Penguins
PenguinsMyopic little men in tuxedos, or highly efficient land/water animals? Recent research indicates there’s more to penguins than meets the eye. If you’ve every wondered what it would be like to be able to see as clearly under water as you can on land, just ask the nearest penguin.Most aquatic animals are short-sighted on land. Most terrestrial animals (and that includes us) are far-sighted under water. But researchers have discovered that penguins can apparently see equally well in both environments, because of the unique structure of their eyes. Penguins have to be able to see well under water because their diet consists mainly of plankton, molluscs, crustaceans, and the inevitable fish. Through a special slowing-down of their heart rate they’re able, like many other diving animals, to stay submerged long enough to search out and chase whatever catches their fancy. On dry land, it’s a different story-or has been up to now. Waddling along on their flat little feet, eyes fixed intently on the ground, penguins appear myopic, inefficient and generally out of place. In fact the reverse is true. During a recent stay on the Falkland Islands, a Canadian researcher discovered that penguins are able to recognize individuals and navigate the rocky terrain on which they live quite well. Long of body and short of leg, they probably poke their heads forward as an aid to balance. And as for looking at the ground, they’re merely-like us-keeping an eye on where they’re going. The human eye is adapted for aerial vision, which is why scuba divers-or even you and I in the local swimming pool-must wear goggles or a face mask to re-introduce air in front of our eyes in order to see clearly. Among vertebrates in general, the bird eye is frequently described as the most efficient. Its superior quality, combined with the fact that a large number of birds-cormorants, pelicans, seagulls, even ducks, as well as penguins-get their food from water, obviously deserved research beyond that possible in a controlled environment such as an aquarium or zoo. Professor Jacob Sivak of the University of Waterloo and his associate, Professor Howard Howland of Cornell University, had a chance to do that research recently. Their trip had but one purpose-to study the structure of penguins’ eyes while observing their natural habitat. The Falkland Islands, off the coast of Argentina, offered this opportunity, being one the few areas outside Antarctica where penguins can be found in large numbers. Three of the 16 known species were located there: the Gentoo, which live on flat areas right off the beach; the Magellan (also called Jackass), which live in burrows; and the Rock-hoppers, which live among the rocks along the cliffs. The Rock-hoppers were by far the most common, having a population of well over 100,000. The general...
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