I believe nerves are often related to brain stem damage...
I find when an animal's nerves are twitching & muscles are behaving like its still alive,, its often due to the upper spine/close to base of brain/brain stem being touched/damaged.
Head shòot a bunny with a 22lr & watch its back legs go like the clappers...
Whereas vaporise a bunny's head down past brain stem to neck with an explosive high velocity bullet & nothing happens...
Feral cats...same same...but VERY spectacular acrobatics if you nick brain stem...
Had a Roo recently...same thing...damage close to brain stem even with bulk of brain removed = back legs think they're still hopping into next paddock...
Just my observations...
Mind you...this theory goes out the window with sheep...bloody stoopid things think they're dead when they're not...& still breathe when they're dead...never understand them...from same planet as women i rekon...
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The man who knows everything, doesnt really know everything...he's just stopped learning...