Mammals
Eurasian Otter
Lutra lutra · also called common otter
Marking its territory with droppings left conspicuously along the riverbank, a Eurasian otter serves as a living signal of a healthy waterway, its dramatic recovery from near-extinction now standing as one of Europe’s clearest environmental success stories.
Overview
The Eurasian otter, Lutra lutra, is a wide-ranging, semi-aquatic mustelid native to wetland and coastal habitat across Europe and Asia. Its role as an indicator of river health, dramatic recovery from pesticide-driven near-extinction, and territorial scent-marking behaviour make it one of the most ecologically significant carnivores found across its vast range.
A comeback measured in clean water
The Eurasian otter’s return to rivers it had vanished from decades earlier tracks almost exactly with improvements in water quality across Europe, making its recovery one of the clearest wildlife success stories tied directly to pollution control.
Status
Least Concern and increasing, having recovered significantly across much of Europe following pesticide bans and improved river water quality.
Eurasian Otter: common questions
Why is the Eurasian otter considered an indicator species?
This species is widely used as an indicator of healthy river ecosystems, since its return to a waterway generally signals improved water quality and abundant fish stocks, making its presence a useful proxy for overall environmental health.
How did the Eurasian otter recover from near-extinction?
This species was reduced to near-extinction across much of Europe by the mid-twentieth century due to pesticide pollution and habitat loss, before recovering dramatically once the most harmful chemicals were banned and river water quality improved.
How does the Eurasian otter mark its territory?
This species marks its territory using droppings, known as spraint, deposited at prominent locations such as rocks and logs along the waterway to communicate with other otters passing through the area.
Does the Eurasian otter live in groups?
No, this species is largely solitary and territorial, with individual home ranges that can stretch for many kilometres along a river or coastline.