Question

I've seen a number of animals - dogs, cats, squirrels, ducks andgeese, etc drink from puddles, some of them were muddy, others hadgreen flora growing under water. Same goes for lakes and rivers. Ahuman would not drink that. Do animals experience gastrointestinaldiscomfort or can they die from drinking water like that?

At the same time I hear about the problem of "clean water" in3rd world countries and how diarrhea is the #1 killer of childrenunder 5.

Are humans the only animals that require a certainpurity of their drinking water? Why is it that a dog candrink from a puddle, but a human is likely to get sick from doingthe same? Do baby animals get sick from drinking "dirty" water?