Marine mammals in military

About Beluga whales
Beluga whales generally live in the icy waters around Greenland, Norway and Russia. They can grow up to 6 m long, and are related to dolphins.

About their military use
Over the last few weeks, a beluga whale swimming in the Arctic off Norway has given rise to speculation that it is a spy being used by the Russians. It is tame, allowing humans to pet it, and one video shows it returning a phone to a woman who had accidentally dropped into the ocean.

Marine mammals in military
Other marine mammals are known to have been used for military use, including bottlenose dolphins by the US Navy since the 1960s. A dolphin can identify objects underwater that would be invisible to human divers. They have even helped clear mines in the Persian Gulf War and the Iraq War.

So, is this one a spy?
While Russia has not issued any official reaction, but Russia does has programme to train whales.

 (Source:https://indianexpress.com/article/explained/can-a-beluga-whale-be-trained-as-a-military-spy-5726046/)