Medicinal leech in water


Invertebrates play crucial roles in keeping ecosystems healthy and functional. From pollination to waste recycling, to filling crucial links in food webs, invertebrates do it all! If we want to save big, fluffy species, we need to conserve wee beasties too – even bloodsuckers like the medicinal leech (Hirudo medicinalis).  

This species is a type of worm, but unlike their land-dwelling earthworm cousins, medicinal leeches spend most of their time in water and feed exclusively on blood. They have two suckers, a posterior (back) sucker, used as leverage to move and an anterior (front) sucker, used for feeding.

These fascinating animals were historically used at a massive scale in medicine around the world. Overharvesting of leeches for medical purposes, combined with habitat loss and freshwater pollution has resulted in a decline of the species. Medicinal leeches are found in just three locations in Scotland and are classed as Near Threatened globally by the IUCN.  

To boost the population of medicinal leeches in Scotland, in 2023 RZSS started a conservation breeding programme for the species in a specially designed facility at Highland Wildlife Park. Working in partnership with Buglife as part of the Species on the Edge Initiative, we aim to breed enough leeches to start new populations in suitable lochs around the country.

Our Partners

Project type

Conservation translocation icons

Conservation translocation

The team

Adam Button

Adam Button

Experienced animal keeper

Georgina Lindsay

Georgina Lindsay

Conservation manager

Helen Taylor releasing dark bordered beauty moths

IMAGE: Jess Wise 2023

Dr Helen Taylor

Conservation programme manager

Project updates

Date: October 2023

Medicinal leeches have arrived at Highland Wildlife Park! Our team went out to survey a medicinal leech population near Oban with Buglife and Species on the Edge. Having found over 30 medicinal leeches in a two-hour period, the population was deemed to be a good source for the new conservation breeding programme. The team collected a mix of adult and juvenile leeches who are now in their new homes in a specially designed facility at Highland Wildlife Park. After settling in, they will go into torpor for the winter and wake up for the breeding season in spring.

Medicinal leech


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