Known as the vampires of the Great Lakes, lampreys are jawless blood sucking parasitic creatures. Although they resemble an eel, due to their lack of scales, they have been known to range in size from five inches to forty inches in length.
As already stated above, the lamprey is a fish parasite. With a suction cup type of mouth, lined with a multitude of very sharp teeth, the parasite initially clamps down onto its prey. Then, it will use its rows of sharp teeth, grinding them against the fish’s scales to remove them, allowing the lamprey access to the fish’s skin. Then it is just a matter of sucking the fish’s blood and body fluids out. Keep in mind, the lamprey doesn’t let any part of the fish go to waste, as it will also feed on the fish’s scales, flesh and bones. It has been estimated that forty pounds of fish are killed each year by just one lamprey.
The suction cup mouth comes in useful for traveling as well. The lamprey can clamp down on much larger fish and use that fish as a means of transport. When not being carried by another fish, the lamprey can move quite well on its own. With the manner in which its body is shaped, it uses the water to pull it along, rather than pushing against the water like most aquatic lifeforms.
There have been very little in the way of reports of lampreys attacking humans, as the lampreys feel that humans are too big and intimidating. However, if a lamprey gets hungry enough, say from starvation, they have been known to attack humans then.
The biggest worry about the lamprey is that they have no natural predator in the Great Lakes so their numbers are running rampant and out of control. Without a way to control the population, the lampreys are more often than not attacking many of the fish in the Great Lakes that humans eat, such as trout. There are additional worries that the toxic mucus the lampreys give off may very well be contaminating areas of drinking water.