All Creeping Things Are Unclean Especially When Dead (Leviticus 11:29-31).
“And these are they which are unclean to you among the creeping things that creep on the earth; the weasel, and the rat, and the great lizard after its kind, and the gecko, and the land-crocodile, and the lizard, and the sand-lizard, and the chameleon. These are they which are unclean to you among all that creep. Whoever touches them when they are dead, shall be unclean until the even.”
The same principle applied to all small rodents and reptiles. They were unclean and must not be eaten, nor must their dead bodies be touched. The very fact that they are called ‘creeping things' links them with the snake. Instead of running freely among the beasts they share their environment with the creature that brought about man's downfall. If they were touched then the person was again unclean until the evening. They were defiled. They must not go to the tabernacle or eat of holy meat. We are not absolutely certain of the identification of each Hebrew word describing these creatures, but the general pattern is clear.
We note that there is no mention of a remedy in washing. Thus the idea is that, apart from contact with clothes, any ‘uncleanness' will rub off during the day, with time. All these are to be seen as untouchables. They are not of the kind which should be of interest to the people of God, but should be avoided.
Once again the rules, if faithfully observed, would have saved the Israelites from much disease, and we cannot really doubt now that ideas of defilement and disease were seen together as uncleanness. They could hardly avoid noticing cases where contact with such dead creatures sometimes resulted in various forms of disease, even if they did think of it as a judgment for touching what was unclean. But from the point of view of the Israelites, by avoiding these things they were pleasing Yahweh and doing His will, and showing themselves to be His people. They were avoiding what was unseemly.
With regard to hygiene the very distinctive regulations that follow must surely have hygiene in mind, for had it been simply a matter of ritual uncleanness the distinctions would surely not be made. But it is dressed up in terms of uncleanness and to give the people a horror of the unseemly.