I have heard from a Buddhist monk that hungry ghosts usually return to their familis searching for food, which makes me believe they have easy access to memories of their previous life. Some hell beings also know what they did to deserve their punishment (according to what I have heard) so they have access to memories as well, I'm assuming devas should know it too.
Apparently only Humans and animals do not remember previous lifes, is there a reason for that in the teachings?
All the beings you mention as remembering past lives are spontaneously reborn (opapaatika), whereas humans and animals are either egg-born (aṇḍaja), womb-born (jalābuja), or moisture-born (saṃsedaja). Only spontaneously reborn beings are readily able to remember their past lives; most others have their past life memories repressed by the trauma and general coarseness of their rebirth.
I know this is all general Buddhist knowledge, but I can't find a reliable source from the original texts; if anyone knows of one, please feel free to put it in the comments.
All the beings you mention as remembering past lives are spontaneously reborn (opapaatika), whereas humans and animals are either egg-born (aṇḍaja), womb-born (jalābuja), or moisture-born (saