Take a Grand Tour Inside This Kangaroo’s Cozy Pouch

Marsupials are mammals known for carrying their young in a pouch. This pouch is called a marsupium, which is a Latin word that means, of course, “pouch.” The mother and joey shown here appear to be red kangaroos, which are the largest marsupials in the world. However, with a gestation period of just over a month, how do they get so big? The answer lies within the pouch. If you’ve ever wondered what’s inside a kangaroo’s pouch, this friendly joey posted by babyanmlpics lets us take a peek inside his cozy, little home.

Why Do Kangaroos Have a Pouch?

Red kangaroos, Macropus rufus, are found in the dry regions of inland Australia. Like most marsupials, they have a short gestation period of around 28-35 days. However, the kangaroos are not fully formed when they are born. Newborn joeys are only about an inch long and weigh around 0.03 ounces. So, most of the joey’s development occurs in the mother’s pouch. Immediately after birth, the tiny joey must climb up the mother’s stomach to make its way into the pouch. The joey will latch on to one of four teats in the mother’s pouch. The teat will expand in the joey’s throat to keep them in place until they can suckle on their own at around two months old.

Kangaroo reproduction allows the mother to have up to three offspring at different stages of development. If conditions are favorable for their offspring to survive, the female mates again a few days after a joey climbs into the pouch. However, the embryo from the second mating stays dormant until the first joey is no longer in the pouch. The first joey, referred to as the “joey at foot,” will continue to nurse by sticking their head into the pouch until they are around a year old. The mother produces two different types of milk so each joey gets the nutrition appropriate to their developmental stage.

Inside a Kangaroo’s Pouch

The inside of the mother’s pouch is hairless, which allows the tiny joey to remain in contact with her warm skin. The pouch is humid and maintains a temperature of about 105 degrees Fahrenheit, which is just slightly higher than the mother’s body temperature. The skin inside the pouch is also slightly sticky. Researchers have found that the skin of a marsupial’s pouch secretes antimicrobial compounds that reduce bacteria in the pouch during lactation.

The inside of the pouch is dark as well. The mother has powerful stomach muscles she contracts to keep the pouch closed and tight against her body. This keeps the joey safe, especially if the mother is on the move. The pouch periodically becomes slimy as the little joeys urinate and defecate inside. However, the mother cleans the pouch by consuming the joey’s waste. Some scientists believe this process allows the mother to recycle about 1/3 of the water she used to produce the milk.

How Much Does a Kangaroo’s Pouch Hold?

Fortunately, the pouch is stretchy so it can continue to hold the joeys as they grow. At around 5-6 months old, the now lightly-furred joey will start to poke its head out of the pouch. At six months, they will begin exploring outside of the pouch for short periods. By this point, the joey typically weighs around 4.5 pounds.

Red kangaroos generally leave the pouch for good around eight months, at which point they weigh around 10 pounds. So, the joey shown above is most likely between 6-8 months old. When the joey is full grown, if it is a female, it will only reach around 3.5 feet tall and a maximum of 75 pounds. However, the males can grow to nearly six feet tall and almost 200 pounds. Although this little joey is about to leave the pouch, they’ll stick close to mom until they are ready to start their own family between 1.5-2 years of age.