There are modern examples of people being swallowed by whales and recovered alive.
Reliable citation needed.
My research show no such thing. There are two old stories, one from a passenger on The Star of the East, back in the 1890's that's been discounted, and several from the whalers in New England (New Bedford holds most of the ship logs from that period) who talk about people being in the closed mouth (but not swallowed), and even being chewed, and surviving (albeit with missing parts).
First there is only one species of whale that could swallow a man whole, that's a sperm whale (and they are not commonly found in the Med). Now Jonah is going to have to make it past the jaws (about 30 feet) that are lined with 8 inch teeth without being chewed - because pretty much one chomp from a 15 ton animal with 8 inch teeth is going to do you in. Then your going to have to go through the digestive tract (only a sperm whale has one large enough for a man to fit through, this has been well-researched by people attempting at the time - 19th Century - in an attempt to prove the Bible story true) to end up in an airless chamber of digestive acids and water , for 72 hours - then you're going to have to come back the other way. And...and...and - all without panicking to the point of extreme shock that you would die of a heart attack,* which BTW is a natural protection mechanism in most mammals to prevent them from having to experience things exactly like this, say with a boa.
19th Century scientists and archaeologists went to great lengths to try to use modern scientific evidence and methods to true the Bible stories (and other ancient myths/legends/stories/tales) and had much success. (parting of the Red Sea, the story of Jericho, the existence of Troy) But they also managed to conclusively prove that some of those stories could not have happened in the way the book recounts - as with Jonah and the belly of the whale.
* - about half the people who jump from the Golden Gate Bridge are not killed by the fall (220 ft. ave.) but die on the way down of a panic-induced heart-attack.