A bloodsucking worm with a flat, segmented body that tapers at both ends but is broadest toward the posterior part. Leeches measure from about a half inch (1.3 centimeters) to three or four inches (7.6 or 10.2 centimeters) in length. Leeches have a disk or sucker at each end of the body, the one at the head end being equipped with biting jaws. They are bisexual, that is, both sexes are present in a single creature. Most leeches live in fresh water, but there are also marine and terrestrial varieties.
Leeches are found in great numbers in many streams and rivers of the Middle East. They present not only an annoyance but also a danger to swimmers and to men and animals that might drink from leech-infested waters. The young of one variety, when swallowed with the drinking water, attach themselves to the nasal cavities, larynx or the epiglottis of their host. They grow rapidly and are not easily removed. Their presence can hinder breathing and this, as well as loss of blood, sometimes proves fatal to the victim.
Sole mention is made of the leech at Proverbs 30:15, where the reference is to insatiable greed, it being stated that “the leeches have two daughters that cry: ‘Give! Give!’” Bible commentator Cook suggests that the leech’s greed is here viewed as its ‘daughter,’ spoken of in the plural to express intensity. Others consider the “two daughters” as referring to the two lips of its bloodsucking disk. A leech may consume about three times its own weight in blood, a strong anticoagulant in its saliva ensuring a continuous flow from the victim.