Question: I've just started learning Buddhism, and currently investigating 6 realms of rebirth. What confuses me is that it seems different sources give inconsistent ordering of the realms.

For example, in the book [Buddhism: A Very Short Introduction](https://rads.stackoverflow.com/amzn/click/com/B00BHXVWSS) the 6 realms of rebirth is ordered (from highest to lowest) as follows:

1. Gods
2. Humans
3. Titans
4. Ghosts
5. Animals
6. Hell

However, in wikipedia article of [Saṃsāra](https://en.wikipedia.org/wiki/Sa%E1%B9%83s%C4%81ra_(Buddhism)#Realms_of_rebirth) it presents the following order:

1. Gods
2. Human
3. Demi-god
4. Animal
5. Hungry ghost
6. Hell

I also checked wikipedia for [六道](https://zh.wikipedia.org/wiki/%E5%85%AD%E9%81%93#%E4%B8%89%E5%96%84%E9%81%93) and some other Chinese online articles (since I can read Chinese). It seems they prefer to order demi-god realm above human realm.

So in summary, there seems to be inconsistency of relative ordering of two pairs of realms among various sources, namely the relative ordering between human realm and demi-god realm, and between animal realm and ghost realm.

I'm wondering which is right? Is there a definitive ordering? Maybe different branches of Buddhism define them differently?

Answer: 
The Pali scriptures say:

> 
> Mendicants, there are five destinations. What five? Hell, the animal
> realm, the ghost realm, humanity and the gods. Nirayo, tiracchānayoni,
> pettivisayo, manussā, devā—
> 
> 
> [AN 9.68](https://suttacentral.net/an9.68/en/sujato)
> 
> 
> And what is the diversity in kamma? There is kamma to be experienced
> in hell, kamma to be experienced in the realm of common animals, kamma
> to be experienced in the realm of the hungry shades, kamma to be
> experienced in the human world, kamma to be experienced in the world
> of the devas. This is called the diversity in kamma.
> 
> 
> [AN 6.63](https://www.accesstoinsight.org/tipitaka/an/an06/an06.063.than.html)
> 
> 
> 

Other examples of the above ordering are [here](https://suttacentral.net/search?query=ghost%20animal%20).

Therefore, the ordering of the five realms in descending order is:

1. Gods
2. Humans
3. Ghosts
4. Animals
5. Hell

However, it appears one sutta, from thousands, namely, [Iti 93](https://suttacentral.net/iti93/en/ireland), includes a separate asura realm and places asura below hungry ghosts.

> 
> Being unaware of these three fires, humankind ([pajā](https://suttacentral.net/define/paj%C4%81) = people) delights in personal
> existence.
> 
> 
> Unfree from the bonds of Māra They swell the ranks of hell, existence
> in the animal realm, asura-demons and the sphere of ghosts.
> 
> 
> Iti 93
> 
> 
> 

Therefore, based on Iti 93, the descending order is:

1. Deva gods
2. Humans
3. Hungry ghosts
4. Asura gods
5. Animals
6. Hell
I suspect that both the ones you quoted are correct -- the thing is that, you're assuming that "titan" and "demi-god" are the same, but I don't think they are -- according to this reference to [The Thirty-one Planes of Existence](https://www.accesstoinsight.org/ptf/dhamma/sagga/loka.html), a "demi-god" is presumable a *Deva* (above human) whereas a "titan" is presumably an *Asura* (below human).

As for the ordering of Animal versus Ghost, this reference agrees with Dhammadhatu's answer (based on Pali scriptures). The Wikipedia article you cited explains its reasoning (i.e. that the contrary ordering has an origin in the Tibetan tradition):

> 
> According to McClelland, this realm is the mildest of the three evil realms. According to Yangsi Rinpoche, in contrast, the suffering of the beings born in the realm of the hungry ghosts is far more intense than those born in the animal realm.
> 
> 
> 

Even then I'm not sure what criteria people use to order them -- for example "hungry ghost" might be closer to (more similar to and more akin to, more closely related to) human than the animal realm is, therefore higher in that sense -- even if the suffering of that state is greater, therefore lower in that sense.