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The technology opened up a whole new way of interacting with the wild
world, and the Craigheads’ project—one of the first large-scale uses of radio
collars—signaled the birth of the modern era of wildlife tracking.*
Radio transmitters weren’t much use to the era’s marine biologists, in part
because radio waves don’t travel well through salt water. But these scientists
didn’t want to be left out of the tracking revolution that the Craigheads and
others were launching on land, and during the 1960s and ’70s, they started
developing their own instruments. The first attempts were slapdash; one
scientist measured the diving behavior of a Weddell seal with a pressure
gauge and a wind-up kitchen timer. But biologists and engineers stuck with it,
eventually creating devices that recorded information about marine mammals’
dives over the course of days and months. They also started following fish
using acoustic tags, which emitted sound waves that could be detected by
underwater microphones mounted to boats. The sound waves, alas, didn’t
travel very far, so scientists had to trail fish closely in order to stay in range.
Over the following decades, advances in computing made wildlife tags
smaller and more powerful. The development of satellite technology
presented exciting new options; tags that communicate with satellites allow
biologists to sit comfortably in their labs while zeroing in on a distant
animal’s exact location on the globe. We now have a burgeoning supply of
sophisticated electronic tags, some smaller than a jelly bean, that can keep
tabs on wild animals for months or years at a time. These devices are proving
to be especially valuable for learning about life in the ocean; marine
biologists can’t go sit in the middle of the sea and watch the fish stream by
the same way that Jane Goodall peered through the thick forests of Tanzania
to study her beloved chimps. By bolting a tracking device to a shark’s fin or
implanting one in a tuna’s belly, we landlubbers are gaining intimate access to
the lives of ocean animals.


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