For decades, the US Navy has had a crack team of highly intelligent (and very cute) dolphins swimming around, trained to find naval mines before they blow up something big and expensive. Now, though, their time has come: like a naval Batman at the end of a fishy version of The Dark Knight, they're no longer needed.

The dolphins are being replaced by a 12-foot robot called the KnifeFish, which can apparently do many of the same things. Can it really, though? The list of things that the dolphins can do is extraordinary: they can not only detect sea mines and mark them with buoys, but also swim down unauthorised swimmers in restricted areas, and fix lines onto objects to help recover them. Not to mention, they're adorable.

At least the dolphins aren't being totally axed -- no under-appreciated mammals limping round the Pacific on a measly pension. They're being brought back to the US, where they'll join sea lions on harbour defence duty. Personally, given how much fun it is to swim with dolphins, I'm not sure how good they'll be at dissuading people from swimming into places they're not meant to be in -- maybe some US Navy great white sharks would be more effective in this department?

So, question: if the dolphins weren't used to guard harbours, what should they be used for? Imagine, for a second, that you're a super-squillionaire with a pack of highly-trained dolphins at your disposal -- what would you do with them? [Guardian]

Image credit: US Navy