Study of... an otter

Want to know exactly what makes this creature so special? Abigail Whyte offers up a Bluffer’s Guide to the otter

With its long, streamlined body, webbed toes and waterproof fur, there's no denying the otter is the ultimate river mammal. It’s also the ultimate comeback kid. Forty years ago the otter was pushed to the very brink of extinction by a mixture of hunting and toxic pesticide-laced waterways but over the decades there has been a nationwide clean up of our rivers and otter numbers are at a healthy level once again. Levels are rising so much that, despite being largely shy, nocturnal creatures, daylight sightings of otters are on the increase, and they're even being spotted making themselves at home in towns and cities. Words: Abigail Whyte

Otters thrive in clean lakes, streams, rivers, canals, coastal areas and offshore islands. Otters are an indicator species – because they're at the top of the food chain, they give a good picture of how healthy the general waterway environment and fish stock levels are.

Despite being shy and timid in the presence of humans, otters are also inquisitive, intelligent and playful creatures that enjoy a good frolic in the water, a wrestle with their cubs and sliding along muddy banks.

There is no set breeding season – a bitch can give birth to a litter of two to four cubs at any time of year. The cubs stay with their parents learning diving and hunting skills until they're 8 to 12 months old. The male parent then goes off to live on his own, characteristic of the otter's solitary nature.

Otters grow up to a metre long including its thick tapering tail, which is about 20 inches long. It has a broad, flattened, dog-like face and powerful jaws for crunching into crustaceans. Its streamlined body, waterproof fur and webbed feet make it an effective aquatic hunter.

As they dive they arch their tail above the water's surface and close their eyes and ears as they submerge. It swims mainly with its hind legs and tail, using its forelegs for steering and balance, propelling its body expertly like a seal. If you see an otter dive under water, follow the trail of bubbles on the surface and wait for it to re-emerge for air.

Otters have chocolate-brown fur with a pale underside. The fur doesn't become waterproof until the otter is around three months old. When submerged bubbles of air trapped in the fur give it a silvery appearance.

Despite having five toes the otter leaves asymmetric four-toed tracks in the sand or mud. Mink prints are a lot smaller.

Otters eat eels, salmon, trout, crayfish, frogs, water fowl and small mammals. They've even been spotted eating rats and rummaging through bins in urban environments.

The best way to track the elusive otter is to spot their droppings, or spraints, which they deposit in sheltered areas to avoid them being destroyed by the elements. They are a marker of its territory; a 'keep-out' sign to other otters. Spraints have a characteristic scent – a mixture of freshly mown hay and fish – and usually contain fish bones and scales. 


Last date edited: 6 January 2015

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