What's it like inside a kangaroo pouch?

A joey is in its mother's pouch. CraigRJD received the image via a photo sharing website.

Although many animals raise their young in pouch, the most famous are the kangaroos.

What is it like inside a pouch?

Rick Schwartz, an animal care supervisor and national spokesman for the San Diego Zoo, said that the pouch of an animal is similar to a sweatshirt put on backwards. The hood of the sweatshirt is the pouch that the mother uses to open and close it. Schwartz told Live Science that it would open up if she wanted it.

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The inside of the pouch is hairless and has a texture similar to the skin of an animal. It's similar to the skin on a person's wrist. The pouch is very warm, the same as the mom's body temperature. It can get sweaty there.

There are four teats in the pouch. A joey is extremely undeveloped when it is born through the vaginal canal after 32 or 33 days of pregnancy. The newborn joey is about the size of a jellybean and weighs less than a gram. Schwartz said that the teat swells and pokes down the throat of the baby, holding it in place for about three-and-a-half to four months.

The joey stays inside the pouch for about four-and-a-half to five months before emerging, and then it begins to explore, always staying close to its mother, before returning to her pouch, Schwartz said. The joey begins exploring farther away and for longer durations at around 8 months old, and at this point it really gets adventurous. The joey weans between 10 and 12 months, at which point it no longer hops back into the pouch.

The joey defecates inside when it spends months in the pouch. Schwartz said that the joey tracks dirt in later in development because it is coming and going to explore. That means the mama needs to clean up. To clean the pouch, she sticks her head in to get rid of the mess and then kicks out an older joey or a young one.

There are only one joey at a time. If there's a shortage of water, the animal's body will hold off on implanting the embryo into the uterus. When the time is right, the embryo comes out of dormancy, and the mother starts to have babies.

He said that the female can give birth to up to four young over the course of a year or longer. She may give birth to one joey, then her body will delay the next embryo's implant until the first joey is a few months old. He said that the body can produce the right milk for an 8-month-old and that the other teat can create the proper nutrition for a newborn.

Live Science published the original article.