Medicinal leeches poised for comeback in Scottish Highlands

Project aims to release hundreds into lochs and streams after centuries of habitat loss and exploitation

The medicinal leech is one of nature's least loved hunters. Armed with three strong interlocking jaws and with a taste for blood, they will swim hungrily towards humans, deer or cattle that wander into their ponds to bathe, fish or drink.

Yet this small predator is the focus of an unlikely reintroduction programme by conservationists working in a small laboratory deep in the Scottish Highlands, at a wildlife park best known for its polar bears, wildcats and wolves.