Sometimes, related species are easy to tell apart. Who could mistake a lion for a tiger? It isn't always that easy, though, because quite often different kinds look very similar. And the problem is further compounded by us grouping a number of species under a single common name, as if they were all one. For example, how often do we hear people talk of "the bat" or "the mouse"? Locally, we hear people talk about "the kangaroo rat", perhaps not realizing that we have three northern Chihuahuan Desert species.
When you actually look at them, though, it's clear that there are larger and
smaller ones. The Banner-tailed Kangaroo Rat is large, with a white-tipped tail.
Biologists know that there are two kinds within the smaller rats, but John Doe would
have trouble telling them apart. If in hand, there is one tell-tale sign—Merriam's
Kangaroo Rat has but four toes on the hind foot, while Ord's Kangaroo Rat has a
small fifth toe halfway up the foot. We may have difficulty telling them apart, but
they have no trouble whatever!
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.