Was it a Whale or Just a "Big Fish" that Swallowed Jonah? (And Why Does It Matter?)

For some reason, skeptics seem obsessed with the story of Jonah and the whale.Even 
during the Scopes Trial, Defense Attorney Darrow asked Prosecutor Bryan if he really 
believed that a whale swallowed Jonah. Bryan corrected Darrow by saying the King 
James Version uses the term "big fish" and not "whale." This debate continues today. 
Was it really a whale which swallowed Jonah or just a big fish.

The Hebrew word used in Jonah is the word "dag" which just means fish regardless of 
size. When the Hebrew was translated into Greek, though, the word "ketos" was used. 
Ketos means "large fish" in Greek. This is also the word translated "whale" in the KJV of 
Matthew 12:40 when Jesus gives an account of Jonah. This is where the skeptics point 
out that the Bible is contradictory because, after all, a whale is not a fish; it is a mammal. 
Therefore, Jonah and Matthew can't both be right.

We must remember, though, that the only reason a whale is a mammal is because 
people say so. The modern system of taxonomy, or classifying living things into groups, 
was invented by people relatively recently. When the system was devised, whales were 
put into the mammal group because they share some characteristics with other animals 
in the group. They breathe oxygen, have hair, give birth to live young etc.. If other 
characteristics were used to classify, the whale could have been put into the fish group. 
It has fins, lives in the water etc.. In fact, to the ancients, including Jonah and Matthew, a 
whale was a fish. This doesn't mean they were wrong, they just used a different 
classification system.

Overall, it doesn't really matter whether the big fish that swallowed Jonah was a whale or 
not. The real question is was it a real occurrence or just an allegory. The Bible treats it 
as a real event. Jesus treated it as a real event comparing it to his own death. So, we 
should treat it as a real event.