Lampreys are animals without bones or jaws, and yet they are prototype vertebrates. Related to hagfishes, the lampreys are cartilaginous fish with sucker-like mouths and are 550–450 million years old. These two groups comprise the agnathans and are reminiscent of Pikaia gracilens, the Cambrian fossil believed to be close to the first vertebrate. Despite lampreys and hagfish lacking bone and tooth enamel or other hard parts, they are still surprisingly well preserved in the fossil record. However, as a result of a paucity of fossils, the phylogeny of these groups is controversial and incomplete. Current evolutionary evidence suggests that hagfishes preceded the lampreys, with all three extant lamprey families coming from a common ancestor. The southern lamprey, Geotria australis, spends the first 4–5 years of its life in freshwater streams of southern hemisphere lands including Australia, New Zealand, South Africa, and South America. During this time, its eyes are only poorly developed. Although usually thought of as parasites, lampreys actually begin life as filter feeders, feasting mainly on detritus and unicellular algae. During …