> One problem that I have with trying to understand "time" is that we can't measure how quickly it "flows" or at least how quickly we travel through it.

Our experience of time passing is heavily influenced by the temporal granuality of our subjective experience-at the upper end, “now” lasts 2-3 seconds; at the lower end, our temporal discrimination goes down to tens of milliseconds for visual and tactile stimuli, and reaches down to microseconds for certain types of auditory stimuli. But, one supposes other species with different neurology would have these durations be shorter or longer, which would make time pass more slowly or faster for them, in subjective terms.