Just as with other large predators, from Grizzly Bears to Wolves, humans have hunted these species and in many regions of the planet have brought them to near or complete extinction. New scientific studies show the critical importance that those animals had and have on the ecosystems that they were or are a part of. As for the oceans, sharks play this critical role. There are over 400 shark species in the world, and in this episode we will hear about their function, their challenges, and what is being done to protect them.