Genesis 7:9

there went in two and two unto Noah into the ark, the male and the female, as God had commanded Noah. It was not a mere presentiment of coming danger that prompted the animals to gather about Noah, the clean and the unclean mammals, birds, and reptiles, neither was it a matter of instinct only, but it happened thus by God's arrangement, and it was He that commanded the animals to assemble at the place where the ark stood ready for occupancy. By pairs they entered into the ark under the direction of Noah, who thus fulfilled the command of God.