But was the ark big enough to hold the number of animals required?
The total available floor space on the ark would have been over 100,000 square feet, which would be more floor space than in 20 standard-sized basketball courts.
Assuming an 18-inch cubit [45.72 centimeters], Noah's Ark would have had a cubic volume equal to 569 modern railroad stock cars.
The total cubic volume would have been 1,518,000 cubic feet [462,686.4 cubic meters] --that would be equal to the capacity of 569 modern railroad stock cars.
Now comes the question, how many land dwelling air breathing animals would have had to be taken aboard the ark to survive the flood?
According to Ernest Mayr, America's leading taxonomist, there are over 1 million species of animals in the world.
God only provided the Ark for the protection of humans and land-dwelling, air-breathing creatures. A huge number of animals would not need to be taken aboard the Ark because they are water dwellers. Representatives would be expected to survive the catastrophe. With God's protection against extinction during the Deluge, survival would have been assured.
However, the vast majority of these are capable of surviving in water and would not need to be brought aboard the ark. Noah need make no provision for the 21,000 species of fish or the 1,700 tunicates (marine chordates like sea squirts) found throughout the seas of the world, or the 600 echinoderms including star fish and sea urchins, or the 107,000 mollusks such as mussels, clams and oysters, or the 10,000 coelenterates like corals and sea anemones, jelly fish and hydroids or the 5,000 species of sponges, or the 30,000 protozoans, the microscopic single-celled creatures.
In addition, some of the mammals are aquatic. For example, the whales, seals and porpoises. The amphibians need not all have been included, nor all the reptiles, such as sea turtles, and alligators. Moreover, a large number of the arthropods numbering 838,000 species, such as lobsters, shrimp, crabs and water fleas and barnacles are marine creatures. And the insect species among arthropoda are usually very small. Also, many of the 35,000 species of worms as well as many of the insects could have survived outside the Ark.