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Animal Tracking in the Virtual Age

posted: 05/15/12
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The GPS collar on this elephant can record its every move.
Anders Lindgren/Tigress Productions |
Animal TracksHow does GPS work?, Mission to Mali Part 2: Retrieving the Collars

If you are one of those people who bemoans how technology deprives us of privacy, be comforted. It could be worse. You could be an elephant.

Take Lewis, a 43-year-old African elephant bull. When he wanders off contemplating attractive and available pachyderm-ettes, he no longer does so unobserved. Now, he carries his own audience everywhere, in the form of a GPS collar.

On the other hand, his audience has nothing but good intentions.

Humans have been tracking animals as long as we have been humans. First, we followed them by eyeing their tracks. Our next big technological leap was to make use the olfactory talents of other species, i.e., dogs. Another big step was to attach radio beacons to the creature we wanted to keep track of. It worked, but it took a lot of manpower. These days we have entered the age of Tang and astronaut pens, so why not track animals using space technology?

"It's a wonderful new era," says Bruce Mate, who uses crossbows to attach satellite transmitters to whales. "I can simultaneously track six species across five oceans. I couldn't have done that five years ago."

In the old days the point of all this animal spying was to get dinner. Nowadays it is to prevent the animal from becoming dinner, or piano keys, or objets d'art. Most, if not all, of high-tech tracking is for conservation. It also helps us understand how animals make decisions about where they spend their time.

GPS, or Global Positioning Systems, is the latest and greatest of tracking systems. There are GPS collars on elephants, wolves, bears, deer and soon, maybe even crocodiles. Quintin Kermeen, president of Telemetry Solutions in Concord, California, estimates that currently there are probably 2,500 collars out in the wilderness, gathering data about critter liaison and dining out habits.

It all started with caribou. Well, actually, it all started with the U.S. Department of Defense, which designed a system to keep track of its soldiers. They sent up 24 satellites, timed so that at least 12 would be available to any hemisphere at any time. The satellites send out signals that receivers use, in tandems of three or four, to trilaterate (something like triangulate) geographic positions. Once the satellites were sent up, the DOD allowed other users—like rental car companies, GPS makers and now, biologists— to use them. The first animal applications were initiated in 1992 by the Canadian government to track caribou.

Now wolves, bears, deer and moose sport the new collars. Six or seven companies compete to make lighter collars with bigger memories and VHF modems to send the data back to the researchers.

Iain Douglas-Hamilton was first to put them on elephants in Amboseli National Park, Kenya. The prototype weighed 12 kg (26.4 lbs), took two readings every 24 hours, and only lasted 10 days.

Now the collars weigh 4.5 kg (9 lbs), can take 50 readings a day, and record and transmit for a year. Douglas-Hamilton's newest collars download directly to the Web via satellite connection.

Biologists wax poetic about the advantages of GPS. With radio telemetry they would have to fly, drive or hike around for hours, even days, in search of a signal. Then if they had to do something like, say, eat or sleep, they'd lose the data and risk losing the signal again.

"The advantage of GPS radio tracking (now that we have proved it can survive elephant life) is that we get a continuous flow of high quality data that pinpoints elephant movements, in fair weather or foul, by day and night, up and down mountains, in and out of forests and across international borders," says Douglas-Hamilton.

GPS led to the discovery that elephants "streak" — not in the human sense of the word, since elephants other than the collar, run about naked all the time. But for Douglas-Hamilton streaking means that, when elephants decide to move, after hanging around one spot for days, they really move. They tear down a narrow corridor, changing whole ranges, without stopping.

The low-tech part of GPS is getting the collar on the elephant. After shooting tranquilizer darts from planes, the researchers have to work at crowd control. Collaring and drawing samples from a drugged elephant is easy, keeping her buddies at bay is not. In the Lost Elephants of Timbuktu, Douglas-Hamilton's team, along with researcher Anne Orlando, have a couple of tense moments working quickly to fit an elephant with a collar before the rest of the herd knows its missing. The risk of getting trampled is very real.

Tracking other animals can require alternative high-tech solutions. GPS won't work for whales, says Mate, because they never surface long enough for a satellite to trilaterate a GPS signal. Instead he uses "collars" that transmit signals directly to satellites, and the satellite analyzes positions using Doppler shift. It is not as accurate, carrying an error of 150 meters versus 43 centimeters, and readings are dependent on whale whims, but the information is invaluable.

"No one knew where blue whales went during winter," says Mate, "We tagged about a hundred, and now we know their fall migration, winter habitat and spring migration routes, too."

Another technology is bio-acoustics, which can be used without tranquilizing the animal —it just relies on the noises the animals make. Arrays of microphones record sounds and compare transmission times —like receivers compare GPS signals — and triangulate position and movement. Bio-acoustics can work even in deep jungles where the canopy blocks satellite transmission.

Privacy may be a thing of the past for elephants, but being under human's watchful eye might actually be life saving. Douglas-Hamilton has come up with an alternative to trophy hunting —green hunting. Hunters help tranquilize and collar elephants, then, instead of a getting a trophy on their wall they get daily Internet updates of their elephant's adventures. Good for the hunter, good for the elephant; even Lewis might not mind that kind of audience.

...there are probably 2,500 collars out in the wilderness, gathering data about critter liaison and dining out habits.

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