Lithe swimmers and excellent hunters, otters are surprisingly common, but hard to spot. Over recent years, dedicated conservation efforts have helped ensure the long-term survival of this shy mammal.
Did you know groups of otters are called a 'romp', 'lodge', 'family' or 'bevy'?
Otter facts
Scientific name: Lutra lutra
Family: Mustelidae
Diet: Fish, amphibians, birds, eggs, and insects
Size: 60-80cm with a 32-56cm tail
Weight: 6-8kg
Lifespan: 5-10 years
About otters
There are 13 different otter species worldwide, but the Eurasian (or European) otter is the only species to inhabit the UK. One of our top predators, these elusive mammals are lithe swimmers, as suited to life in the water as on land and underground.
The UK population is showing healthy signs of growth after its sad decline in the 1950s. Otters are now found in most of England and Wales as conservation efforts successfully encourage their return. They are also found in coastal habitats, particularly in Scotland.
Otters and our canals
Otters are top predators in the UK. The largest threat to their survival is loss of habitat, road traffic accidents, and pollution. They require clean waters, with abundant food sources and plenty of vegetation to burrow. Our canals provide safe and connected habitats for otters to live and breed.
Otters are large, powerful mammals with brown fur along slender bodies, short legs, and pale undersides. Males tend to be larger than females. They have a broad snout with small ears and eyes near the top of the head, enabling them to see while underwater.
They're built to swim with long, muscular tails and webbed feet, while sensitive whiskers and claws empower them to hunt and catch prey.
An otter with brown fur, long whiskers, small ears, and eyes high on the head swims, mostly submerged in water.
What do otters eat?
Otters are capable of catching prey equal to their own body weight and can eat up to a kilogram of food each day. Excellent hunters underwater, otters mostly eat fish, shellfish, and amphibians. Otters are strong swimmers but cannot hold their breath for long and dive for less than 30 seconds.
They also eat water birds, like moorhens and coots, insects, eggs and small mammals.
How do otters breed?
Although largely solitary animals, otters come together to breed. They mate year-round, but most cubs (or pups) are born between May and August after nine weeks gestation. There are normally two to three blind cubs in a litter, each with short, grey fur.
Female otters raise their cubs without help from the male. They emerge from the holt (their underground den) after about three months but still rely on their mother for food and stay with her for about a year. The pups can communicate with their mother by making whistling and murmuring noises.
Where do otters live?
Though rare, otters are widespread, particularly in Wales and the southwest of England. They like clean lakes, rivers, and canals – living wherever there is fresh water, food and secluded, overgrown vegetation.
Otter territories are vast, covering up to 40km of watercourses and dense vegetation or wooded areas, which they use for resting purposes and breeding 'holts' (their homes). These nests are usually in natural cavities, like river or canal banks. They have several chambers connected by tunnels and multiple entrances, some of which might be underwater.
Recent conservation success has meant the return of otters to almost every counties of England. We've also seen a rise in populations on our urban canals, a good indication of improving biodiversity. We work with our volunteers to look for otter spraints and track populations over the years.
They might be found across the UK, but otters are timid and not often observed by humans. You're more likely to come across one of their smaller and more confident cousins, the mink.
It's far easier to see signs of an otter than the elusive animal themselves.
Look for five-toed footprints, droppings, or 'spraints' along our canal banks. Otters leave these scented messages by fallen trees, weirs, and bridges to signal mates and defend their territory. Spraints contain fish bones and often have a distinctive, sweet but fishy smell – sometimes reminiscent of jasmine.
Otters rely on their dense, water-resistant fur to insulate them when submerged.
What's the best time of day to spot otters?
Otters are most active at night, dawn, and dusk, and rarely seen during the day.
You might spot an otter in the canal from a distance, leaving a V-shaped ripple in their wake as they swim. Their head and back are barely visible in the water, but you may see a glimpse of their tail and a stream of bubbles as they dive for food.
What's the difference between an otter and a mink?
Our native otters (pictured right) and non-native American mink (pictured left) are both found on our canals and often confused.
However, they're easy to tell apart. Otters are much bigger than the invasive mink species, with lighter brown fur and a broad, flat head. Minks have a more ferret-like appearance, with a pointed muzzle.
Threats to otters
In the UK, the European otter neared extinction in the 1950s and 60s, with pesticides affecting their breeding. However, changes in farming practices, legal protection, and improvements to habitats mean populations are more stable today. They're a protected species, and it's illegal to disturb them.
