Malbim: Predatory animals, which normally harm for their benefit.

Malbim: Snakes, which normally destroy without benefit.

Radak: All of Eretz Yisrael is called so, because it is higher than all lands.

Radak: Yes. They will not harm, because the land, i.e. Eretz Yisrael, will be full of knowledge of Hashem - "Ki Chulam Yad'u Osi lemi'Ktanam v'Ad Gedolam" (Yirmeyah 31:33).

Malbim: It is a metaphor. Recognition of Hashem will spread so much that even predatory animals will recognize that the time for fixing came, even though they do not have intellect.

Rashi: It is to know Hashem.

Bava Basra 74b: Hashem killed the Sar of (angel appointed over) the sea for refusing to do His command. If the water would not cover it, no creature could stand its smell , we read "la'Yam Mechasim" like 'l'Sarah Shel Yam Mechasim.'

Radak: The place of the water is called Yam. Water fills that place until it covers it, so the floor of the sea is not seen.

Malbim: Just like nothing holds back water from covering it, so the physicality of animals, which is not prepared for understanding, will not block knowledge of Hashem that will spread over all flesh. This refers to the change in animals' nature, based on Hashem's word.