By Isabel Johnson, work experience student

I am currently doing my AS levels at sixth form and have come to the Wiltshire Wildlife Trust for a week of work experience with the Water Team. It has taken me a while to decide what direction I want to next go in: choosing three A level subjects was easy enough, but deciding how to specialise further is more difficult. After many meetings with the school’s career advisor and (exhausting!) discussions around the dinner table with my parents, I have decided that the environment (particularly the marine side of things and the hazards it can pose, for example, flooding if the rivers are not managed properly) is something that I would like to study and this is why I have ended up working with the Water Team here! This month’s blog is about otters, as I wanted to further my research into them.

There is only one species of otter found in the UK: the Eurasian otter. This mammal has inhabited our freshwaters since the last Ice Age, living off a diet of all kinds of fish and inhabiting near to bankside vegetation with secluded sites for their dens (holts). Physically, otters have short, brown fur with white underparts, short legs with webbed feet, a tapering tail, a small head with a blunt muzzle and very long whiskers, making up their long, streamlined figure. Their ears and nostrils are high on the otter’s head to allow them to see and breathe whilst submerged in the water. They are well adapted to living and hunting in the water; it has been recorded that they can swim at up to 12km/h.

c_Darin_SmithImage 1: Otters have long, streamlined bodies making them fast swimmers. They can also out run man on land too! Photo © Darin Smith

Despite their large size (up to 12kg!), this animal is difficult to spot. The first reason for this is due to the otter’s secretive, agile and nocturnal nature. The second reason is due to human impacts on them and their habitats; something that resulted in the mass decline of the Eurasian Otter in the 1950s, giving the species the classification of ‘endangered’. This was primarily due to:

  • Pollution of rivers (e.g. through the introduction of particular pesticides used in agriculture which resulted in wide-scale mortalities);
  • Habitat loss (e.g. the building of new roads, disturbing the riverbanks); and
  • The culling of otters (e.g. for their fur, for sport or to reduce the number of fish taken from fisheries by the otters).

Following the ban on hunting in 1978, and increased controls on pesticide usage, otters have made a large comeback in Britain and their presence can be noted by the increasing number of droppings and footprints around our rivers. Otters are also protected under the Wildlife and Countryside Act (1981), which states that you are breaking the law to capture, kill, disturb or injure otters, damage or destroy a breeding or resting place, obstruct access to their resting or sheltering places, possess, sell, control or transport live or dead otters or parts of otters.

Image 2: More and more otter footprints are being seen. Photo © Mark Satinet

The increasing otter population does have potential to cause concern within the fishing industry. However, organisations such as the UK Wild Otter Trust, the Angling Trust, the Predation Action Group and independent fishery owners are working together to help educate stakeholders, raise awareness and continue to improve the outlook for otters, fish and other wildlife.

Image 3: Otters will come out of the water to eat their prey. Photo © Darin Smith

Although otters are great predators, it is also proven that over time, a natural balance will form between predator and prey. In the long-term, it is hoped that otters can re-establish populations across the UK and play a key role in river ecology, even helping to keep in check the spread of invasive species, such as crayfish which they are known to eat.

Eurasian otters are an incredible species. Below are some interesting facts about them:

  • They are said to be the most territorial of all the species of otter in the world. The area that they protect can be up to 25 miles wide. However, most of them are observed to have a territory of about 11 miles.
  • Offspring are born about 61 days after mating takes place. One to four pups may be born, which is different from most of the species that only have one at a time.
  • Pups will not be taken into the water to swim until they are about 2 months of age. This is because their coat hasn’t developed properly yet to keep the water from getting into their skin.

Image 4: Two otters playfully swimming together. Photo © Darin Smith

Sources and further reading