Koalas are special animals called marsupials. This is because of how they have babies and how their bodies are made.
First, let's talk about their babies. When a baby koala is born, it is really tiny—like a jellybean! The baby koala can’t survive on its own yet, so it has to climb into its mommy's pouch. Just like a pocket, a pouch is a safe and warm place where the baby can grow and drink milk until it gets bigger.
Second, marsupials are different from other animals because of their pouches. There are other marsupials too, like kangaroos and wombats. They all have that special pouch that helps keep their babies safe.
So, in short, koalas are marsupials because they have a pouch to carry and care for their babies. Isn't that neat?