National Geographic : 1954 Mar
beacon that was our only guidepost. Calling it an evening, we hauled in the overboard light and headed shoreward. Within the hour we had poured out the fragile contents of our pails and washtub into proper tanks fed with running sea water at the Lerner Ma rine Laboratory on North Bimini.* But, alas, all the specimens were dead next morning, both "but terflies" and adults. Dr. Charles M. Breder, Jr., ichthyologist at the American Museum of Natural History, told me later that members of the flying fish family rarely do well under artificial conditions. For one thing, these fish have a short, nearly straight digestive tube which allows for lit tle reserve absorption; whereas most animals have a coiled intestine or some other anatomical device for slowing down the passage of food. Feeding on the sea sur face, where plankton is always plentiful, these baby flying fish never have had to develop a means of maintaining a food reserve. This seems a likely explanation, at least, of their speedy Wings as Diaphanous as a Grasshopper's Support the Flying Fish The spectacular glides of flying fish delight travelers in all warm seas. Contrary to popular impression, the fins do not vibrate in the air. Momen tum comes from a sharp burst of speed under water, then a rapid sculling with the tail as the fish taxies along the surface. Updrafts sometimes catch the rigid-winged gliders and carry them forward 1,000 feet or more. Flying fish have been known to sail through open portholes. This specimen, held by the author's wife, came to a light in the Gulf Stream off Bimini (page 397). death after capture. Immature flying fish caught later were kept alive for days by loading the aquarium with tiny brine shrimp on which the fish could feed continuously. Some Fish Are Aquaplaners What ocean voyager has not heard the cry "Flying fish!" and hurried to the rail to see a "flock" zipping through the air a few feet above the sea's surface. Flying fish are not wholly unique in this aerial accomplishment. Some of their rela tives, the needlefish, halfbeaks, and skippers, are would-be aviators too. But not possessing the great fanned fins of the flying fish, these pretenders merely skim across the water, sculled by the rapidly vibrating tail fin. Only when evolution gave fin planes to fly ing fish was true flight achieved, a flight that resembles an airplane's rather than a bird's. There is no wing flapping; spread fins re main essentially rigid as the fish glides aloft (see above). Aerial adventure among fish appears to have but one motivation-a means of escape from predators or other disturbance. Take off is preceded by rapid acceleration close * See "Man-of-War Fleet Attacks Bimini," by Paul A. Zahl, NATIONAL GEOGRAPHIC MAGAZINE, February, 1952.