Dr. Xavier could have finished her shift, made it home, and buried her head in a pillow if she had to. But this is much easier.
"Hi, Bar, can I have a stimulant that won't interfere with my judgement or dexterity or anything like that?"
"...Rats are tiny. Rhinos are not tiny but significantly smaller than an elephant. I suspect that elephant-rats and elephant-rhinos are smaller than just plain elephants."
"I don't actually know how big any of these things are as isolates. An elephant-rat is yea big -" She gestures a size that's a bit bigger than a regular rat. "I say 'most of' because it wouldn't have fish bones and the roc wouldn't be able to swallow it whole, it wouldn't be much of a meal really... An elephant-rhino is huge, though."
"Hey, Bar, can we have pictures of an elephant and an elephant-rhino on approximately the same scale?"
"Okay, that's about the size of an Asian elephant. African elephants are bigger, but I don't remember which one rocs were supposed to eat, so."
"She sounds nice, anyway, I have a friend who has wings and he took me up once instead of my going under my own power. It was different."
"I like having a roc. The traditional Air Avatar animal companion is a flying bison but they're a nightmare to keep and feed in an urban environment. A trained roc can be half-wild and still take passengers."
"No, flying bison are actually crossed with manatees; they fly with airbending. There's one kind of animal that can do each kind of bending except for some reason waterbending - I guess you could count the sacred koi as 'doing waterbending' but really they don't."
"There are two koi in a pool at the North Pole who represent the moon spirit and the ocean spirit. But the actual fish don't do any bending, they just swim in a circle."
"Dragons are another thing we have legends of! And some kinds of mythological dragon can breathe fire, so that makes sense."
"Dragons do totally breathe fire. There aren't many isolate dragons left, though, which is sad."
"The flying bison went through a bottleneck too but they've recovered better. They're more domesticated than dragons ever really get so people wanted them and there were obvious incentives."
"Given some of the themes of dragon-related stories in my world this does not surprise me."
"Oh--sometimes they're villainous mauraders, sometimes they're wise old beings, but they're always--orthoganal to humanity somehow."