No one has ever seen one asleep, although they may be spied basking in the sun on the surface on a lazy summer day, or resting on the sandy bottom where it is warm and safe. But the golden, restless, ghostly eyes are alert for either enemy or prey. Omnivorous, fated to be ever hungry, relentless, savage, the tiger of the sea never relaxes his vigilance, never abandons his ceaseless search for food which is gulped down his white throat whole. From birth in the depths, a shark has to keep his great lunate tail waving in the sea lanes, his nose keenly alert for odors indicating succulent tidbits or a juicy feast to replenish energy burned up in his perpetually active muscular system.
Sharks are the greatest fish in the world, and the most invulnerable.
In every sea, in every clime, they glide silently up brackish river mouths, play in sunlit tropical waters, follow liners across the trackless oceans, migrate by millions up and down the shores of continents, and even live at the 200-fathom mark under the ice fields of Greenland and the Arctic. They have dominated their subsea domain against even the dangerous rivalry of the fearsome monsters of the past, and now have only themselves to fear. Despite their uncounted numbers through the ages, mankind only recently is beginning to learn something of their habits, their diet, and the uses to which the dead brutes may be put. There is something indefinably dreadful in the very appearance of these sea monsters, inspiring the utmost terror in the unprotected swimmer. The sight of a shark's ugly green fin slicing in zigzags along the surface, then submerging to become an acute menace, drives terror into the heart of the stoutest seaman.