Russian forces have deployed military dolphins amid the war in Ukraine, a tactic that sounds bizarre, but has actually been used by both the US and Russia in the past.
Since February this year, the Russian Navy had two dolphin pens placed at the entrance of Sevastopol harbour, in Crimea, which was annexed by Russia. The pens have been revealed in satellite imagery from Maxar.
Sevastopol is Russia's most significant base in the Black Sea, according to The US Naval Institute's USNI News.
While the Russian warships in the harbour are out of range for Ukrainian missiles, undersea sabotage is possible.
"The dolphins may be tasked with counter-diver operations — a traditional role both the US and Russia have trained marine mammals for," USNI News reported.
"This could prevent Ukrainian special operations forces from infiltrating the harbour underwater to sabotage warships."
Submarine analyst H I Sutton told NBC News the pens seen in the satellite images from Maxar Technologies are likely the same dolphin pens Russia deployed in Syria in 2018.
In Tartus, Syria, the dolphins countered enemy divers, retrieved objects from the ocean floor and carried out intelligence operations, Sutton said.
The Naval Institute explained the Soviet Navy had several marine mammal programs underway during the Cold War and there was dolphin training in the Black Sea.
The marine mammal training unit was operational under the Ukrainian military following the fall of the Soviet Union in the early 1990s and was barely operational.
However, when Russia annexed Crimea in 2014, the unit was under the control of the Russian Navy and the program expanded and was once again an operational service.
It's believed Russia has also used other marine mammals, potentially including beluga whales.
In 2019 in Norway, a beluga whale was spotted off the coast and fishermen who reported the whale said it was wearing a strange harness, which may have had cameras attached, the Guardian reported.
The beluga whale reportedly harassed the fishermen's boats by pulling on the ropes on the side.
Russia's assault on Ukraine is now focused in the country's east and south, after Russian forces failed to capture the capital, Kyiv.
Moscow captured the city of Kherson in Ukraine's south and its forces have mostly occupied the eastern port city of Mariupol, where United Nations efforts are underway to evacuate civilians and fighters holed up in a large steel plant.
Peace talks between the two countries are at risk of collapsing, Ukraine warned.
Ukraine and Russia have not had face-to-face peace talks since March 29.
The strained relationship soured further after Ukraine accused Russian troops of carrying out war crimes near Kyiv when the forces withdrew from the area.
People were found murdered and buried in mass graves in Bucha, sending shockwaves around the world, though Moscow has denied the claims.
The two sides have had peace talks by video link.
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