The purposes of this study were to ascertain the food habits of the Eurasian otter Lutra lutra L., in two types of riparian habitats. The study was conducted along a forest stream (Ungok Stream in Gyeongsangbuk-do, central-eastern part of South Korea) and a larger river (Seomjin River in Jeollanam-do, south-western part of South Korea). A total of 4268 spraints (faeces of otters) were analyzed for investigation of otter prey items. In the forest stream, fish were the primary prey items throughout the year (relative frequency of occurrence, RFO 64.74%), and other prey items included amphibians (17.37%), insects (8.82%), birds (4.74%), crayfish (0.57%), and mammals (0.54%). However, the RFO of fish (82.58%) was strikingly higher and the composition of amphibians (1.79%) was lower in the larger river system. The obtained information on food habits from different types of rivers will be helpful for the management of the endangered Eurasian otters, especially in forested countries.

Published online 26 October, 2023; Print publication 31 January, 2024