“Fine. No thanks to any of you.” The porcupine was impressively unruffled by his confrontation with the boar. Kate supposed that getting into fights with people was probably something that happened to him on a fairly routine basis. “How’s the baby?”

“Fantastic! This is absolutely the cutest non-heron baby I have ever seen!”

“Shh!” the snake hissed. “You’ll wake him.”

Kate still found herself putting as much distance as politeness would allow between herself and the snake.

“How do you know he’s a him?” Kate said.

All the animals stared at her.

“She can’t tell,” the snake hissed.

“It must be an animal thing,” said the heron.

“Humans are animals,” Kate said a little defensively.

“Of course you are,” the fishing cat said. “But you’ve spent so much time pretending you’re not, you’ve lost the knack.”

The heron tactfully changed the subject. “Did you know that baby pangolins are called pangopups?” she said.

“That’s a stupid name,” the snake hissed.

“They should call them pangolings,” the fishing cat said. “Or pangolini!”

“Baby porcupines are called porcupettes,” the porcupine said with a shudder of disgust. “I don’t see why humans think they get to name everything. They’re not even very good at it. Electric eels—they’re not even eels. In Australia there’s a spider called a sparklemuffin!”

“And what about hellbenders?” the snake said. “Do they bend hell? Not even slightly.”

“I wish I were called a hellbender,” the cat said. “It’s such a wonderful name. Wasted on a salamander.”

“I don’t understand what just happened.” Kate still felt shaky. “Who were those animals out there?”

“Them?” the porcupine said. “Those were invaders.”

“What were they invading, the train?”

The animals all exchanged a look.

“It’s like this,” the heron said. “As an animal, you have a place where you live and a place in the order of things. You prey on somebody, somebody else preys on you. It’s not always pretty, but it keeps everything in balance.

“But sometimes an animal leaves its place in the world and goes somewhere else. Somewhere where it doesn’t fit in. Often it just dies there because the climate’s wrong or there’s nothing for it to eat—but every once in a while it lucks into a situation where it has lots of things to prey on, and there’s nobody to prey on it. What do you think happens then?”

“I don’t know,” Kate said. “It gets really fat and happy and dies of old age?”

“It eats everything in sight! Its population explodes till it’s the only thing left!”

“Oh. So those animals who tried to get on the train were trying to do that?”

“Exactly.”

“It’s just bad form,” the snake said. “I hope you quilled them.”

“I should have!” the porcupine said.

“But some of them—I mean, they were just starlings,” Kate said. “You know. Little birdies!”