Russia appears to have deployed trained military dolphins following its invasion of Ukraine. Satellite imagery analyzed by The US Naval Institute (USNI) suggests that Russia has set the military dolphins the task of protecting its Black Sea naval base.

According to USNI, two dolphin pens were moved in February at the start of the invasion and placed at the entrance to Sevastopol harbor. The USNI believes that the dolphins may be there to counter diver operations at the base, which is crucial given its location at the southern tip of the Russian-seized Crimean Peninsula.

Ships stationed at the base are out of range of Ukrainian missiles, but could be vulnerable to underwater sabotage attempts, hence the need for trained dolphins. 

Both the US and the Soviet Union started programs training military dolphins (and sea lions for the US, belugas for the USSR) during the Cold War.

Following the fall of the USSR, the dolphins were taken on by the Ukrainian military, before being taken back by Russia when it annexed Crimea in 2014. Ukraine tried to get the dolphins back but Russia held onto them and has since tried to expand the program.

"Our specialists developed new devices that convert dolphins’ underwater sonar detection of targets into a signal to the operator’s monitor. The Ukrainian navy lacked funds for such know-how, and some projects had to be mothballed," one Russian source said, as seen by The Guardian.

According to Ukraine, however, many of the dolphins appeared to refuse to defect to Russia, went on hunger strike, and died "patriotically".

As well as dolphins, Russia is known to use beluga whales in the Arctic, given their suitability to colder environments. One beluga, named Hvaldimir, believed to have been released from captivity by Russia became famous in 2019 when it was seen "playing fetch" with a rugby ball.

The beluga approached a fishing boat wearing a harness stamped with "Equipment of St Petersburg", prompting speculation that it may have been a Russian spy whale, with a harness used to mount a camera. 

“We know that in Russia they have had domestic whales in captivity and also that some of these have apparently been released. Then they often seek out boats,” Professor Audun Rikardsen of the Arctic University of Norway told NRK at the time.

"If this whale comes from Russia and there is great reason to believe it does, then it is not Russian scientists, but rather the navy that has done this," Martin Biuw of the Institute for Marine Research added.

Sadly, Hvaldimir did not fare well after its release by the Russian military, and lost a lot of weight as it attempted to live away from human care. The whale, now under the care of the Directorate of Fisheries of Norway, has since seen significant improvements in its physical condition. Its tendency to seek out boats, however, has seen it receive several injuries from propellers.