What’s Inside A Kangaroo’s Pouch?

A kangaroo pouch may look like a simple pocket, but it’s actually a complex nursery specially designed to care for a growing joey.

After all, the newborn baby is just the size of a jellybean when it crawls into the pouch and grows to the size of a large house cat. So, the pouch is equipped with goodies like nipples that release customized milk and germ-fighting sweat glands.

At first glance, a kangaroo's pouch looks like nothing but a built-in baby sling. But if you peeked inside, you'd see it's far more complex than a simple pocket.

It has to be, because the joey inside is not your average baby. An adult male red kangaroo can stand over

1 1/2 meters tall and weigh 90 kilograms. That's larger than a grown man. But the newborns start out the size of jelly beans.

They're blind, deaf, and hairless to boot.

After all, they only spend 33 days inside their mom before birth.

That's like a human having a baby when she's two months pregnant. So the underdeveloped roo isn't ready to face the harsh Australian wilderness.

That's where the pouch comes in.

It's a pocket of skin that acts like a second womb, giving the joey a safe, cozy environment to grow.

And, like a pregnant belly, the pouch can stretch to fit the baby as it gets bigger.

It's lined with powerful, but flexible, muscles and ligaments.

To keep the joey safe, mom can tighten those muscles to shut the pouch flush against her body, just like pulling a drawstring bag closed. And it will need the extra space, because over the course of eight months, that bean-sized baby will reach the size of a large house cat. That's thousands of times its birth weight.

That rapid growth is thanks to the pouch's four nipples, which spout milk that contains germ-fighting antibodies to keep the little room from getting sick.

But that's just the start. You see, the nutrient levels change to meet the baby's needs as it ages.

For example, sulfur, a major building block of hair, peaks around three months in. That's the same time the baby starts growing fur.

The best part?

Mom can produce multiple types of milk at the same time, each squirting from its own nipple. So she can suckle two babies in different age groups simultaneously.

Another special feature about the kangaroo pouch is that it's lined with sweat glands that release antimicrobial substances,

which help protect the baby roos from harmful viruses, bacteria, and parasites. But there's one more way that pouch's design keeps the joey safe.

It's totally hairless, and that skin-to-skin contact keeps the baby warm and cozy.

Basically, it's the ultimate nursery. But nothing lasts forever.

Eventually, the joey will need to leave the pouch. At about 5 months old, it pokes its head out.

And a month later, it takes its first tentative steps into the world.

There, it will explore for a few short seconds before high-tailing it home.

But as it gets older and bolder, it stays out longer, until eight months in:

It's ready to leave the nest, well, the pouch, for good.

kangaroo fun facts

Here are some interesting facts about kangaroos:

1. Kangaroos are marsupials native to Australia, and they are known for their strong hind legs and powerful tail, which they use to hop around and balance while they move.
2. The largest species of kangaroo is the red kangaroo, which can reach up to 6 feet (1.8 meters) tall and weigh up to 200 lbs (90 kg).
3. Kangaroos can reach speeds of up to 40 mph (65 km/h) when they are hopping, and they can jump up to 10 feet (3 meters) in a single bound.
4. Kangaroos are herbivores, and their diet consists mainly of grass.
5. Kangaroos are social animals, and they live in groups called mobs or troops. The dominant male in the group is called the boomer, and he is responsible for protecting the group and mating with the females.
6. Kangaroo babies, called joeys, are born after a gestation period of just 30 days. When they are born, they are tiny and blind, and they crawl into their mother's pouch where they continue to develop.
7. Kangaroos have a unique reproductive system. Female kangaroos can have multiple partners and can delay the development of their embryo until conditions are right for the joey to survive. This means that a female kangaroo can have a new joey developing while an older joey is still in her pouch.
8. Kangaroos are an important cultural symbol in Australia, and they appear on the country's coat of arms. They are also popular as a subject in art and literature, and they are often depicted in Australian tourism advertisements.