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Sticker of North American medicinal leech
Bug card No. 3012 of 4,939

North American medicinal leech

Macrobdella decora
Name means: “Macrobdella means big leech in Greek”
Eats: BloodSnails, slugs and wormsPonds, rivers and shoresNo legsNot an insect, but a bug cousin

The North American medicinal leech is a slippery worm that lives in fresh water. Its back is greenish-brown with a row of little orange or red dots, and its belly is orange with black spots. It has ten tiny eyes arranged in a horseshoe shape.

Fun fact: this one is not an insect at all, it has no legs! But kids find it on every bug hunt, so it lives in Bug Wiki too.
Lives in
Eastern North America, from southern Canada to the nearby United States, and a few places in northern Mexico
Length
5 to 8.5 cm (2 to 3.3 in)
Top speed
about 0.03 km/h (0.02 mph)
On foot, estimate
Can it hurt you?
Can bite
It can bite to drink blood, but it is not dangerous. If one sticks to you after swimming, ask a grown-up to help take it off.
What does it eat?
It sucks the blood of animals with backbones, sometimes people too. It also eats eggs, larvae and other small water animals.
For real!Photo of North American medicinal leech
Picture by Original photograph by Owen Strickland. CC BY 4.0, via Wikimedia Commons.

How big is it?

How long is it?

North American medicinal leech about 8.5 cm long (3.3 in)A toy building brick about 3.2 cm (1.3 in)A crayon about 9 cm (3.5 in)A banana about 18 cm (7.1 in)
as long as 2.5 toy building bricks in a rowneeds 2 minutes to cross a dinner table

How big is North American medicinal leech compared to YOU?

Just maths in your browser. Nothing is saved or sent anywhere.

How fast is it?

cool stuff

Fun facts

1

It has three jaws, each with a row of about 65 very sharp little teeth that work like a saw.

2

Its stomach takes up most of its body, so it can hold a big meal.

3

Its spit has a special blood thinner that may be found in no other animal.

4

Its scientific name Macrobdella means big leech, even though it is only medium-sized.

you asked

Most asked questions about North American medicinal leech

?Does the North American medicinal leech bite people?

Yes, sometimes. It is not dangerous, but a grown-up should help remove it.

?How big is the North American medicinal leech?

About 5 to 8.5 centimetres long.

?Where does the North American medicinal leech live?

In ponds, lakes and streams in eastern North America.

For bug experts

Scientific name
Macrobdella decora
Named by
Say, 1824
Group
Snails, slugs and worms
Family
Macrobdellidae
Classification
Clitellata > Arhynchobdellida > Macrobdellidae
Lives on
North America

Where the facts come from

  1. Macrobdella decora (Wikipedia, CC BY-SA 4.0): what it looks like, where it lives, what it eats, sizes and fun facts, retold in simple words.
  2. Picture by Original photograph by Owen Strickland. CC BY 4.0, Wikimedia Commons. The sticker of this bug is drawn from this picture.

If we got something wrong, sorry, we are bug fans, not a science journal. Tell us at [email protected] and we will fix it.

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