Whatever, Ukraine. Your claims of arming a fleet of dolphins with pistols and knives are dubious. This is why you can't transform man's favorite adorable aquatic buddy into sea mammals of death.

Dolphins are fantastic, intelligent creatures. They've got a sensing ability, echolocation, that's akin to "natural biological sonar," as Ed Budzyna of the U.S. Navy Marine Mammal Program puts it. Yes, as we've reported in the past, the Navy trains dolphins and sea lions for harbor and port security tasks that nature has endowed them well to perform.

Those tasks are not attack tasks. And yet, a story has resurfaced that the Ukranian Navy has strapped its military working dolphins with knives and pistols to their heads. It smelled funny to us the first time we encountered it in the fall. This time around, the allegedly-armed Ukranian dolphins have apparently gone rogue, swimming away from their Sevastopol handlers, apparently spurred to sea by a frenzy of lust. That account is already looking shady.

But fits of romance are not what stand in the way of your fleet of killer dolphins. It's easy enough to train dolphins and sea lions to hunt for mine-like objects on the sea floor or mark unidentified swimmers for security personnel to investigate. The Navy does it through typical repetitive positive reinforcement, like rewarding the marine friends with food for successful performance. What the Navy doesn't do is train them to distinguish people or objects in the water.

"You can't leave it up to a marine mammal to decide who's a friend and who's a foe. You can't train them for that," Budzyna, a spokesman for the Navy program, tells Danger Room. "How would they know which is which down there? You can't leave it up to them to make those judgment calls."

And yet there are persistent rumors that dolphins – American and Soviet – have been equipped for battle. In the '70s, a Navy employee alleged that some of the U.S.' dolphins carried hypodermic syringes containing pressurized carbon dioxide that could potentially cause a diver to "literally blow up," as our David Hambling reported in 2007. More baroque stories involve the Russians dual-purposing their own harbor-security dolphin fleet with an weapon similar to the Farallon Shark Dart.

Budzyna insists the Navy doesn't take any such gamble with its sea lions and dolphins. In addition to the lack of "operational sense" in arming a creature that can't figure out the right person to attack, he says, the danger to the animals' safety would be far too great.

What the Navy's dolphins and sea lions do without weaponry is sophisticated enough. Every day at San Diego, Navy sea-mammal handlers teach the dolphins to alert their human partners if there's a suspicious object at the bottom of the sea floor. If their echolocation picks up an undersea signature that could be a mine, the dolphin taps a disc-like pad on the side of its handlers' boat. The handler passes the dolphin a device to mark the suspicious object's location – either a beacon or something that emits a sound or releases a balloon – and then Navy explosive-ordnance disposal divers descend to take care of it.

Similarly, the Navy harnesses sea lions' ability to see in low levels of light to check out suspicious divers who might want to damage a pier. If the sea lion sees a nighttime diver, it would swim to the location and drop off another such marker for the authorities to investigate. "They work with Navy divers so that no one gets hurt," Budzyna says, either man or beast. Training such creatures typically takes two to four years.

But what the mammals don't do, perhaps the robots will, someday. The Navy's working on an undersea robot that basically fools a mine into detonating before a Navy ship is in range. There's no plans to arm it; and the Navy will have its hands full designing a robot that can outperform a dolphin's natural echolocation. But the Navy is more likely to weaponize a fleet of robotic dolphins than it is to form up a lethal armada of the real thing.