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).
Note, however, that, as seen in the following drawings, the hyrax (on the left) and the rabbit (on the right), both exhibit crouched postures, just like the rat and the lizard15:
If being close to the ground was the trait used to distinguish the two classes of Land Animals from one another, the hyrax and hare would have been assigned to the Land Animals I taxon, along with the rat and the lizard. But they were not. Instead, they were assigned to the Land Animals II taxon along with the camel and the horse. Thus, being close to the ground was not the trait used to distinguish Land Animals I from Land Animals II.
In summary, no explanation has yet been given which explains how the Israelites distinguished Land Animals I from Land Animals II. An investigation of the issue is, therefore, warranted. This will consist of an analysis of the morphology and kinematics of Land Animals in order to determine what the Israelites saw that led them to differentiate Land Animals into these two classes.
IV. The Morphology of Legged Land Animals
Turning first to the morphology of legged Land Animals, vertebrate legged Land Animals exhibit one of two basic stances: the ‘sprawling’ stance and the ‘upright’ stance. These can be defined in the following manner:
...limbs with upright posture appear to extend straight down from the hip so that the foot appears to be directly beneath the hip. In contrast, for hindlimbs with typical sprawling posture, the femur is nearly parallel to the ground, the knee is lateral to the hip, the ankle is below the knee and, thus, the ankle and foot are lateral to the hip16.