Kangaroos are especially popular with children, although many marsupials raise their young in pouches attached to their bodies, such as opossums, Tasmanian devils and even koalas.

But what are the conditions for housing inside this case?

How is it cleaned?

Does the mother control the entry and exit of the little one?

And when does the little one refrain from entering it again?

Even more surprising: How can a mother kangaroo carry two young children of different ages in one pouch, and feed them with different types of milk as well?

Standard Specifications

Imagine the kangaroo pod as a heavy-duty hoodie, worn backwards, Rick Schwartz, animal care supervisor and spokesperson for the San Diego Zoo, California, told Live Science.

Here, the hoodie of the hoodie represents the kangaroo bag, and the ties of the hoodie are the mother's muscles that she uses to open and close the bag, as it "opens a little if the mother wants it."

The inside of the bag is kangaroo skin texture, but it is bald.

It's soft and comparable to the skin inside a human wrist, says Schwartz.

The bag is very warm on the inside, like the mother's body temperature, around 40.5°C, so you can sweat if you find yourself in it.

A kangaroo pouch has 4 nipples, or milk ducts.

When a mother kangaroo gives birth to her baby boy, known as 'joey', through the vaginal canal after 32 or 33 days of pregnancy, her baby is not yet fully developed.

About the size of a jellybean and weighing less than one gram, the newborn uses its front limbs to crawl into its mother's pocket.

There he sticks an oblong nipple that swells and hits the baby's throat, Schwartz says, holding it in place for 3.5 to 4 months.

Baby kangaroos stay inside the pouch for 4.5 to 5 months before they come out for the first time (Getty Images)

Schwartz says the baby kangaroo stays inside the pouch for 4.5 to 5 months before it goes out, then begins exploring, always close to its mother, before returning to its pouch.

Over the next several months, Joy begins to explore further and further. At around 8 months old, he becomes really adventurous, and is weaned between 10 and 12 months, at which point we don't find a baby kangaroo jumping into its mother's pouch again.

Conditions for living inside the bag

Because a baby kangaroo spends months in its mother's bag before it goes out, it defecates in it, and later when it gets a little older and starts getting in and out of it, it starts exploring and tracking dirt.

This means that the mother needs to do some cleaning work.

So she puts her entire head into the bag to get rid of dirt and droppings with her tongue, whether by cleaning around her little one, or kicking the slightly older one out while she works.

And kangaroos give birth to only one young at a time.

But when kangaroos mate and the conditions are not suitable for raising the young, as there is drought for example, the animal's body stops implanting the embryo in the womb.

Then, when the time comes, Schwartz says, the fetus emerges from its hibernation, and the mother begins to conceive.

A female kangaroo can give birth to up to 4 young in a year (Getty Images)

He added that a female kangaroo can give birth to up to 4 chicks over a year or more from just one mating.

She might give birth to one baby, then her body delays implanting the next until first Joy is a few months old and spends time outside the pouch.

"Her body can produce the right kind of milk nutrients for an 8-month-old, while the other nipple can create the right nutrients for a newborn," Schwartz says.

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