Migration Facts

Just a few of the amazing reasons I am enthralled by migration (from "Secrets of Animal Navigation" by Michael E. Long, National Geographic June 1991): Recent researchers, using techniques of the neurosciences, microbiology, and bioacoustics and such fundamentals of physics as electricity and magnetism, are demonstrating that the senses of the creatures of land, sea, and air are incredibly acute. Imagine: • A homing pigeon senses changes in altitude as minute as four millimeters. Pigeons also see ultraviolet light and hear extremely low-frequency sound that emanates from wind coursing over ocean surf and mountain ranges thousands of miles distant. • A honeybee detects infinitesimal fluctuations of the earth’s magnetic field that only the most sensitive magnetometers can measure. • A shark recognizes an electric field on the order of five-billionths of a volt per centimeter. • Some animals may be able to “see” the earth’s magnetic field, a proposition about as staggering as “seeing” the force of gravity. In 1975 Richard Blakemore discovered "north-seeking bacteria" that responded to a battery of magnetic tests - even dead bacteria aligned themselves appropriately! On vacation in Utah, scientist Arthur Hasler led his family to a favorite waterfall of his boyhood. “As we approached, the waterfall was hidden by a cliff,” he recalls. “Suddenly I experienced the wonderful fragrance of mosses and columbines growing near it that I had not smelled since I was a boy. The names of my school chums whom I had not seen for 20 years flashed back. And then it occurred to me: Maybe a salmon does this!” In fact, salmon remember the smell of the rivers they traveled down, their home stream, and the genetic pheromones of their kin. But the sensory detection that scientists have discovered still don't explain how animals navigate longitudinally - which means, possibly, there is a type of sensory input that animals have that scientists have yet to imagine!