Sussex Wildlife Trust: Otters

Otters are a semi-aquatic mammal and a member of the Mustelid family (the same family as badgers and weasels.) There is only one native species of otter in the UK - the Eurasian otter (Lutra lutra). The Eurasian otter is found in many countries across the world, from Ireland to Asia.

Otters have been either endangered or extinct in nearly all of their native countries, however they are now mostly recovering across Europe. One of the main reasons for their decline was pollution of our rivers and wetlands. Thankfully a lot of the worst river pollution has since been cleaned up.


Otters are a flagship wetland species, at the top of the wetland food chain. We know that if otters are healthy, then humans and all the other wetland species in the food chain below them are also healthy. Conservation measures which help otters therefore help a whole range of other species including fish, birds and insects.

An otter needs three important things in order to survive:
1. A plentiful food supply.
2. Clean, unpolluted water.
3. Quiet, undisturbed places to rest and breed.

Otter dens are called holts (permanent resting places) or hovers (temporary resting places) and are usually found in quiet hollows in the root systems of riverside trees, small rocky caves, pollarded tree crowns, patches of reedbed, old badger setts or dense scrub.

The following are useful guides on otters:
Adult otters can eat up to 1 kg of food a day of food which is seasonally abundant. Their favourite snack is Eels (Anguilla anguilla), but they also eat fish, crustaceans (such as crabs and crayfish), amphibians (frogs etc.), molluscs, occasionally small birds and mammals and even slugs and dragonflies.

Current Conservation Status:
Under UK law the otter is protected by the Wildlife and Countryside Act 1981 under which it is an offence to kill, injure or knowingly disturb an otter, damage or obstruct an otter holt. The otter is a UK Priority Species.

Current threats to British otters:
Pesticides and sheep dip pollution caused the initial decline of the otter but there are still many things which are hindering their recovery. These include:-

• Habitat destruction and fragmentation: – meaning otters have to travel large distances to find food, mates and shelter, with many hazards on the way.

• Disturbance by humans and dogs. Otters are shy and nocturnal animals. During the day they need secluded places to rest. If disturbed too often they may suffer from stress.

• Roads and railways. The main cause of otter deaths is roads. In winter when rainfall swells rivers, otters are forced to cross roads to travel from one fragment of habitat to another and they frequently get run over.

• Mink traps, crayfish traps and eel fyke nets are a threat but can be fitted with otter guards.

• Pollution can directly harm otters or can     reduce/kill the food available for them to eat.

• Direct persecution is still an issue, despite it being illegal to kill otters.

Image Credit: otter derek-middleton-sussex-wildlife-trust