'Killer dolphins' escape? Not so fast.

'Killer dolphins' escape: A story of highly-trained killer dolphins escaping from a Ukrainian military facility has turned out to be a hoax. But there is such a thing as a military dolphin.

Three "killer dolphins" trained by the Ukrainian navy to kill combat swimmers, possibly armed with guns or knives attached to their heads, have escaped and are now roaming the Black Sea in search of a mate.

At least that's what a Ukrainian and Russian news outlets are claiming, and it's almost certainly not true. 

The state-owned RIA Novosti repeated stories Thursday from Ukrainian media outlets that said that, following a training exercise in the Crimean port of Sevastopol, only two of five military-trained dolphins returned to their handler. From there, the story was picked up by many English-language news outlets.

But Ukraine's Defense Ministry has denied the reports, and has refused to confirm that its navy even has a dolphin program.

The Atlantic, which originally accepted the report as more or less factual, followed up with the news that the story is a hoax, apparently started by a museum director. 

But is it plausible? Does the Ukrainian military train dolphins for warfare? 

Apparently, it does, just like the US Navy does. Beginning in 1973, the Soviet Navy in Sebastopol trained dolphins to detect military equipment such as mines on the seabed, to attack divers, and even to carry explosives on their heads to plant on enemy ships.

After the USSR broke up and the Black Sea Fleet divided into Ukrainian and Russian fleets, the Ukrainian Navy took over the dolphin training section, which then were used for civilian goals such as working with disabled children. In 2000, the BBC reported that many of the trained dolphins, along with several sea lions, walruses, and a beluga whale, were sold to the Iranian government. 

Dolphins are believed to be the world's second smartest animals, at least by human standards, with a large capacity for social cognition.  US Navy officials said dolphins have exceptional sonar and deep diving capabilities that outperform anything human divers or the latest technology developments can provide. The US Navy has relied on specially trained dolphins and sea lions to find sea mines, that, if not found, could sink ships, destroy landing crafts and kill or injure people, according to the American Forces Press Service.

US military dolphins programs date back to in the early 1960s, when the military first started to study the aqua-dynamics of the mammals to help them design ships and submarines. The Navy quickly realized the animals could be used for more complex assistance tasks.

In addition to dolphins, the US Navy has also trained whales, grey seals, and sea lions for military purposes. Such marine mammals are so important that there is an entire program dedicated to studying, training, and deploying them, called the Navy Marine Mammal Program (NMMP).

The dolphins, according to NMMP officials, usually receive two or three years of specialty training before working on underwater security projects. Recently, NMMP, which is based in San Diego, Cal., used its militarized dolphins to train Montenegrin Navy divers to locate and clear underwater mines and explosives dating back to World War I.

Last year, the Navy announced that it would be laying off some of its mine-seeking dolphins, replacing them with robots.