Richard Whitekettle, «Rats are Like Snakes, and Hares are Like Goats: A Study in Israelite Land Animal Taxonomy», Vol. 82 (2001) 345-362
Israelite taxonomic thought drew a contrast between a land animal taxon referred to by the words Cr#$ or #&mr that contained animals such as rats and snakes (Land Animals I), and a land animal taxon referred to by the words hmhb or hyx that contained animals such as hares and goats (Land Animals II). This essay shows that the Land Animals I taxon was characterized by locomotory movement in the horizontal plane and the Land Animals II taxon was characterized by locomotory movement in the vertical plane. Thus, the contrast was between land animals that were perceived to move along the ground (Land Animals I) and land animals that were perceived to move over the ground (Land Animals II).
Land Animals that have an upright stance exhibit various bodily movements during locomotion which are vertical in orientation. Such movements include the dorsoventral bending of the trunk, other dorsoventral movements (such as neck/head movement), or vertical fluctuations in an animal’s center of gravity, which occur as the animal propels itself over the ground27. This can be seen in the following lateral views of a horse (on left) and cheetah (on right)28: