How did all the animals fit into Noah's ark?

There are a few points that can help this issue make a little more sense.

• The Scripture says that Noah was to gather animals "after their kind". This implies that the animals brought may have been in the scientific classification of the family or even the order, rather than to the specific species or even sub-species. Take dogs for example. There are many kinds. It is entirely possible that one kind of dog was enough to save dogs from the flood. Also, the ancient peoples likely had a far less specific definition of species. In my opinion, this logic can be taken a step further to say that the evolution and differentiations of all the species out there is a Biblically sound concept.

  19 And of every living thing of all flesh, two of every sort shalt thou bring into the ark, to keep them alive with thee; they shall be male and female.
  20 Of fowls after their kind, and of cattle after their kind, of every creeping thing of the earth after his kind, two of every sort shall come unto thee, to keep them alive.
  21 And take thou unto thee of all food that is eaten, and thou shalt gather it to thee; and it shall be for food for thee, and for them.

• The maturity of the animals taken was not specified. Noah could have taken babies, eggs, or the otherwise smaller, infant versions. The benefits are obvious. Noah would certainly prefer the baby 200 pound elephants over the mature 7 ton adults.

• The quality of the food brought was not specified, nor was the amount (ration) eaten each day. Most animals can eat sparingly for a few months and still survive. Considering the animals would be stuck on the ark and unable to exercise they would likely use less calories, therefore require less food to survive. The point is that the ark was for survival. It was not a luxury cruise.

• Water was certainly not an issue. It was a flood; there was plenty to go around.

As for your other questions: Yes, God intervenes and did then too. The flood came because God made it so. The Ark survived because God made it so.

Noah was not tasked with taking every single species on the whole planet. If you look at the animals that were taken in Genesis 6, they are all vertebrates. Vertebrates only compose about 3% of all the animal species in the world. How Many Animal Species Inhabit Our Planet?

Of this 3%, there were NO water dwelling species taken. Of that fraction, only KINDS of animals were taken (Gen. 6:20) – because animal species are grouped into kinds called genera: “Genera: The usual major subdivision of a family or subfamily in the classification of organisms, usually consisting of more than one species

Animals on the Ark:

“There are currently 1,260 genera, 156 families, 29 orders, and exactly 5,877 species of described mammal, all in a single class.” Estimated Number of Animal and Plant Species

Land Mammals: Total Mammal Genera: 1,260 - about a third clean (approx. 416 clean) = total of 2,912 animals - about two thirds unclean (approx. 844 unclean) = total of 1,688 animals

Total land mammals = 4,600 approx

(the following numbers based on species Genera information derived from Wikipedia)

Birds: Total Bird Genera: approx. 1,627 - about a third clean (approx. 542) by seven’s = 3,794 clean birds - about two thirds unclean (approx. 1085) by two’s = 2,170 unclean birds

Total birds = 5,964 approx.

Reptiles and Amphibians: Reptile genera – approx. 175 genera (none clean) Amphibians – approx. 86 genera (none clean) Total = 261 Genera

Total Reptiles and Amphibians = 522 approx.

Insects: Ant genera‎: 374, Beetle genera: ‎ 437, Hymenoptera genera: 55, Lepidoptera genera‎: 3, Moth Genera: 66, Monotypic insect genera: 76, Other Insect Genera: 30, Extinct Insect genera: 104 Total Insect Genera = 1,145

Total Insects = at least 2,290 (Likely much more)

Dinosaurs: Dinosaur genera: about 300 (none clean) How many types of dinosaurs are known?

Total Dinosaurs = 600

There were an unknown number of Genera (including dinosaurs) of all creatures that are nowadays extinct but were on board Noah’s Ark. Let’s assume that about 10% of these creature genera are now extinct:

Mammals: 126 extinct genera - a third (42) clean by sevens (total = 294), two thirds (84) unclean by twos (total = 168). Possible total of Now Extinct mammals on Noah’s Ark = 462

Birds: 163 extinct genera (a third (54) clean by sevens = 378 birds and two thirds (109) unclean by two = 218 birds. Possible Total of Now Extinct Birds on Noah’s Ark = 596

Reptiles and Amphibians 20 extinct genera (all by twos) Possible Total of Now extinct Reptiles and Amphibians on Noah’s Ark = 40

Possible Complete Total of extinct Genera = 1,643 creatures and 728 insects

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Total animals on Ark – estimated: 13,329 – 14,000

• with at least an additional 2,290 insects (probably many more).**

**

Could all these creatures fit in the Ark?

