Sharks have existed on this earth for over 400 million years, and for the most part have been one of the only species in earth’s history that has not been changed dramatically as a result of evolution Furthermore, in recent times since the onslaught of the industrial revolution, numerous pollutants and toxins have been introduced into the earth’s oceans, forests, and atmosphere resulting in cancerous development in nearly all forms of life. Incredibly, however, the amazing living machine known as the shark has survived literally unchanged and has rarely developed cancer despite the fact that almost all other creatures of land and sea get cancer regularly These prehistoric sea creatures have skeletons, unlike other animals, largely made up of cartilage, which is a tough yet malleable connective tissue. The fact that sharks do not regularly get cancer, that they have survived the test of time, and that they are composed mostly of cartilage has raised quite a bit of interest among scientists within the past twenty years