National Geographic : 1952 Feb
186 National ieogral)p1hc 'llotograpler lUls M1arcen Like a Hitchhiker on an Airplane's Wing, a Remora Rides a Gray Shark Remoras, or shark suckers, cling to the big fish to snatch morsels from his meals. Their powerful suction discs make no impression on a shark's sandpaper hide, but a large remora may kill scaled fish by pulling away their protective plates. This five-foot gray shark (Carcharhinus) lives in a tide-swept pen on Bimini (pages 194, 195). About three-quarters of his brain is given over to the olfactory sense. Smelling out his meal, here a grunt floating belly up, he swims in ever-decreasing circles. He prefers the freshly killed fish to the live sergeant majors beneath him. Contrary to popular belief, he does not have to roll over to gobble a meal. completely submerged. Their amazing elas ticity enables them to descend into the salty depths as far as 50 feet, hanging there as a silent lure to unwary fishes and small marine invertebrates as well. No attempt is made to seek out prey; in fact, the tentacles are capable of only two motions, up and down. But if a fish merely brushes one of the tentacles, a thousand harpoonlike hypodermics, microscopically lin ing these long streamers, are instantly dis charged to pierce its body, each injecting a tiny drop of poison. The minute hollow threads do not with draw, but cling. As the fish struggles, it gets only more fouled up and thus receives addi tional hypodermic broadsides. In a short time the finny victim is para lyzed. Up lift the tentacles, like elevators, and deliver the hapless catch to the man-of war's eating tissues for digestion. Then down again they go, for more lethal angling. Floating shiplike, the Portuguese man-of war inhabits many of the globe's tropical seas. It thrives in the Gulf Stream, where, during certain brief periods of the year, countless thousands suddenly appear riding high and proud on the warm swells. Storms Wreck Man-of-War Fleets Storms and onshore winds are their foe, and a persistent blow may drive great fleets before it, wrecking and piling them up, as here in Bimini, on whatever beach, near or far, may loom ahead. Stranded, the men of-war quickly wilt and die as masses of ugly blue slime, or jelly, familiar to anyone who has trod Caribbean shores.