Photo credit: Stefan Kraft
"Hello, class. Today we'll be meeting Percy here, who is a platypus. Take a look at his duck-like bill, webbed feet, and flat tail. There really is no other animal like the platypus. The first ponies to write about platypuses thought they must have been some kind of magical creature, maybe conjured up by an ancient unicorn wizard!
"Now we know that platypuses may not be magical, but they certainly are marvelous creatures. Even though they have a bill like a duck's, platypuses are mammals, and like most mammals they have fur. They have a lovely, dense coat that insulates them underwater. Yes, Ocellus?
"Oh, that is a good question. Most animal experts I know say 'platypuses' for more than one platypus, but Twilight tells me that 'platypodes' would also be correct. I'll stick with 'platypuses', if you don't mind.
"Now if I place Percy in this water tank right over here, you'll be able to see how he swims. He paddles around with his front paws and uses his back paws and tail to steer.
"The platypus' bill is a most wonderful tool. Platypuses keep their eyes, ears, and nostrils closed when they're underwater, you see, so they use their bill to feel their way around. They also use their bill to detect electricity! The muscles of all animals, including all of us, fire off tiny electric charges when we move. Because they are able to sense this, platypuses can hunt for prey even when they cannot see, hear, or smell a thing.
"Platypuses like to eat worms, insects, and crayfish, but Percy agreed that he would only eat these protein pellets while he's in the classroom. He needs a lot of food to keep his little body warm, so when he's awake he spends nearly all his time looking for food. Platypuses lose all of their teeth before they're fully grown, instead they grind their food using hard plates in their bill.
"Yes, Gallus, it is true that male platypuses are toxic, but experts prefer to use the word 'poisonous' only for animals that can poison others if they try to eat them. Male platypuses inject toxins using a spike on the back of their ankle, and an animal that injects their toxins into other creatures is said to be 'venomous'.
"So far, nopony has ever died from platypus venom. However, ponies who have been poisoned by a platypus have said that it was so extremely painful that, um, they wished they had. The pain can last for days, or even months.
"But it's very rare for platypuses to use their venom on ponies. Percy certainly won't unless you give him a good reason to. Platypuses only use their venom on ponies if they've been scared, like if somepony is trying to catch one. More often, they use their venom on one another. Male platypuses fight each other with their ankle spikes over territory and mating rights. In fact, they stop producing venom when breeding season is over.
"A female platypus raises her young by herself. She digs a deep burrow on the side of a riverbank, then brings in dead leaves with her tail to make a soft, comfortable nest.
"The platypus is one of very few mammals that lay eggs, and the female platypus lays between one to three adorable eggs at a time. When the babies hatch, they are blind and hairless, and their mother feeds them with milk that oozes from the skin of her belly. After four months, the babies are ready to leave the burrow.
"Well, it looks like Percy has found and eaten all the protein pellets I gave him, so that will be all for today. Have a lovely day, everycreature, and stay kind to each other."
I seem to recall hearing that even morphine won't help the pain of platypus venom, because it takes a different chemical path to causing it than most sources of pain or something.
If so, I would strongly suspect that it is a useful resource to people researching new pain-killers, and maybe other aspects of pain.
This fanfic is very cute, and you nailed Fluttershy's voice.
I can't stop thinking that she's referring to Perry the Platypus
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Fun fact! Do you know why salt on a wound is so painful? Sodium ions are the trigger for pain-sensing noiceptors in the peripheral nervous system. These ions are released by the body in normal situations, but just imagine dumping a bunch in externally.
Morphine blocks off a lot of those receptors (including some of them that aren't related to pain, which is why it is so dangerous of a drug), but if I remember correctly, it doesn't block off all of them. Maybe platypus venom affects those.
When I was a little kid, which is longer ago than I care to think about, a local tv station had a Saturday morning live kids show called The Percy Platypus Show. It was pretty good for a local production.