A couple of things don't add up for me.
Aren't mussels usually found in larger bodies of water than small ponds?
On page 1 they say they found the snake in the grass and leaves. On page 2 they say the snake must have drown. If it drown, wouldn't it be under water?
Anyway -
I saw something on the Discovery Channel that showed a certain type of mussel that were preyed upon by a certain type of snail. The snail would slowly crawl across the bed of mussels, pick one, slowly scrape a hole in one of the mussel's shell, and eat the mussel. Well the mussels use strong threads (kind of like strong spider web) to adhere to the rocks. The surrounding mussels would anchor the snail to the rocks with their threads so it couldn't move. I thought that was pretty amazing. But they went so far as to say that once the snail started scraping at a mussel's shell, the most common cause of mussel death was heart attack. Kind of made me see them in a whole new light.