There are very few herbivores so pure they won’t supplement their diet with a little occasional animal protein. Deer will also eat baby birds, mice and other small animals. This is most commonly seen among buck leading up to mating season when they need extra calcium for their antlers. They’ve also been observed licking the bones of larger animals after predators and scavengers have already been over them.
In some versions you can try to swim, but it’s not recommended. And interestingly enough some other mythological traditions also involve a boatman who carries the dead into the afterlife.
All that is necessary for the triumph of evil is that the good do nothing.