Otter territorial behaviour through sprainting (marking with scent deposits) provides insights into population health and habitat quality across UK river systems.
Otters in high-density areas experience increased territorial conflict, with encounters between males causing injury. Otters in degraded river habitats with poor fish availability show reduced spraint density indicating lower territorial stability and nutritional stress. River improvement that improves fish populations and bankside habitat directly improves otter welfare through reduced competition and better nutrition.