In the WT's literature it is often theorised that the "great fish" that swallowed Jonah was a whale shark. Indeed looking at whale sharks with their wide huge mouths it seems reasonable to think that a human could fit in there...
... Until that is you do any research on it. While the whales mouth is huge, it's Oesophagus however is only a few inches wide. Nowhere near big enough to fit a human! For that matter the whale shark only feeds on small fare like plankton and small fish. It has 10 filter pads to make sure it can't swallow anything big.
It is easy to see how a primitive bronze age human could have seen one of these creatures and thought it could swollow them whole but with modern understanding we know that that isn't the case.
...just yet another gaping hole in the bible's stories!