I can’t remember exactly how it came up. I think we were talking about the zoo, and how it had condors and naked mole rats, and I mentioned that one thing it doesn’t have is a platypus, because I asked once. My companion Mika nodded. They wouldn’t probably have a platypus, she agreed, after pausing to identify a song sparrow by ear.

“Platypuses are cool,” I said. “They have duck faces and otter feet and beaver tails, and they lay eggs.”

Mika nodded. “They’re still mammals, though. And they have a sixth sense that we don’t have. Almost no one has it, just the other monotremes, and they’re not as good at it. They use it when they’re underwater and have their eyes and ears closed and they find food with it. It’s electro-…” Pause. “…Something. Electrolocation? No, that’s not it. It’s…”

I had no idea what it was. “Echolocation?”

“That’s bats,” Mika said, batting away my suggestion. “No, it has to do with…electrons? It’s in their duck bills. And they can sense the…electrons? And find food in the dark, underwater. Electro…” Pause. “…Something.”

I had no idea what it was. I was plenty happy with just the few platypus facts I had on hand. Naturally, I looked it up later. “Electroreception,” platypuses have. And electrolocation is what they do with it. It’s unknown outside of the Monotremes and it involves receptor cells arrayed in neat lines along the bill with which they can sense the electrical fields generated when a prey species, such as a small crustacean or insect larva, contracts its muscles. They move their heads side to side to home in on their dinner in much the same way owls manipulate their face fluff to direct sounds to their slightly offset ears. Or butterflies dance around to find greater and lesser concentrations of love-letters, correct course, and home in on their mates. Or asparagus beetles sniff out the only stand of asparagus in a square mile and chomp it all up before I can get to it. Where was I? Platypuses.

Mika was right on the money.

Mika is seven.

I kept reading. Platypuses are superbly designed to move in water because they’re built like little furry Volvos. They don’t have teeth, so they stash their food in their cheeks and return to the surface to mash it all up with the help of a bit of gravel, like your parakeet. Then they swallow it, gravel and all, sending it straight to their intestines because they don’t have stomachs, and then they shoot it all through a single hole like a bird. Platypus poop must be really something.

In fact, monotreme means “one hole.” Pretty strange trait to single out for an otter-footed beaver-tailed duck-headed egg-laying milk-making mammal. But for some reason people can get all worked up about anything unusual that goes on, you know, down there.

Which reminds me. Mika and her classmates are in good shape. But she doesn’t live in Florida. What are Florida children learning about platypuses? That they just barely edged out the dinosaurs on Noah’s Ark? That they are no more than simple water-weasels and Australia is a hoax? That there should be rules about whether they go to the bird bathroom or the mammal bathroom? Possibly. In Florida, toxic males are in charge.

Which brings up another thing. Platypuses can whack a foe dead with the venomous stingers on their hind feet. Just the males, of course; the females are too busy warming their eggs and tending to their petit-platties. There aren’t a lot of venomous mammals—an assortment of irritable shrews, some bats, and the famous solenodons, which you have never heard of, even though they have teats on their butt and a pencil-nose with a ball-and-socket joint at its base.

I’m sure Mika knows all that.