Otters are the only truly semi-aquatic member of the Mustelid family which includes Badgers (Meles meles), Polecats (Mustela putorius), Pine Martens (Martes martes), Weasels (Mustela nivalis), Stoats (Mustela erminea) and Mink (Mustela vison). There are 13 known species of otter in the world but the only one found in the UK is the European (or Eurasian) Otter.

Otters are medium to dark brown in colour above, lighter underneath and approximately 1-1.2m in length. They have short legs, webbed feet and claws, a long stream-lined body, small ears and a broad muzzle with sensitive whiskers around the snout to help detect prey. They have 2 layers of fur - a thick waterproof outer one and a warm inner one. Otters usually live an average of 4 years in the wild although they can reach 8-12 years. They breed only once every 2 years as the cubs remain dependent on their mother for a year. Their diet mainly consists of fish, but may also include birds, small mammals, amphibians, crustaceans and molluscs. Otters rest in structures called holts, which are often cavities formed under tree roots, but drains, caves and holes in rockfalls are also used. They will also rest in dense vegetation (called couches). Otters are territorial and generally solitary, with territories ranging from 1 km to 40 km depending on the food supply available. Otters mainly live along rivers, but they are also found in canals, marshes, small streams, ditches, ponds, lakes, estuaries and coastal areas.


In 1978 the connection was first made between the decline in Otter populations and the widespread use of organochlorine pesticides in farming (Chanin & Jefferies, 1978). As a result, Otters were given full legal protection under Schedule 5 of the Wildlife and Countryside Act 1981 (as amended by the Countryside and Rights of Way Act 2000). The Otter is a European protected species included in the Conservation (Natural Habitats etc.) Regulations 1994, and is also listed in the Bern Convention and the Convention on International Trade of Endangered Species (CITES) and requires special protection measures under Annex 2 of the European Habitats Directive (92/43/EEC) which requires the designation of Special Areas of Conservation (SACs) for sites supporting important Otter populations. It is thus an offence to:

intentionally kill, injure or take an otter from the wild;

possess live or dead animals or any parts thereof;

intentionally or recklessly damage, destroy or obstruct access to any place used for shelter or protection by an Otter or to disturb an Otter whilst it is using such a place;

sell, offer for sale, possess or transport for the purpose of sale any live or dead animal or part thereof.

When considering planning applications, the authorities are required by law to take account of protected species and the conservation of habitats. A detailed ecological survey is usually required before planning permission can be granted.



The Countryside and Righs of Way Act places legal emphasis on developers to survey for this species prior to obtaining planning permission. Because Otters avoid disturbance and are largely nocturnal, survey and monitoring usually has to be carried out by searching for signs such as footprints and spraints (droppings) and recording habitat features and weather conditions at the time of survey. Surveys can be undertaken at any time of year and must be undertaken by a suitably experienced ecologist.


A development licence must be obtained from Natural England for checking holts or for carrying out work that may disturb Otters. Licences must be issued prior to commencement of works and should be applied for at least one month in advance of the start of works. Mitigation measures must also be in place, and only in extreme circumstances will the licensing authority permit the destruction of holts or other Otter resting places. Otters can breed at any time of year, therefore there is no preferred season in which to undertake operations in order to limit disturbance. Works may have to be delayed if Otters are found to be breeding on site.