Leech

A leech is a type of worm that lives in water and feeds on blood. It can grow up to 12.7 centimeters (five inches) long. It has a flat body with a suction pad at each end. Its mouth has three teeth that pierce the skin of a person or animal. The leech produces a substance that keeps the blood from clotting while it feeds.

The medicinal leech (Hirudo medicinalis) lives in springs and ponds from the Negev Desert to Galilee. It can attach itself to people and animals that enter the water and feed on their blood.

It is not clear what kind of leech Proverbs 30:15 refers to. The verse may refer to the horse leech (Haemopis), perhaps because of its greedy feeding habits. A small horse leech can enter an animal’s mouth or nose while the animal drinks water. A leech that weighs 14.2 grams (half an ounce) can consume up to 71 grams (2.5 ounces) of blood. It can then survive for 15 months without feeding again.

See also Animals.