In P's account, therefore, Noah did not perform a sacrifice, and only two of each animal were required. The only problem I had in reading the book was that it was sometimes hard to keep track of the global picture of who wrote what and when. In Gilgamesh, Utnapishtim loads his boat with animals and posessions. The animals of the fields, wild beasts of the fields, the children of all the craftsmen I drove aboard. And of all the living, of all flesh, you shall bring two to the ark to keep alive with you, and they shall be male and female.
Genesis shows equal confusion over the length of the flood.
On the seventh day of its coming the stormflood broke from the battle which had labored like a woman giving birth. I looked out at the day. Stillness had settled in. All of humanity was turned to clay. The ground was like a great, flat, roof.