Every life is precious, no doubt about it at all. Among the wide range of creations of the Absolute, human birth is the most glorious and at the same time most difficult to attain too.
According to scriptures there are three types of birth:
It is quite amazing to learn about how these births are got and the unique characteristics of each of them.
A human being in his life does a variety of deeds which has to reap fruits during his next birth tenure. The fruits thus accumulated in several past births accompany him all through. When only the praiseworthy deeds alone comes to fruition, the Jeevi (Individual Consciousness) will obtain a Divine birth in heaven and enjoys all type of pleasures and luxuries since that is a world allocated for pleasures and there are no sorrows. As long as he is in the heaven he can enjoy luxuries based on his past good deeds, but he does not and cannot do fresh deeds. There is no chance for him in heaven to perform any meritorious deeds to attain eligibility for salvation and merge with the Absolute. At the extinction of the fruits of his good deeds derived by his previous good acts, he must get back to land of mortals or human world. In this world of humans he again gets into the cycle of births and deaths. When in heaven he is gifted with mere subtle sensory organs which enable him to enjoy joys and pleasures, but he does not acquire the human body which is an essential medium for performing deeds. So the Divine birth is not of any avail in the attainment of salvation or reaching the Almighty.
In the case where the cumulative of sins committed by a Jeevi is ready for fruition he takes the birth of an animals, or insects, or birds, or worms or germs depending on the intensity of sinful acts committed by him. During this birth the Jeevi undergoes all types of humiliations and torments. Unfortunately in this birth the Jeevi is not blessed with Viveka, power of discrimination. It has Deha (Body) and Manas (Mind) without Buddhi (Intellect). The actions performed in this stage are not deliberate but impulsive stimulated by their basic instinct. Therefore in this kind of birth the Jeevi has no idea as to what has to be done to attain Salvation. It can only take pleasure in enjoying the fruits of its deeds in the previous births. Thus in the Animal birth Jeevi fails to attain any thing or do any act essential to endorse him to a higher stage and to have a merger with the Almighty.
If we consider the third aspect in which the fruits of merits and demerits begin to yield mixed results. The Jeevi takes the birth as a human being. In this phase he is experiences both pleasure and displeasure as yielded by his past deeds. In enjoying the fruit of his merits and sins in this birth he is unknowingly doing fresh deeds. Here in this form he is not only gifted with Deha (Body) and Manas (Mind) but also provided with Buddhi (Intellect). By this intellect Jeevi is blessed to do deeds with discrimination and deliberation and has profound capability that it can be used to achieve enlightenment and benefit human birth.
Therefore as a human being Jeevi has the ability and opportunity to perform meritorious deed for which he has to forego the enjoyer-ship so that it enables him to merge with Absolute and avoid the cycles of birth and death. Hence this birth is looked upon as the one that excels all other births and as the most difficult to attain.