Rays of sunlight beamed warmly through the tall-windowed, beige-walled lecture hall, centering on a lab-coated figure like a spotlight. Science majors and liberal arts students stood or squatted, gawking over or around each other, angling for a better view of the fuzzy duck-billed critter she was holding.
"Today we're learning about mammals," said Dr. Kristof, the bio prof. "My little friend here came here from our university zoo across campus. His name is Tuzzy. Some of you might recognize him as a platypus."
A front-row student stuck up a hand. No one called on him but he spoke anyway: "Is it true some scientists thought they weren't even real, like a fable or hoax?"
"Yes," answered Dr. Kristof, "Tuzzy here is a freaky little fella. Cute, but weird. Weird for a mammal anyway. Those of us in the field think the placentals diverged from marsupials and especially monotremes a very long time ago."
In a thick southern drawl, one of her students asked "Marsupials is like roos and possums, ain't that right?" Students who didn't have class with her thought she was stupid because of her accent, but she always got A's in bio.
"Yeah, but what on earth is a placental?" asked her boyfriend sitting next to her, pretending he had also known what a marsupial was. He took a lot of science to be with her but he was less intelligent. After a second with his hand on his chin, he also asked, "Heck, what's a monotreme?"
Dr. Kristof smiled. "Well, the overwhelming majority of mammals are monotremes, from the Greek meaning ONE HOLE. Dogs, cats, horses, deer, elephants, even humans. Similar to birds, we urinate and defecate through a single opening called a cloaca. The male's erect penis emerges through his cloaca, and the female lays her eggs from her cloaca. Of course, our mammal eggs are leathery rather than hard-shelled, but the idea is the sa--"
One of the rude footballers in the back interrupted. "Ugh, we all saw the puberty video in middle school health class, what's your point?" His buddy punched him hard in the shoulder. Most of the jocks really wanted to here about women's cloacas!
"My point is, this little guy is different. Tuzzy and his distant cousins, the echidnas, are placental mammals. The females have separate holes for solid waste, liquid waste, and reproduction. Tuzzy's a male, but he still poops through a separate hole. See these little dangly bits between his hind legs though?"
"Are those his venom glands?" asked the southern girl from earlier. Her classmates looked at her as though she'd gone mad. A venomous mammal? How ridiculous! But Dr. Kristof didn't think it was ridiculous.
"No, those are in his thighs, and the injection spurs are on his ankles, which is why I have to hold him by the tail like this," the lecturer corrected. "Hanging between Tuzzy's legs are his testes, which are always outside his body in a scrotum. And this is the urogenital tubule--his penis, except it's always external, and he also pees through it. Sperm and urine through the same hole in the tip."
At that little revelation, the whole lecture hall erupted: "Peeing through a penis?" "Wait, males and females don't have the same number of holes?!" "What did she say a scrotum was again?" "Their "Hahaha, platypus DICKS are always out!" "Seriously? VENOM?!"
"Like I said, placental mammals are weird, the platypus especially," said Dr. Kristoff. "They're named after something called a placenta that connects their young to the mother's insides until they are born. No egg forms. Instead, they give live birth like certain reptiles."
"Now you're just messing with us," said one of the usually quiet students in the back. The idea of mammals giving live birth was just too much for him.
"That's what the English scientists thought when this creature was discovered," said Dr. Kristoff. "But they're very real. Very different, but very real." She put Tuzzy back down into his cage and continued, "That's why our first research project of the semester will be on how scientists define mammals. How is it that we are more related to Tuzzy than we are to birds who excrete and reproduce more like we do? Let's go over the instructions..."
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In this universe, Dr. Kristof's students are learning about the bizarre and nearly unbelievable strangeness of placental mammals. Mammals who DO have external penis/testes and DON'T lay eggs through a cloaca.
But elsewhere, someone is getting ready for bed. Someone in another universe. Perhaps in a universe much like your own. A universe where evolution took a different path, where placentals are extremely common, and only fantastical, strange mammals such as the platypus are monotremes. A universe where men have been fucking vaginas forever, where their penises DO carry urine and DON'T vanish into their assholes when flaccid. A universe where women make love and make babies through an opening they don't also shit out of.
Who is going to bed in their placental-mammal universe tonight? How will they react if they were to wake up in Dr. Kristof's universe, with only a single hole between their legs? Perhaps we're about to find out.