The otter has made one of the most remarkable wildlife recoveries of any UK mammal, returning to rivers across Britain after near-extinction due to organochlorine pesticides and persecution.
Otter recovery demonstrates that wildlife welfare can be transformed by removing the primary cause of harm. Road mortality is now the main welfare threat: otters following rivers encounter road culverts where they climb onto roads rather than swim through. Otter ledges in culverts allow safe passage under roads.