Scientific Name: Lutra lutra

Family: Mustelidae

Appearance: Otters are one of the largest mustelids, with thick brown fur and webbed feet. Length: 135cm. Weight: 10kg.

Natural history: As they feed on fish, amphibians, waterbirds and crustaceans, otters live close by rivers and lakes in underground burrows called holts. They are very territorial, and mark out their large territories using faeces called spraints. Some otters feed mostly on the coasts, but these individuals need a regular supply of fresh water to clean their fur.

The otter species found in Britain is the Eurasian otter. Many other otter species exist around the world, including specialist sea otters, giant otters reaching nearly two metres long, and clawless species.

Otters declined severely throughout Europe due to pollution of waterways. The most serious impacts of pollution are generally seen in top predators such as otters: the pollution from each contaminated animal they eat builds up in predators’ bodies, accumulating to huge levels. As environmental policies improve, otters are returning to waterways across the UK.

Image by Bernard Landgraf - Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=41335