To protect the otter population in the Netherlands, it is important to understand the otter's ecology. Otters have a very high metabolic rate, and they need to eat often. Here for we need to know of what species their diet consists, as this might influence their behaviour and distribution. When we know …