> People back at shore would dip the bandages from a wound inflicted on a dog, which would supposedly cause the dog on board to yelp.
That kind of morbid experimentation was apparently still in fashion during the Cold War:
> Dr. Pavel Naumov … conducted animal biocommunication studies between a submerged Soviet Navy submarine and a shore research station; these tests involved a mother rabbit and her newborn litter and occurred around 1956 … . When the submarine was submerged, assistants killed the rabbits one by one. At each precise moment of death, the mother rabbit's brain produced detectable and recordable reactions.
That kind of morbid experimentation was apparently still in fashion during the Cold War:
> Dr. Pavel Naumov … conducted animal biocommunication studies between a submerged Soviet Navy submarine and a shore research station; these tests involved a mother rabbit and her newborn litter and occurred around 1956 … . When the submarine was submerged, assistants killed the rabbits one by one. At each precise moment of death, the mother rabbit's brain produced detectable and recordable reactions.
https://www.cia.gov/readingroom/docs/CIA-RDP96-00792R0006003... (page 12)