How could Noah fit all of the animals onto the Ark? How is it possible that they could all have survived for 40 days and 40 nights? How did Noah do this?
The Great Ark
Most people might not realize the incredible size of the ark built by Noah . I believe that the Ark was built big enough not only for each of two kinds of animals to fit in to but also had room for anyone who would repent and trust in God and come aboard the ark and be saved. According to the dimensions given in the Bible and translating cubits into feet, the ark could well have been over 500 feet long, almost 92 feet wide and 55 feet tall. The length of the ark then would be over 1 & ½ football fields. The ark’s total square feet available was anywhere from 2 to 3 million square feet! The ark also had three levels or floors in it and dozens of compartments to accommodate the different types and sizes of animals on board.
In the book, Noah’s Ark: A Feasibility Study by John Woodmorappe, he estimates that around 15% of the animals on the ark would have been larger than a sheep . When God directed two kinds of each animal to go onto the ark, they may have been infants. That is, these animals could have been the very young, thus making it easier for all of these to fit onto the ark. Many animals, perhaps even some dinosaurs , were not directed to board the ark and thus may have drowned and become extinct in the flood. There is strong fossil evidence that the earth was covered by water at one time and that many species did not survive this flood. These animals may have been allowed to be wiped out because they were not necessarily beneficial to mankind as Noah and his family repopulated the earth. Whales, fish, clams, and other sea creatures had no need for shelter and simply survived in the oceans without any need of the ark.
What Went onto the Ark?
In Genesis chapter 6 we see what animals went onto the ark; “And of every living thing of all flesh, you shall bring two of every sort into the ark to keep them alive with you. They shall be male and female. Of the birds according to their kinds, and of the animals according to their kinds, of every creeping thing of the ground, according to its kind, two of every sort shall come in to you to keep them alive. Also take with you every sort of food that is eaten, and store it up. It shall serve as food for you and for them” (Genesis 6:19-21). God also told Noah to bring into the ark, “seven pairs of all clean animals, the male and his mate, and a pair of the animals that are not clean, the male and his mate, and seven pairs of the birds of the heavens also, male and female, to keep their offspring alive on the face of all the earth” (Genesis 7:1-3) and “every beast, according to its kind, and all the livestock according to their kinds, and every creeping thing that creeps on the earth, according to its kind, and every bird, according to its kind, every winged creature. They went into the ark with Noah, two and two of all flesh in which there was the breath of life. And those that entered, male and female of all flesh, went in as God had commanded him” (Genesis 7:14-16).
So every species that would survive the flood was brought into the ark and again these may have been the very young. Also, every type of provision like water and food was brought onto the ark to ensure that the animals and Noah’s family was to survive as God commanded Noah to “take with you every sort of food that is eaten, and store it up. It shall serve as food for you and for them” (Genesis 6:21).
The Analogy of the Ark as Salvation
Genesis 7:16c indicated that it was “the Lord [who] shut [Noah] in.” The analogy is that it is the Lord Himself that does the saving. The ark was covered with pitch to protect against the waters of the flood. The word “pitch” in Hebrew is kopher, sometimes spelled kophar, which means “atonement” or “covering.” The symbolism is perfect for God Himself, in Jesus Christ, became our covering or our atonement. The flood is seen as a type of baptism for Noah and his family but the floods are symbolic of God’s judgment on sinners. The ark is a picture of God’s process of salvation. Anyone who chooses to come will be saved and the ark [Christ] is the only possible escape from death. And there was only one door into which to enter the ark, which reminds me of what Christ said, “I am the door of the sheep” (John 10:7) and “he who enters by the door is the shepherd of the sheep” (John 10:2), thus there is only one way to be saved (Acts 4:12). The Lord God Himself not only closes the door, but seals it, which seems to be indicative of the sealing by God the Holy Spirit which Paul writes about in Ephesians 1:13b that you “were sealed with the promised Holy Spirit.” Noah could no more have shut the door and sealed it than we can save ourselves.
The ark reminds us that we are saved by faith and not by works because by “faith Noah, being warned by God concerning events as yet unseen, in reverent fear constructed an ark for the saving of his household. By this he condemned the world and became an heir of the righteousness that comes by faith” (Hebrews 11:7) but Noah is also a reminder that “if [God] did not spare the ancient world, but preserved Noah, a herald of righteousness, with seven others, when he brought a flood upon the world of the ungodly,” (2 Peter 2:5) likewise God will also punish all who refuse to come to him. God truly desires to save those who are presently lost.
God is patient but we must choose today to be saved for this is the day of salvation. Noah preached for 120 years because God desires that none should perish (2 Peter 3:9) and He is longsuffering. We base this number of years Noah preached from the fact that he was 600 years old  at the time of the flood and he would have started preaching at age 480 but the point is, even God may decide that the sinner’s time is up (Genesis 6:5) so “now is the favorable time; behold, now is the day of salvation” (2 Corinthians 6:b). We don’t know if we will live beyond tonight or tomorrow so I plead with you to not put off the opportunity for eternal life today. James warned us to not say, “Today or tomorrow we will go to such and such a city, spend a year there, buy and sell, and make a profit”; whereas you do not know what will happen tomorrow. For what is your life? It is even a vapor that appears for a little time and then vanishes away” (James 4:13-14). So my advice is that “Today, if you hear his voice, do not harden your hearts” (Hebrews 3:15) because if you die without Christ, you will live with eternal regret and that would grieve the heart of God.
Read more about Noah and the Ark here:
Resources – New International Version Bible (NIV) THE HOLY BIBLE, NEW INTERNATIONAL VERSION®, NIV® Copyright © 1973, 1978, 1984, 2011 by Biblica, Inc.™ Used by permission. All rights reserved worldwide.  Woodmorappe, John, Noah’s Ark: A Feasibility Study. Institute for Creation Research. July, 1996. ISBN-10 0932766412