European otter
Lutra lutra
This mammal was almost driven to extinction in Britain by the 1970s, but efforts to restore rivers and protect the species ensured its survival.
How it shapes the landscape
Otters are near the top of the aquatic food chain. Known for their playful nature, they’re a delight to watch and humans have long enjoyed observing them in their natural habitats. Their play demonstrates how they’re skilled and agile predators. They’re well-adapted fish hunters, with webbed feet, spacious lungs and a streamlined body for moving quickly underwater. Their presence in a freshwater habitat alters prey (fish) behaviour and keeps fish population sizes in check.
Otters are members of the mustelid family and are related to weasels, badgers and pine martens. There are 13 otter species worldwide, but the European otter is the only species that can be found in Britain.
DID YOU KNOW?
Recent studies suggest that otters can smell underwater – a helpful skill when searching for food in rivers and lakes.
Where it likes to be
Otters are semi-aquatic mammals – they hunt, feed and mate in water, but shelter, sleep and birth on land. They need a large, unpolluted body of fresh water with plentiful fish to support their active lifestyle. In Europe and Asia, they tend to live in the same habitats as beavers. Otters sometimes even use abandoned beaver lodges as a ‘holt’ (a term used to describe their dens).
Because otters primarily live beside and in rivers, they’re often vulnerable to human activity across an entire catchment. They prefer a mix of habitats – including scrub, woodland, marshy areas and elevated ‘islands’ in waterways. Large, established trees along water edges with strong root systems are ideal holts. Otters appear to favour ash and sycamore trees the most.
How much space they need
European otters prefer a mostly solitary life but can be found in small groups of up to six individuals. They come together during the mating season and stay together for a short time after their pups are born. Britain’s native otters are strongly territorial, which means they defend their domain and avoid sharing it with other otters of the same sex. Individual territories can vary in size from 1 – 40km, depending on how much food and space is available.
As otters are a river species, the size of the river is the most important factor that determines if an otter will inhabit a specific area. Otters can also live along the coastline, but still require access to a large body of freshwater to thrive.
Background story
Otters have long been hunted in Britain. However, their rapid decline in the 20th century was mostly due to the pollution of waterways with harmful pesticides and rapid habitat loss caused by changes in land management.
Hunting was finally made illegal in the 1970s after a rapid decline in numbers caused by pollution. Thanks to the increased regulation of pesticides, including a ban on the most harmful, British waterways have since returned to better health — and as a result, otter numbers have gradually increased, and by 2011 had returned to every county in Britain.
Can we have them in Britain?
Absolutely! Otters may already be back in Britain, but it’s vital that we continue to support this species’ recovery by improving river health and providing suitable habitats as they gradually re-establish themselves.
Otters are one of Britain’s greatest conservation success stories. Their return demonstrates that it is possible to work together to halt and reverse the decline of a species, and that we can indeed learn to coexist with a predator after a period of absence.
In summary
- Primarily eats fish – when food is scarce, it also feeds on crustaceans, amphibians and birds.
- An otter den or ‘holt’ is typically located near water sources, such as rivers and lakes.
- Mostly active at dusk and after dark – so, if you want to see them, your best chance is to take a stroll at sunset.
- The return of otters to Britain is a step forward, but supporting their recovery requires ongoing work to restore the health of river habitats.
- The Wildlife Trusts. (n.d.). European otter.
- UK Wild Otter Trust. (2024). Eurasian otter 101.
- Wildfowl and Wetlands Trust. (n.d.). Spotlight on: the European otter (and how to see them in the wild).
- BBC Countryfile (2022). Guide to Britain's otters: history, characteristics and where to see them.
- Natural England. (2007). Otter: European protected species, Natural England Species Information Note SIN006.
- Chanin P. (2003). Ecology of the European Otter. Conserving Natura 2000 Rivers Ecology Series No. 10. English Nature, Peterborough.
