Skip to comments.Home and away: Bat uses magnetic compass for long flights
Posted on 12/07/2006 6:40:21 AM PST by FLOutdoorsman
Scientists believe a species of bat has an inbuilt magnetic compass to find its way home over long distances, in addition to its famous echolocation, which guides it around its neighbourhood.
Princeton University batologists used radio telemetry aboard a small aircraft to track big brown bats (Eptesicus fuscus) that were released 20 kilometers (12 miles) north of their home.
They first tested a "control" group of bats, which headed due south towards the roost without a problem.
Two other groups of bats were then exposed to a false magnetic field for 90 minutes, comprising 45 minutes before and 45 minutes after sunset.
One field was 90 degrees clockwise and the other was 90 degrees anticlockwise from magnetic north.
The point of this was to see whether the bats used Earth's magnetic field as a guide and, if so, to see whether the bats used sunset or the stars as an additional cue.
The "clockwise" group of bats flew due east, while the "anticlockwise" group went due west, suggesting that they had been using a magnetic compass that may have been calibrated by the sunset.
Some of the bats, though, corrected their course and arrived home safely, which implies that, like homing pigeons, they can make a fix if a navigational glitch occurs.
The research appears on Thursday in Nature, the weekly British science journal.
Meanwhile, another study, also published by Nature, sheds light on a remarkable bat species whose tongues are one and half times longer than their bodies.
The nectar bat (Anoura fistulata) lives in the cloud forests of the Ecuadorean Andes, feeding on flowers whose nectar is hidden at the end of long funnels.
The bat not only depends on these plants, called corollas, for its survival, it also pollinates them -- an example of convergent evolution whereby two unrelated organisms independently evolve similar traits.
I thought they used OnStar..........
So THAT'S how Nancy Pelosi fnds her way to Washington!
It will be interesting to see what happens once polar shift occurs.
They carry it in a little pouch on their tummies and pull it out to check course periodically.
They were placed in spherical cages where the celestial sphere was represented by pin holes that were lit and twinkled. The Northern Hemisphere's constellations were represented. The bottom of the sphere was covered with ink flim. The sphere was rotated and the birds would jump as if to fly and their leap patterns were recorded on clean paper sheets below the star pattern. Their tracks demonstrated that they responded to star patterns! Not only was there a compass to guide them but stellar navigation ability as well.
Another interesting finding was the time sense that these migratory birds have. It seems that the biological clock in the male bird is such that their genitals remain "small" until they reach their winter homes. Then their geneitals grow to about 10% of their body weight and then.... Woo! Woo! (I know let the ballsy banter begin!)
I guess that's why so many pregnancies occur after a southern sojurn. Aruba anyone?
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