Not all differences between species are apparent to the naked eye. Anyone can easily recognize members of the rabbit family, for example, for all species share obvious body similarities. Nonetheless, the family is split into two major groups not visible by appearance: the rabbits and the hares.
In the lowlands of the Chihuahuan Desert, we have the Desert cottontail--a rabbit--and the Black-tailed Jackrabbit—a hare. If you've been out in the desert much, you've probably seen both kinds and know that the jackrabbit is considerably bigger than the cottontail. That's not the important difference, however, and some kinds of hares look much like cottontails.
The division within the rabbit family is based on a major difference in
life histories. Hares are born ready to go, so to speak. Eyes and ears are open, fur is
in place, and the young are able to hop around soon after birth. The cottontails, on
the other hand, are born helpless, eyes and ears sealed, nestlings not ready to face
the world. As with people, looks often don't tell the story.
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.
Feldhamer, G. A., L. C. Drickamer, S. H. Vessey, and J. F. Merritt. 1999. Mammalogy. McGrawHill, Boston. 563 pp.