Births due to karmic sins

Will not dwell much into Karma , its logic ,its effects , will keep that for another post.
Simple starter for someone who is interested . The soul, when it assumes a human body, experiences life by performing various actions . Some people ask why does the soul have to do it , its because eating a chocolate is more tangible and satisfying than just the thought of it.. hence the soul needs a body to eat it :)

BUT when the soul resides in a human body , it might perform tasks that it was not originally intended to.( Human form is the highest form and the only form that can make irrational choice). For the people who belive in cause and effect theory , Soul cannot simply get away staring a chain .. it has to bear the effects .. this is called the soul cleansing ... NOW come the interesting part , the soul inorder to have a human life again , will have to have a clean slate... the below quotes are from "Manu Smrithi" a fantastic book.

After residing in a human body , the soul will have to pay for its acts by residing in other low life forms and bearing the consequences of its act before it can be reborn as a Human again. Here are some of the life forms that you will be born as based on the sins that you commited

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Act - Life form
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One who steals - Ant and other small insects

One who steals water - Aquatic Animal

Land Grabbers - bamboo, Creepers, Bushes

One who sleeps with Women of Same - Bear
Gotra(Basically a close relative)

One who steals food item and eats without - Cat
sharing them

One who roams around with Physical cleanliness - Crane
but is dirty to the core of heart. people who cheat

When a person eats food without being invited - Crow

Drunkard and wayward - Dog

One who equates himself with Lord, insults learned- Pig
person, kills a Brahman

Donation is taken from a sinful person to do Holy - Donkey
work. Illicit relationship

Person who commits crime without any inner - Fish
consciousness

One who promises some donation and forgets it - Jackal

One who cheats whill buying - Owl

One who sleeps with a girl who is not mature yet - Python

One who commits suicide by consuming poison - Snake

One who insults parents and not serve them in - Sparrow
old age

One who steals perfume - Squirrel

Steals meat, begs borrows money and not utilize - Vulture
it for the purpose taken for

Note that the low life forms usually dont commit additional karma , because unlike the human form, they have standard behaviour and they do what they are supposed to do .. no deviations and hence no unwanted effects :)

Please note , the above life form is in addition to 1 year of Hell that the person has to go through.
After a person dies , there is a concept of "Pinda Dana" in Hindu Mythology , This is basically food is provided for the soul of the departed for ten days , so that it can create a virtual Human life form , which is then subjected to one year of hell in order to cleans itself.

If the pinda dana is not provided , the soul cannot complete the creation of virtual human form and hence never cleanse itself.Hence these souls wander and remain as Ghost , Bhoot , preta as they are unable to clean up their act nor proceed further

... interesting :)

One year of Hell is itself another post .. that will be coming soon