Clean And Unclean Animals

Genesis 1:31 declares that all of God's creation is good, animals included.  A creature does not have to possess the image of God as humans are said to (Genesis 1:26-27) in order to have value grounded in the uncaused cause as well.  Some creatures could be higher and still everything created as it was by a morally perfect deity would have some level of baseline moral value.  Deuteronomy 22:1-3, 6-7, Jonah 4:10-11, Proverbs 12:10, Numbers 22:21-33 (Balaam's donkey being given speech would imply that it already had thoughts, which require consciousness), and so on elaborate on some of the obligations to animals, which are to be recognized and treated as lesser creations but still as having certain rights.  That Yahweh affirms their deaths as a weighty factor in the destruction of Nineveh alone, as do any of these other verses, affirms this.

Even so, entire categories of animals are unclean in Biblical theology, such as animals with cloven hoofs that do not chew their cud (see pigs, which are mentioned in Leviticus 11:7) or fish or other aquatic beasts that do not have both fins and scales (11:9-12).  These are to not be consumed along with other kinds of meat, such as that of cows or salmon.  Specific birds like eagles and vultures are unclean (11:13-19).  Other than locusts, katydids, crickets, and grasshoppers, all insects with wings that walk on four legs are also unclean (11:20-23).  Then there are additional comments about animals on the surface of the ground like rats and monitor lizards being unclean while living and thus unfit for eating (11:29-31, 41-42).  Mosaic Law is fairly precise with the exact divisions between clean or unclean animals.

What the Torah means by an animal being unclean, though, does not entail that the animal has no value at all as a living thing that still in some way would reflect Yahweh as the metaphysical source of life, albeit to a much smaller extent than a human.  Even kosher animals make someone unclean until evening when the corpse is touched (11:39-40), but this does not mean that a person loses the image of God until that time of day!  It is not even that touching the carcass is sinful (Deuteronomy 4:2).  Eating unclean animals, not the bodies of dead clean animals, is what is prohibited.  Unclean animals are not worthless on the Christian worldview.  They are simply unclean for consumption and physically contacting their dead bodies makes someone unclean until evening.

Genesis 1 already addresses the foundations of many philosophical issues related to Biblical morality, including the fact that animals would also have value as "very good" creations of God (and this means that even as herbivores, animals would eaten living things, so death of some kinds was originally intended).  That some are unclean is not the same as them deserving to be abused or entirely shunned.  They are not to be eaten, and they still have some degree of goodness as things that God directly created or permitted to come into being.  Non-human animals--yes, humans are biological creatures, aka animals as well, just a very different kind as far as outward evidences indicate--are not Biblically unclean in the sense of being worthless or having no moral rights at all.