The reproductive system of kangaroos is quite different from that of other mammals. The kangaroo embryo goes through some stages outside the womb, which normally occur in the womb.
Soon after fertilization, the blind kangaroo offspring, which is approximately a centimeter, comes into the world. Usually, only one is born at a time. At this stage, it is called "neonate." While all mammals go through this stage in the mother's womb, the kangaroo offspring comes into the world when it is only one centimeter long. It has still not developed: its fore feet are indefinite and its hind feet are comprised of small projections.
No doubt, the offspring cannot leave its mother in such a state. Coming out of the womb, the neonate starts to move up in its mother's fur with its fore legs and reaches to its mother's pouch after a three-minute journey. To the little kangaroo, the pouch means the same as the womb means to other mammals. Yet, there is an important difference. While others come into the world as babies, the kangaroo is merely an embryo when it comes out of the womb. Its feet, face and many other organs have not yet taken their final shapes.
The offspring reaching the mother's pouch attaches itself to one of the four nipples there, and starts to suckle.
At this stage, the mother goes through another ovulation period and a new egg forms in its womb. The female copulates once more and the new egg is fertilized.
This time the egg does not start to develop immediately. If drought rages in Middle Australia, as is often the case, the fertilized egg in the womb remains undeveloped until the drought is over. If, however, heavy rains fall and if there are rich pastures available, then the development of the egg restarts.At this stage, we are faced with the question: who makes this calculation; who arranges the development of the egg according to the conditions outside? The egg cannot by any means make this arrangement itself; it is not a complete living being, it has no consciousness, and it is totally unaware of the weather conditions outside. The mother cannot make this arrangement, because, like all other living things, it has no control over the developments taking place in its body. This extraordinary event is definitely controlled by God, Who has created both the egg and the mother.
When weather conditions are convenient, thirty-three days after fertilization, the new neonate, only as big as a bean, creeps up from the mouth of the womb and reaches the pouch just like its sibling did.
In the meantime, the first neonate in the pouch has grown considerably. It leads its life without doing any harm to its sibling, which is only one centimeter long. When it is 190 days old, it has grown mature enough to make its first journey outside the pouch. From then on, it starts to spend most of its time outside the pouch and leaves the pouch for good on the 235th day after its birth.
Soon after the birth of its second offspring, the female copulates again. Consequently, the female has three offspring all dependent on her. The first can feed on grass but occasionally comes back to its mother to suckle; the second younger offspring is still developing by suckling; the third is the neonate, which is the youngest.
What is more astonishing than that all three offspring, each in a different stage of development, are dependent on the mother, is that all three offspring are fed by different types of milk according to their sizes.
While the milk the offspring suckles as soon as it reaches the nipple in the pouch is transparent and colorless, it increasingly turns whiter and starts to look like real milk. The amount of fat and other ingredients in the milk increases in parallel with the development of the baby.
As this young one keeps on suckling the milk prepared for its own needs, a more easily digestible milk issues from the nipple that the second baby reaches. Thus, the body of the mother simultaneously produces two types of milk with different ingredients. When the third is born, the number of milk types produced with different ingredients becomes three: highly nutritious milk for the older, and relatively less fatty and nutritious types of milk for the younger. Another point to note here is that each offspring finds the nipple specially prepared for itself. Otherwise, it would suckle milk with an ingredient likely to be harmful to its body, and the milk it suckles would harm it.
This feeding system is very remarkable and it is obviously a special product of creation. The mother cannot, by any means, arrange all these consciously. How can an animal specify the ingredients of milk needed by its young of different sizes? Even if it did, how could it produce it in its own body? How could it distribute these through three different channels?
Doubtless, the kangaroo is not capable of doing any of these. It is not even aware that the milk delivered by its body is of three different types. This wonderful process is unquestionably an outcome of the created nature of this animal.
Do they not reflect in their own minds? Not but for just ends and for a term appointed, did Allah create the heavens and the earth, and all between them: yet are there truly many among men who deny the meeting with their Lord (at the Resurrection)! (Surat Ar-Rum, 8)