That’s not quite equivalent. For one, a responsible owner is not feeding live mice to a snake. There’s at least an opportunity to ethically euthanize the mice prior to the act.

> At least the human has the mouse’s wellbeing at heart.

You don’t know this to be true

Not saying that this resolves the broader issue, but I'm not aware of any vegetarian snakes. It seems possible to differentiate this from animal experimentation.