| MadSci Network: Zoology |
Interestingly (to me anyway) both words, equus and caballus, are Latin for "horse". Apparently, "caball" was a more dialectic term than "equus", that is, it was not as widely used by Latin speakers, so it lost out for genus name. As a genus name, Equus alone is used to refer to horses and all of their relatives, including donkeys (Equus asinus), three kinds of zebras (Equus burchelli, Equus grevyi, and Equus zebra), and wild Asian horses (Equus hemionus).
Try the links in the MadSci Library for more information on Zoology.