If you've ever seen a mole, with its virtually useless minute eyes, you might take pity for an animal unable to share the magnificent vistas that we usually take for granted. Yet, most mammals and many invertebrate animals might just as well shed a few tears for our blindness—not a blindness of sight but to the joys of smells and other chemical stimuli.
Ever wonder how ants follow an invisible trail, traveling in lines as
circumscribed as any hoard of city dwellers confined to a sidewalk? Watch carefully,
and you'll often see corrective maneuvers as individuals starting to wander off the
edge of their hidden sidewalk veer back to the center. They simply are following a
trail of chemicals laid down by other ants—a trail as clear to them as a highway to us,
though without the distant vision we enjoy. Want to see them go temporarily blind?
Remove a leaf or stone from their pathway, a showstopper until their search pattern
locates the far end of the broken link, and new chemicals bridge the gap.
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.