Also, aliens could live a lot slower (say if they evolved in a relatively cold corner of the universe where there’s less energy to burn per second) and/or longe

Also, aliens could live a lot slower (say if they evolved in a relatively cold corner of the universe where there’s less energy to burn per second) and/or longer. Looking at some ‘aliens’, I don’t think ant colonies can cover an area equal to a month’s travel. ⇒ I would guess “1 month” isn’t the limiting factor. “1/p of the life expectancy of a grownup” makes more sense to me. p then would be around 500 (500 months is about 42 years)