The Tao of Sharks

Despite Civilization
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Civilization has not blunted our hunger for knowledge and experience, summed up by that famous mountaineer—because it is there. Or possibly the old adage from the Mafia applies, the one about keeping your friends close and your enemies closer. Photograph cruising great whites and tiger sharks from behind the bars of a submerged jail cell on your next vacation. Tell all the friends back home about it. The best part was when that 16-footer banged his snout against the bars. So beautiful and deadly. Just doing what sharks do. Magnificent creatures really. But you don't want to swim in their midst, because then they might do what sharks do—to you. A shark is the ultimate consumer. Even we can't match his wanton lack of discretion. Little fish, big fish, elephant seals, horse heads, car tires, anchors, metal pipe, glass bottles, jumper cables: GULP. A shark accomplishes all of this with his eyes wide open, which is a lot more than most of us can say.

A very large percentage of a shark's brain is devoted to processing smells. The requiem shark can detect one part of tuna juice in 25 million parts of seawater. The latest studies have shown that a shark's vision, once thought poor, is actually acute, even extraordinary in some species. Housed in the oversized snout of many sharks is a bank of electrosensors. Water is an excellent conductor of electricity. Every living thing waving or swimming or bobbing in the sea creates small pulses of electricity. The earth itself creates magnetic fields, which sharks may use to navigate and migrate. More research is needed in this area, but already we can say with a good deal of certainty that the ocean, as far as a shark is concerned, is by no means a featureless, watery void.

There are no places left on earth we have not explored, but there are places we know we don't belong. We visit these places—the snowfields and barren outcrops of the highest mountains; the life-killing heat or cold of deserts and arctic lands; the blue-green expanses of oceans and seas, featureless and unsettling to our eyes where there is nothing on the horizon—and visiting is good. We reaffirm what our bones and blood tell us: that our place lies in the vast middle ground of grasslands, temperate and equatorial forests, woodlands, savannas, and river valleys. Of all the places we do not belong, the oceans, which cover most of the planet's surface, are the most inhospitable of all. We are, absolutely, fish out of water.

Most fish are cold-blooded, with no internal means for regulating their body temperature. One group of fish—one group of sharks, specifically—are different. The mackerel sharks, which include the great white, mako, thresher, and the porbeagle, maintain internal body temperatures 45 to 50 degrees F higher than surrounding ambient water temperatures. Muscle activity and a series of biochemical reactions produce the heat, which is distributed through the shark's body by the flow of blood.

Published: 28 Apr 2002 | Last Updated: 15 Sep 2010
Details mentioned in this article were accurate at the time of publication
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