Genesis 7:2-3, 8-9

You shall take with you of every clean animal by sevens, a male and his female; and of the animals that are not clean two, a male and his female; also of the birds of the sky, by sevens, male and female, to keep offspring alive on the face of all the earth.

Of clean animals and animals that are not clean and birds and everything that creeps on the ground, there went into the ark to Noah by twos, male and female, as God had commanded Noah.