A koala hugs a tree while her baby clings to her back at the Lone Pine Koala Sanctuary near Brisbane, Queensland, Australia. Koalas have adapted to only eat the leaves of eucalyptus trees. Eucalyptus are very low in protein and toxic to many animal species. Being able to digest eucalyptus leaves is an adaptation that benefits the koala by providing it a food source for which there is little competition.

Photograph by Anne Keiser

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  • Koalas are marsupials native to coastal regions of Australia. Marsupials are mammals, just like dogs, cats, and human beings. These mammals are called placental mammals. Unlike placental mammals, marsupials give birth to tiny, underdeveloped young. Female marsupials have a pouch on their bellies, which they can zip and unzip by using a special muscle. Baby marsupials stay protected in their mother's pouch instead of inside her body. Other marsupials include kangaroos, wallabies, wombats, and opossums.

    Like all marsupial babies, baby koalas are called joeys. A koala joey is the size of a jellybean! It has no hair, no ears, and is blind. Joeys crawl into their mother's pouch immediately after birth, and stay there for about six months. That's about how long it takes for them to see, grow ears and hair, and walk (or waddle) on their own.

    When they're about six months old, joeys venture out into the world, although they stay pretty close to their mother—usually by riding on her back, like this one.

    1. Where can you find koalas in the wild?

      Coastal regions of northern and western Australia are the only places where koalas are found in the wild.

    2. Koalas are marsupials. What other animals are marsupials?

      Kangaroos, wallabys, wombats, and opossums are all marsupials. Extinct species include the Tasmanian tiger, a big cat native to Australia, Tasmania, and New Guinea.

    3. What are baby koalas called?

      Like all marsupials, baby koalas are called joeys. Joeys are born after only 4-5 weeks of gestation in their mothers' bodies.

    4. How long do baby koalas stay with their mothers?

      Koala joeys stay with their mothers about a year—six months inside her pouch, and six months outside.

  • Term Part of Speech Definition Encyclopedic Entry
    blind Adjective

    unable to see.

    coast Noun

    edge of land along the sea or other large body of water.

    Encyclopedic Entry: coast
    immediately Adverb

    at once or quickly.

    koala Noun

    medium-sized animal (marsupial) that lives almost entirely in eucalyptus trees, native to Australia.

    mammal Noun

    animal with hair that gives birth to live offspring. Female mammals produce milk to feed their offspring.

    marsupial Noun

    mammal that carries its young in a pouch on the mother's body.

    muscle Noun

    tissue found in animals that expands and contracts, allowing movement.

    placental mammal Noun

    animal (mammal) characterized by the fetus developing inside the body of the mother, in an organ called the placenta.