SEATTLE—Not all babies born or hatched at Woodland Park Zoo are warm, cuddly, furry and feathered. Adding to this year’s baby boom, the zoo is proud to announce its newest hatching: approximately 30 medicinal leeches (they’re very difficult to count!)!
The new leeches are among the many animals born or hatched at the zoo since the pandemic including snowy owls, penguins, a tapir, gorilla, pudu and mountain goat.
It will take about two to three years for the new leeches to reach their adult size of approximately 6 inches.
The leech hatchlings are the offspring of multiple adults the zoo rescued four years ago. U.S. Fish and Wildlife Service confiscated the adult leeches from an individual traveling from Russia to the U.S. who attempted to smuggle more than 40 adult leeches in water bottles. Woodland Park Zoo accepted all the leeches into its care.
Earlier this year, the zoo received 22 more adult leeches from a U.S. breeder; the adult leeches from Russia immediately started breeding with the new additions.
“Woodland Park Zoo works closely with wildlife agencies as a partner for consultation and providing a safe home for reptiles, spiders, and other animals on a case-by-case basis, and in this case, leeches,” said Erin Sullivan, an animal care manager at Woodland Park Zoo. “We’re very excited about the newest members to our zoo family!”
Two years ago, the zoo rescued 250 tarantula spiderlings that were confiscated by U.S. Fish and Wildlife Service from an importer.
Medicinal leeches are rare in zoos accredited by the Association of Zoos & Aquariums (AZA), like Woodland Park Zoo. “Since medicinal leeches are not a species commonly found in AZA-accredited organizations, we are currently trying to collect data on who has them, who is breeding them and who would like them for educational programs,” said Sullivan. “So far, we have already had interest in our leech hatchlings from other AZA organizations who would like to have them on exhibit.”
Feeding leeches can be a messy business. “We feed our leeches blood-filled sausages by filling natural sausage casings with beef blood, tying the ends and warming them up to about 100˚F. We then let the leeches go to town!” said animal keeper Megan Blandford. They don’t need to be fed often. “After an initial feeding immediately after hatching, the leeches will be fed only four times a year. But in the wild they regularly go an entire year without eating!”
Visitors fascinated by leeches can see the adults and babies in Bug World when the temporarily closed building reopens to the public. To keep visitors safe, Bug World and other indoor areas remain closed including Family Farm, Zoomazium, the Tropical Rain Forest and the Historic Carousel. Visit www.zoo.org/visit for more information.
For many, leeches evoke the “ick” and fear factor. However, in medieval and early modern medicine, medicinal leeches were an important medical tool for a long-standing tradition of bloodletting, which helped balance the humors (blood, phlegm, black bile and yellow bile), and to treat other illnesses and infections.
Today, there is an increasing demand for medicinal leeches because of the comeback in leech therapy and their value. Leech saliva contains a chemical called hirudin, a natural anticoagulant to prevent blood clots. This chemical keeps blood flowing to wounds to help them heal.
In today’s medical field, medicinal leeches are mostly used for plastic surgery, microsurgery, grafting and constructive surgery. Leeches are also prescribed for other ailments, including varicose veins, neuropathy, blocked arteries and osteoarthritis. Learn more about the valuable role of medicinal leeches.
Leeches are closely related to a subclass of animals that include the earthworm.
Only 15 of the 600+ species of leeches are used medicinally: Hirudo medicinalis, the European medicinal leech, is one of several species of medicinal leeches.
Medicinal leeches, a near threatened species, are protected in much of their natural range since they are nearly extinct in many of the swamps and pools they would naturally be found in, due to collection for use in traditional medicine.
Leech therapy is used to treat people with heart disease because of its potential to improve inflammation and blood flow. In the past few years, leech therapy has become an acceptable alternative therapy for people with vascular disease and disorders.
Medicinal leeches have three jaws with tiny rows of teeth. They pierce a person’s skin with their teeth and insert anticoagulants through their saliva. The leeches draw blood for 20 to 45 minutes at a time from the person undergoing treatment.
After the leeches lay an egg, depending on environmental conditions, it can take anywhere from three weeks to 11 months for an egg to hatch out between five and 200 babies.
With regular care and feedings, leeches can live five to six years in human care.
How to Help at Home
Take care to preserve wetlands for species that live there such as leeches, amphibians, turtles and other species that require this kind of habitat to survive.
Keep waterways clean by limiting the use of pesticides and chemicals in your yard. Never let oil, grease, or fertilizers leak into places where storm water run-off can carry them into waterways and wetlands.
Support wetlands conservation: Wetlands protect shores from wave action, reduce the impacts of floods, absorb pollutants and improve water quality for all.