Twenty rare baby leeches hatched at Highland Wildlife Park, marking a significant step in reviving Scotland’s declining medicinal leech population.

In a breakthrough for conservation in Scotland, twenty rare medicinal leeches have hatched at the Highland Wildlife Park near Aviemore. This is the first success for a captive-breeding project designed to restore the native population of these remarkable invertebrates, which are now critically rare in Scotland. The project, led by the Royal Zoological Society of Scotland (RZSS) in collaboration with Buglife, a leading conservation charity, aims to eventually release the captive-bred leeches into suitable habitats across the country.

The leeches are descendants of a small population found in the wild in Dumfries and Galloway, one of the few remaining areas in Scotland where medicinal leeches still survive. These creatures, once abundant across Scotland, saw drastic population declines in the 18th and 19th centuries due to over-harvesting for medical use and the loss of vital wetland habitats.

Dr Helen Taylor, conservation programme manager at RZSS, expressed her delight at the recent hatchlings, saying, “It’s incredibly exciting to see these baby leeches hatching, which is much more than we were expecting at such an early stage in the project.” The success marks a promising start for the project, which could ultimately see medicinal leeches return to Scottish waters after centuries of decline.

Craig Macadam, conservation director of Buglife, echoed Taylor’s enthusiasm, stating, “Medicinal leeches have an important place in our medical history but are now one of the rarest invertebrates in Scotland. The success of the rearing programme at the Highland Wildlife Park is key in securing a strong future for medicinal leeches here.”

The medicinal leech, the UK’s largest leech species, can grow up to 20 centimetres (8 inches) long. Notable for their dark brown and yellowish colour, they possess five pairs of eyes and a powerful sucker lined with three jaws and around 100 small teeth. In the wild, these leeches primarily feed on fish and frogs, but they are also known to attach to larger animals, such as deer, sheep, and cattle when they wade into the water to drink.

These leeches are a protected species in the UK, where they remain in only a few areas in Scotland, specifically in Dumfries and Galloway, and parts of Argyll and Islay in the Inner Hebrides. Historically, they were valued for their use in bloodletting, a practice that involved the removal of blood to treat various ailments. While bloodletting has faded from modern medicine, leeches continue to play a role in medical treatments. Today, farmed leeches are used in surgery to help manage blood clots and improve circulation, with a dedicated leech farm operating in Wales to supply this niche need.

The recent success of this breeding programme could eventually pave the way for the return of medicinal leeches to their native habitats in Scotland’s lochs and wetlands. Hatchlings emerged from oval-shaped cocoons, which were nestled in moss, creating an ideal environment for their growth. The project’s long-term goal is to reintroduce captive-bred leeches to suitable locations where they can contribute to Scotland’s natural biodiversity.

The Highland Wildlife Park, operated by RZSS, has long championed the conservation of native species, and the breeding success of these leeches underscores its commitment to Scotland’s wildlife heritage. With continued support and collaboration, the park and its partners are hopeful that the medicinal leech population in Scotland can be stabilised and strengthened for generations to come.