Blood Sucking Medicine
How would it feel to spend an entire day with your friends, jumping off a rope swing into a warm stream? Now imagine getting out of the water and looking down, only to find your legs covered with—leeches! Pulling off leeches is not exactly the way you would want to end such a fun-filled day. While the thought of pulling leeches off your legs may seem gross, imagine being in a hospital and watching a doctor place 3-5 leeches underneath your bandaged arm! Today, while it is rare, leeches are still used to control bleeding in some patients.
Leeches are classified as annelids, or segmented worms. They are related to earthworms, but unlike some other types of worms, they have suckers at the end of their bodies. One sucker has sharp jaws to cut through the skin of its host. Once they have cut a hole, they then inject a substance that keeps the blood from clotting, allowing them to feed until they are full. Unlike many parasites, leeches most often live outside the body of their host—they are externalparasites. Being a parasite means that they live off of other organisms without helping the host in return. Does it make sense that leeches (which need other animals in order to survive) could have evolved? No. In fact, God created both leeches and their hosts.
There are over 130 different species of leeches, most living in water. However, some leeches have the ability to live on land. While they are famous for their bloodsucking ability, not all leeches feed on blood. Some feed on insects, small worms, or decaying flesh. While leeches would never win a relay race, they do manage to get around. They occasionally hitch a ride with their host, swim in the currents, or crawl like other segmented worms.
During medieval times, doctors believed patients could often be cured by having their blood sucked out—thus, leeches were used to “cure” people of their illnesses. Surprisingly, leeches are used today because the substance they secrete helps keep blood flowing through the tissue. This prevents the skin from scabbing over too quickly, and promotes healing from the inside out. Amazing bloodsucking creatures!