Given 10 billion bats , that bats have been around for 50 million years, and bat generations taking let's say 5 years, and assuming that population has been stable for evolutionary history, we have a super rough estimate of something on the order of (10B * (50M/5)) = 100 quadrillion historical bats. I think a lot of anthropic calculations assume there have been 100 billion historical humans, so probability of being a human is 1/1 millionth the probability of being a bat.

I don't see a whole lot of difference between not having subjective experiences and having one one-millionth the subjective experience of a human. Once we expand this to all animals instead of just bats, the animals come out even worse.