Some snakes can stay active for up to an hour after losing their body parts... even their entire bodies. A chef in China was bitten by an Indochinese spitting cobra, Naja siamensis, twenty minutes after he severed the snake’s head in preparation for a Guangdong soup specialty.
The neurotoxin delivered by these cobras paralyze the nervous system, causing asphyxiation. While its bodily functions may have ceased, if the venom glands and the venom delivering muscles and nerves are intact, a severed snake's head can still bite.
“This kind of thing seems weird to us because we humans, like other mammals, have a high metabolic rate and require a constant blood and oxygen supply to the brain, and if this is interrupted for just a few seconds, it's lights out,” herpetologist Wolfgang Wuster of Bangor University tells TreeHugger. “Snakes and other reptiles have a much slower metabolic rate, and their tissues, including the brain, can keep alive and functional for much longer after the blood supply is cut off.”
Sadly, Peng Fan died before anti-venom could be administered.