> 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.

https://www.cia.gov/readingroom/docs/CIA-RDP96-00792R0006003... (page 12)