How could Noah get all the animals on the Ark?
Skeptics often toss this challenge out, thinking there is no answer, but there is, and a simple one at that.
There are two parts to the question—the number of animals, and the size of the Ark.
Every species of living creature did not need to go on board. Only the animals that were air breathing (‘all flesh in which there is the breath of life’ (Genesis 7:15)) and land dwelling (‘all flesh died that moved on the earth’ (Genesis 7:21)).
So fish did not go on; they are not air-breathing. Whales and dolphins did not go on either. Although they breathe air, they are not land-dwelling. Fish and whales survive under water, although some die during floods when sediment and other debris contaminate the water. We find many marine fossils that were buried during the Flood.
Insects were probably not collected and housed on the Ark. They do not have nostrils (Genesis 7:22) to breathe air, and can survive floods on floating debris such as vegetation mats. No doubt many insects hopped on board anyway.
So, that reduces the number of species. But how many animals?
Take dogs, for example—would Noah have taken two Alsatians, two cocker spaniels, two collies, two red setters, etc.? No, he would have needed just one pair of dogs, like the wolf kind, with much genetic variation, somewhat like mongrels today. We know that the different breeds of dogs have been produced from a wolf-like dog, and this only took a few thousand years. That is not evolution; that’s just variation within the original created kind.1
So we have many more different kinds of animals today than Noah took on the Ark. They have diversified in the 4,500 years since the Flood. The actual number of animals Noah put on board depends on what a biblical ‘kind’ is.
Woodmorappe in his book Noah’s Ark: A Feasibility Study calculated that the number of animals would have been less than 16,000, assuming that a biblical kind is roughly equivalent to the group of animals we call a genus today. However, if the biblical kind is equivalent to the ‘family’ grouping, then there would have only been 2,000 animals. Probably it was somewhere in between.
The animals would have been easily housed in small enclosures because most animals are small, on average the size of a rabbit. Even large animals, such as the biggest dinosaurs, began their lives small. In selecting creatures to repopulate the earth, it would make more sense to choose those that were young and healthy, rather than the older, mature ones.
And the size of the Ark? It was huge. It had a capacity of over 500 railroad stock cars, enough to carry more than 120,000 sheep. So there was plenty of room on the Ark for the animals, for their food and water, and for Noah and his family.