Which animal does Leviticus call unclean because, though it has a split hoof, it does not chew the cud?

Answer: The pig

Leviticus 11:7 says the pig has a split hoof but does not chew the cud, so it was unclean for Israel.

“And the pig, though it has a split hoof completely divided, does not chew the cud; it is unclean for you.”— Leviticus 11:7 (BSB)