On British TV this week, marine biologist Monty Hall was diving with basking sharks off the coast of Ireland and only just managed to get out of the way of one that nearly caught him in its mouth.

What would happen if a diver - or any other large creature - swam into the path of a basking shark and went inside? Does the shark have some sort of gag reflex?

Not sure about a gag reflex, but anecdotally at least whale sharks are supposed to "cough" in order to clear their gill rakers of debris and it seems plausible that basking sharks might start coughing if a large object went into the mouth by accident.

It is obviously a hypothetical situation though. My hunch (and it is only that) is that a basking shark is actually very unlikely to swallow a large object in its path - it would much more likely avoid it or close its mouth. There are always photos of people swimming in front of big filter feeding sharks but no reliable reports of anyone being swallowed.

Last edited by Alistair Wilson (22nd Aug 2011 14:50:39)

If you did get swallowed by a whale-shark, might you be able to force yourself out through the gill slits?

I seem to recall that some people believe a whale-shark (which is bigger than a basking shark, right?) was responsible for Jonah's (Old Testament) plight! I see that Wikipedia quotes: "As for the whale shark, Dr. E. W. Gudger, an Honorary Associate in Ichthyology at the American Museum of Natural History, noted that "while the mouth is cavernous, the throat itself is only four inches wide and has a sharp elbow or bend behind the opening. This gullet would not permit the passage of a man's arm". In another publication he also noted that "the whale shark is not the fish that swallowed Jonah.""