We're used to the idea of obsolescence and replacement. New models of automobiles, changing fads of style, the unrelenting flood of software version after software version. Indeed, perhaps some of us measure the passage of time by change. But there's an idea foreign to many of us—that of finding something that works and holding on to it with a death grip. Unprogressive? Unimaginative? Almost un-American? Sure, but it's said that only a fool argues with success. One such success is an animal who has changed very little over more than 60 million years—the Virginia Opossum.
This marsupial of South American lineage does well in eastern North
America—even when northern populations have frost-bitten tails and ears to show for it.
However, the dry lands of the Great Plains and the Southwestern deserts have been a
challenge. Nevertheless, possibly aided by human hands, these creatures have managed to
gain a toe-hold in those Southwestern linear oases that we call river valleys. And with
that toe-hold, they've done what they've done for millions upon millions of
years—survive!
Contributor: Arthur H. Harris, Laboratory for Environmental Biology, Centennial Museum, University of Texas at El Paso.
Desert Diary is a joint production of the Centennial Museum and KTEP National Public Radio at the University of Texas at El Paso.