"TIL That rats can be trained to detect a chemical compound within explosives, meaning they ignore scrap metal and can search for mines more quickly. Also, an African giant pouched rat named Magawa has been awarded a prestigious gold medal for his work detecting land mines."
I'm sure it was observed that there was a wide range in the amount of time living rats would be found in water after something that would have caused them to fall in.
To establish what mechanism was causing the disparity it would be extremely easy to test a rats reactions to different scenarios without actually killing the rat, not to say they didn't anyway though.
The point is that information relating to potentially extending survival time in a disastrous situation is among the most valuable things to study. Can you not recognize why that would be important to understand?