You don't know that as fact. I have heard of people using small tupperware or other lidded containers with a small whole cut into the middle of the lid to help prevent it from spilling. Then when the snake crawls in, the water level rises because of the snake's added body volume up to the very top of the lid, and they desperately search along the side to escape, not being "smart" enough to go back out the CENTER hole they came in from......so they drown.
No, not real common, but a definite reality that has happened before once in a great while.
I'm not saying it couldn't have died from something else either, I'm just saying it "can" and has happened before and is a possiblity. Without a necropsy, nobody will know exactly what went on there.
~Doug
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"a snake in the grass is a GOOD thing" 

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