There are 4 types of bodies a soul can have: human (Manushya), animal (Tiryanch), heavenly being (Dev) or hellish being (Narak). Each soul is rewarded with a particular body according to their behaviour in previous lives. Therefore souls which have been good are born in heaven or human form, and like wise souls which have been sinful are born as an animal or in hell. When a soul becomes bhagwan he is completely detached from emotions and material things. He does not have any of these types of bodies and is free from the cycle of life and death.
Human Beings: As the human beings we have been endowed with the ability to think. We can comprehend right from the wrong. We can decide what is good for us, and what is not. We also have the capacity to control our minds and activities. We can learn about the wholesome religious principles of the Jainism and put them to practice by adopting the appropriate vows and restraints. We can also renounce (give up) worldly life for the monkhood which can lead us to liberation or salvation.
Tiryanch Beings: Animals, birds, sea creatures and reptiles have mind, but the rest of tiryanch (ie. plants) do not have a mind. Therefore most of tiryanch suffers passively. Even animals and birds, etc., who have mind can not think or restrain nearly as much as humans and therefore their progress is compromised. Overall there is a great degree of passive suffering and dependency in their life. The cruel animals accumulate more bad karmas. Their life is not conducive to attain salvation.