There are differences that occur beyond the similarities of a "bleed". Other species have an estrous cycle.
Oh, and now I'm confused, and emailed my prof for clarification. In "human" classes I've taken, menstruation was stated as being unique to humans, that other species have an estrous cycle. But now that I'm looking further (to find a link or two to explain it better and post it here...), I see some references stating that menstruation is also found in the great apes...then another broadens that to include old world monkeys...Now I'm wondering if the "human" classes are more specific about how they define "menstrual cycle" versus "estrous cycle", and the "mammal" classes are a bit fuzzier with the distinctions, and lump things together. I'll let you know tomorrow -- I have my PsyBio of Repro class in the morning.
