The European otter, a semi-aquatic carnivore, is native to rivers, lakes, and coastal habitats across the UK. Recognisable by its sleek brown fur, webbed feet, and powerful tail, it is an apex predator feeding on fish, crustaceans, and amphibians. Once severely reduced due to pollution and habitat loss, otter populations have rebounded in recent decades, making them an indicator of healthy freshwater ecosystems.