Genesis 6:15 - "The ark is to be three hundred cubits long, fifty cubits wide and thirty cubits high."

Royal cubit being used here is well known as being 20.62 inches, examples of cubit rods can be seen in British museum and Louvre, France. Measurement system (Encyclopedia Britannica).

• Ark Length = 300 Cubits (157.14 meters) (515.58 feet)
• Ark Height = 30 Cubits (15.71 meters) (51.56 feet)
• Ark Width = 50 cubits (26.19 meters) (85.93 feet)
• Ark: 15,000 square cubits per floor (44,303.79 square feet)
• 3 floors = (44,303.79x3)

Ark’s total floor space = 132,911.37 square feet (about 2.3 standard American football fields).

The land mammals that were taken on board would have been young ones just entering or nearing the beginning of their breeding cycle – not the fully grown adults.

Birds take up very little space and were all kept in small cages or aviaries. Many types of birds have no problem living in the same place. Birds were represented in the most numbers on the Ark with 38% of all the animals being birds compared to 17% mammals.

The reptiles and amphibians are likewise very small and could be kept in small enclosures that could even be stacked on top of each other as the ark had a very high floor height.

The insects themselves would have taken up very little room also and could have been protected in little enclosures. Many other insects and eggs would naturally have come in with the food and animals.

It is estimated that these animals would only take up about 47% of the available space on the Ark leaving PLEANTY of room for food, water and other supplies.

There are assumptions that everybody makes when hearing about this story, so let's take another look at this specific verse in order to drop those assumptions.

Genesis 6 NKJV

19 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.

This passage says take two of every SORT, the NIV says take two of every KIND. It's clear that there were not 4 dogs on the ark, but only two dogs. We assume today that all dogs evolved from wolves. It's possible that only wolves had been taken onto the ark.

Also keep in mind that a logical person is not going to take two full size elephants onto the ark. Instead, they'll take babies. Babies are healthier, they will live longer and more of an opportunity to breed more of their kind.

There are only 2000 different TYPES of animal species on this planet. Let's be safe and double that number because some (dinosaurs) could have gone extinct. So 4000 species, and then double that number again because we're taking two of each. So we're at 8,0000 different kinds of animals on the ark.

According to the sizes given the ark would have been over 100,000 square feet. Enough room to house 16,000 animals plus food and water supplies for twelve months.

The group "Answers in Genesis" will point out that the scripture is not bound by our understanding of species, but rather states the he should bring every "kind" or "sort" of animal. That is, rather than bring a cheetah, jaguar, lion, tiger, panther, leopard, puma, etc., he could have brought some sort of cat, and further speciation would have taken place after the fact. This understanding would vastly cut down on the number of animals required from millions to thousands.

The other possible answer, one that most Christians would likely not accept is that the flood was not as global as assumed. The events of the flood predate the Tower of Babel, which is when humanity is said to have been scattered across the globe. So one could assume that the human population was very localized.

God would not need to flood the entire planet to wipe out humanity. It would be more logical to just flood the region where humans resided and not have to worry about getting every species onto a wooden ship.

So then Noah could focus on getting local wildlife that shared the region with humans onto the ship.

Someone in another answer mentioned the stability of a wooden vessel of this size. I don't see that as being a tremendous problem as:

1. it was a one-time use vessel
2. God probably wouldn't let it sink.

Yes, biologists have identified about 1.4 million species. There are surely other species not yet identified and cataloged, but estimates vary widely on how many. I've seen estimates for total number of species ranging from less than 2 million to over 100 million.

But the majority of species are microscopic. By definition, microscopic creatures would not take up any measurable amount of space on the ark. They would have just been carried along in or on the larger creatures.

