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the exception of the Shortfin Mako, who typically dwells in warmer waters. Present day sharks are primarily cold water creatures. Those that are sighted in warmer waters are simply just visiting. The only thing that sharks have in common are gill slits. Over a 400 million year period, the shark has evolved into the perfect ocean predator. Sharks are masters of seven senses. Sharks see better than cats, smell 10,000 times better than humans, and have a highly developed sense of taste. Their hearing is excellent and they can sense the slightest differences in pressure, feel currents, and even detect electrical fields of their prey. Their food spectrum ranges from plankton and mussels, to fish, birds, and marine mammals.

Sharks are at times mistakenly categorized as fish, although they are only distantly related to the classical bony fish. Those evolutionary lines of cartilaginous and bony fish separated about 400 million years ago. Shark skeletons are composed of cartilage, which is dense and composed of collagen fibers and it provides strong and flexible support. Sharks also lack a gas filled swim bladder found in most bony fish. A swim bladder holds gases and acts like a flotation device inside of fish, keeping it from sinking. Sharks are able to remain somewhat buoyant without a swim bladder because of their enormous oily liver. Most sharks must constantly swim to keep from sinking. This movement is also necessary to keep a flow of water over the gills in order to provide oxygen.

Within the darkened waters of the ocean is one of evolution's perfect predators; the shark; constantly moving and searching for its next meal. Some have worshiped the shark as gods, others simply fear them. But one thing remains clear, the shark commands respect, and after 400 million years of ruling the oceans, this majestic creature of the deep is here to stay.

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