The animal in question is that which ruminates and be cloven-footed. Lev. 11:7 mentioned the swine as though with a divided hoof and cloven-footed yet, does not chew the cud, and so is unclean. And the hare cheweth the cud but divided not the hoof is unclean.
But the Bible is clear. It says the animal they should eat should chew the cud and have a cloven foot.
Let's consider the bat which is classified as a bird in the Bible. Some people pick quarrel with this saying, the bat is a mammal. But we know it was man that classified the bat as a mammal. At the time Bible was written, there was no biological classification. The Bible classified the bat as a bird because it has wings and can fly.
The main reason of calling an animal a mammal is the possession of mammary glands, and that it can suckle its young ones. Another factor is that it has hairs on its body. This is man's classification.