The International Union for Conservation of Nature -- no indication they're a Christian or creationist group, they're environmentalists -- estimates there are 1.3 million non-microscopic creatures in the world. You can get similar numbers in many places. Anyway, 1.3 million, still a lot. But 1,000,000 of those are insects and another 102,000 are arachnids, which don't take much space. 31,000 are fish. The salt-water fish, at least, would not have had to be carried on the ark: Noah didn't need to build fish tanks. Another 85,000 are mollusks, most of which are sea creatures. The only creatures Noah would have had to worry about are what's left: 5,490 species of mammals, 9,998 birds, 9,084 reptiles, and 6,433 amphibians. That makes 31,005 species. (See International Union for Conservation of Nature Red List, Gland, Switzerland, 2010, Table 1.) (And by the way, I'm just using them as a convenient source. You can find similar numbers from other sources.)

As others have noted, Genesis says Noah brought 2 of each "kind", not 2 of each "species". A baramin (kind) is usually broader than a species. So 31,000 is pretty much the upper limit.

So Noah would have had to bring 31,005 x 2 = 62,010 animals. (Okay, a little more for the creatures that he brought 7 pairs.) There are and were certainly some large animals in the world --hippos and elephants and allosauruses and so forth -- but most species are much smaller than this. The average animal weighs about 100 grams, about the size of a large rat.

John Woodmorape wrote a book called "Noah's Ark: A Feasibility Study" in which he devotes considerable space to calculations on how much space would be required. He comes up with a total of 15,754 animals. (i.e. he's counting baramin and not species.) He then estimates space requirements by using the amount of space given to animals in laboratories and factory farms. He makes the argument -- a valid one, I think -- that this is a good "middle number". Using the space given when transporting animals in trucks, train, or plains would be too small: such trips tend to be short, so the animals don't need a lot of room. But using space given in zoos would be too large: Zoos are meant to be comforable, and the environments are as much to entertain the visitors as to be pleasant for the animals. The Ark voyage was not a pleasure cruise. So anyway, using figures for space in labs and factory farms, he came up with a total space requirement of 4,300 square meters. That is less than half the floor space on the ark if built to the dimensions in Genesis. That's a high number, because it assumes all cages sit on the floor, but surely Noah could have stacked the cages of the smaller animals.

Woodmorape goes on to calculate that food for the voyage would have taken another 6 to 12% of the available space. If they had to bring along enough water for the entire voyage, that's another 9%. (In real life they could likely have captured rain water to meet at least some of their needs.)

So, as I say in my book, all the animals plus the food and water would have taken up about 2 of the ark's 3 decks. That leaves the other deck for quarters for Noah and his family, room for extinct animals unknown to us today, the dance floor, casino, and karaoke bar.

There are several factors that allows this. One of this, is the sheer size of the ark. According to the dimensions that the Bible gives, the Ark will have

Thus, the ark could have been up to 550 feet long, 91.7 feet wide and 55 feet high. These are not unreasonable dimensions. But how much storage space does this amount to? Well, 550 x 91.7 x 55 = 2,773,925 cubic feet.

That's the amount of space available. That's approximately, 522 railroad cars, each carrying 240 sheep.

But what about all those large animals, the elephants, mammoths, dinosaurs?

The answer is, Noah could easily have taken the infants of these large animals. Even if he didn't, a proffessor estimated that:

John Woodmorappe, author of the definitive Noah's Ark: A Feasibility Study, estimated that only about 15% of the animals on the ark would have been larger than a sheep. This figure does not take into account the possibility that God may have brought Noah “infant” animals, which can be significantly smaller than adult animals.

Even with all those large animals, there would still have been ample space:

...it has been calculated that a little more than half (54.75%) of the 2,773,925 cubic feet could store 125,000 sheep-sized animals, leaving over 1.5 million cubic feet of free space (see - http://www.icr.org/bible/bhta42.html).

Now concerning the sheer number of species, there is quite a simple explanation. Purmou has already taken that into consideration, and I would like to use an example:

In today's world, there are about 400 different types of dogs. But, they all have one common ancestor, the wolf. The way these dogs have been bred, is through the elucidation of certain DNA, so that only desired characteristics remained, and the DNA that isn't needed is not in these dogs. Basically, a loss of DNA.

Links : How did Noah fit all the animals on the Ark?

I suppose there is one other possible answer:

It was a miracle.

That would put it in the "how did Jesus walk on water?" and "how did Jesus feed thousands of people with a few fish sandwiches?" category.