Pinkie Pie and Princess Skystar sat together on a rock watching the waves break against the Equestrian shoreline, dipping their tails in the water, giggling and splashing each other.
“You know,” said Pinkie Pie, “when we set off on our epic quest to save Equestria from the Storm King we didn’t know we were looking for the hippogriffs. We thought we needed the Queen of the Hippos!”
“You thought mom was a hippo!” said Skystar, raising her fore-claws to her face. “Oh that’s so funny—”
“Well not exactly. We—”
“—I just gotta tell her! How do you think she’d look as a hippo!”
Pinkie tried to be diplomatic. “Well, I've heard hippos are surprisingly graceful for their size...”
“I’m totally telling her that story. Mom told me the closest living relatives to whales and dolphins—apart from other whales and other dolphins—are hippos!”
“Hippos are related to whales. Really?” Pinkie Pie was sceptical.
“Totally. She’s spent ages studying phylogenetics.”
“Phylogenetics?”
“It’s all about the family history of different animals. How we’re all related to each other if you go back far enough. You know mom always acts all haughty and regal and pretends that as the queen she is only interested in beauty treatments and etiquette. But—” Skystar changed her voice to a conspiratorial whisper and put her beak to Pinkie’s ear to gleefully communicate the secret, “—she’s actually a secret biology nerd! She’s got loads of thick books full of family trees of all sorts of creatures.”
“She has?”
“She started off trying to trace our ancestors. It’s the sort of thing queens do. You know, to show off how far back you can trace your roots and try to get one-up on the griffons. She tracked our avian ancestors back to some pretty cool dinosaurs. She then started on the hoofed side our family—”
Pinkie Pie was intrigued. “How is it you're related to both eagles and ponies?”
“Oh—aristocratic marriages are complicated,” said Princess Skystar. “I forgot the details. It was some sort of arranged wedding centuries ago to consolidate two powerful dynasties and keep both families happy. Using magic to fudge the, y'know, genetic incompatibility issue… Anyway mom started backing up the perissodactyla family tree, then tried to trace our distant cousins. First ponies and zebras, then deer and giraffes and so on—and then she found we are distantly related to hippos and whales and dolphins.”
“You’re related to whales?”
“And you too. Distantly. Once upon a time, whales had hooves. Or at least fifty million years ago or so their ancestor was a small creature. They were a bit like cats with hooves. They lived on the land but would hide in the water when threatened. Their descendants decided it was more fun to stay in the water and they learned to swim and catch fish. And after thousands of generations their legs got smaller and their tails grew big and strong and they spent all their time messing about in the ocean and never went back to the land. Isn’t that a great story?”
“Wow,” cried Pinkie. “So the dolphins and whales used to live on land?”
“Yes,” said Skystar. “Except they weren’t dolphins or whales then. They were a sort of small whale with legs. It’s a pretty cool family history to have. I mean the fish have just stayed in the ocean since, like, foreveeerrr. I think that’s why they’re boring and never have anything interesting to talk about. Ponies' ancestors took the pioneering leap to come onto the land. Then the whale family were more adventurous and came onto land, but then went back to the sea. And that’s what gave mom the idea to turn the hippogriffs into seaponies so we could hide deep underwater where the Storm King could never find us.”
“That is a great tale,” said Pinkie. “Now let me tell you about what me and my sister Maud dug up on our family rock farm…”
Skystar grinned. “Sure. Then I want to tell you about Shelly and Sheldon’s family history. You know those guys’ ancestors go way back hundreds of millions of years.”