A Russian naval base is defended by dolphins. It's not as unusual as it sounds

https://www.npr.org/2022/04/29/ [login to see] /russia-dolphins-black-sea-naval-base
Russia's military is using specially trained dolphins to defend a critical naval base off of Crimea, according to an analysis published by US Naval Institute News.

Submarine analyst H I Sutton wrote in the publication — which is editorially independent from the nonprofit USNI — earlier this week that satellite imagery from Maxar Technologies shows two dolphin pens at the entrance to Sevastopol Harbor, the Russian Navy's "most significant" naval base in the Black Sea. He said the pens were moved there in February, around the time that Russia launched its full-scale invasion of Ukraine.