Leviticus 11:24, 43-44

And by these ye shall become unclean: whosoever toucheth the carcass of them shall be unclean until the even

Ye shall not make yourselves abominable with any creeping thing that creepeth, neither shall ye make yourselves unclean with them, that ye should be defiled thereby. For I am Jehovah your God: sanctify yourselves therefore, and be ye holy; for I am holy: neither shall ye defile yourselves with any manner of creeping thing that moveth upon the earth.