Classes from TypeScript NPM Package are all bundled in the build result

I created a npm package with multiple TypeScript classes which I want to use on various projects. e.g:

// dog.ts
import Animal from "../animal";

export class Dog extends Animal {
    public bark(): void { console.log('bark'); } 

This is how those classes are exported on the npm package:

// main.ts
export {Dog} from "./animals/dog";
export {Cat} from "./animals/cat";
export {Ape} from "./animals/ape";

I started a blank angular project via ng new my-app, added the npm package to my project via npm i @farm/animals and imported the Dog class to the AppComponent:

// app.component.ts
import { Component } from '@angular/core';
import { Dog } from '@farm/animals';

  selector: 'app-root',
  templateUrl: './app.component.html',
  styleUrls: ['./app.component.css']
export class AppComponent {
  title = 'app';
  lassie: Dog = new Dog();

What I realized after a production build (ng build --prod) is that the other exported classes like Cat and Ape are also bundled into the main.js build result. I assumed those would be filtered out by tree shaking mechanisms.

How can I achieve that only the imported classes are put to the build result? Is anything wrong with my export structure?

Thanks in advance!

//edit: I just realized that import {Dog} from '@farm/animals/dist/classes/dog'; does the job as expected. Is there a way to export these classes individually with a nice short name for import?