The Old World and New World have passed back and forth animals and plants since first European contact. Some exchanges have proved highly beneficial, such as wheat and rice to the New World and corn and tomatoes to the Old. Other occurrences, though, seem better described as invasions and, in the New World, include three species of rodents, the House Mouse, the Norway Rat, and the Black Rat. The Norway Rat is acclimated to cooler climates, but the Black Rat does well in the cities and farms of the Chihuahuan Desert region.
The latter also is known as the Roof Rat. That name is instructive,
because these are excellent climbers and thoroughly at home on beams, electrical
conduits, and other aerial pathways. The Black Rat likely was responsible for spreading
the fleas carrying bubonic plague during the Middle Ages in Europe and the Near East.
Up to a third of the population of Europe is estimated to have succumbed. In the
Southwest, however, most plague is carried by native rodents, while Black Rat damage is
mainly to property.
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.