The transition from land to sea dates to about 49 million years ago, with the "Ambulocetus" ("running whale"), discovered in Pakistan. It was up to long. The limbs of this archaeocete were leg-like, but it was already fully aquatic, indicating that a switch to a lifestyle independent from land happened extraordinarily quickly. The snout was elongated with overhead nostrils and eyes. The tail was strong and supported movement through water. "Ambulocetus" probably lived in mangroves in brackish water and fed in the riparian zone as a predator of fish and other vertebrates.