The kangaroo, symbol of Australia, is a marsupial with which the females are endowed with the famous ventral pouch that makes their reproductive system so peculiar and striking.
The kangaroo is a very surprising animal that has known how to adapt perfectly to an arid and unwelcoming environment, its success in this environment is explained by an extraordinary biology at the service of its ability to reproduce.
In this article on our site we are going to tell you about the reproduction of the kangaroo so that this extraordinary phenomenon has no more secrets for you.
A playback in rhythm with the environment
Kangaroos have managed to multiply and evolve in an environment as arid as Australia thanks to some biological adaptationsspecific reproductive.
When food is scarce, kangaroos stop reproducing: they become sterile, which ensures a balance between the size of the group and the resources available in the environment. But once the drought is over, you have to compensate: the female can get pregnant again. Find out more about feeding kangaroos.
When the grass becomes green and abundant again, after the rains, the kangaroos reproduce again and to compensate for the mortality due to the drought that has just passed, they have a specific strategy: thechain play.
Chain Play and Red Kangaroo Diapause
A day or two after the birth of her first baby, the female mates again and the created embryo goes into dormancy or “dormancy” in the womb This phenomenon is called: “ embryonic diapause”: the development of the fetus stops. The diapausing embryo will be activated only once the first pup has come out of the sac, and then a month later the second pup will be born, and the female will be able to mate again.
This means that the female red kangaroo has always 3 little ones on the way: one outside the bag, one inside the bag and a sleeping embryo in her womb.
A very short gestation
Kangaroo reproduction stands out in the animal kingdom: after a very short gestation that lasts for 30 to 38 days, the little one is born at an early stage, measuring about 2 cm and weighing 0.8 grams. And it goes in the ventral pouch to suck during the months that remain to finish its development.
Only the female can give milk to the little ones: the marsupium or marsupial bag contains the nipples.
Uterus to pouch
Since her birth, the baby kangaroo, which is no bigger than a peanut and hairless, traces a path all by itself to its mother's belly pouch. The ascent of the baby kangaroo from the uterus to the pouch takes almost 5 minutes: it's an effort enormous for such a small and fragile being. Then it goes into the bag where it can feed on milk and stays there warm and protected from the dangers outside.
It will stay about 5 months in this kind of “incubator” that is the marsupium and when it feels ready, the little kangaroo ventures out of the bag, like a second birth, but stays close to his mother until weaning.
A busy bag
After about 5 months in the bag the first baby begins the first exits out of the bag and his mother definitely encourages him to independence around 6 and a half months of life, but the little one will continue to suckle by burying his head inside the bag for about 4 more months.
At 6 and a half months after the first baby, that is, when he no longer returns inside the bag, the second is born, just about 24 hours after the first one left the bag free.
Each one his nipple
The first continues to suckle occasionally, while the second stays inside the bag all the time.
Each one has a nipple: the two nipples produce milk of different composition adapted to the stage of development of each of the little ones. The nipple of the first young man who was used for months is more swollen and longer and is now too big to be used by the small one that the other uses by default.
What about kangaroos that don't have the diapause mechanism?
- The kangaroo Eastern gray, lives in more clement conditionsand only rarely triggers the diapause phenomenon.
- The Western gray kangaroo does not have the biological capacity of diapause, its seasonal reproduction is highly adapted to the rhythm of the rains which limits the risk of death, but it is unable to quickly re-create a population in the event of a long drought.
And the males in all this?
A male fertilizes about 20 females and many males want to be the parent: they fight before mating to decide who will fertilize the female. The males fight, standing on your hind legs and their tail like a tripod and hitting each other with their forelegs like boxers
A kangaroo mother gives birth to females when she is young, while when she is older she gives birth to males
Discover more about kangaroos in your pregnancy in our article: What is the kangaroo bag for.
