One of the ways to mark lab mice is to punch their ears. #1 would have a hole on the right, #2 would be one on the left, etc etc.
I’m not the biggest fan of animal experiments. I think these should be done as humanely as possible and only when absolutely necessary. I thought punching the ears would be like piercing our ears and thought that wouldn’t be too bad. However, I saw mice squirming their faces as their ears get punched (not by me) today. It occurred to me then that if 1/10 of my ears get punched, that would hurt like “a” hell (Mako likes to count hells).
If this procedure is necessary, at least put them to sleep…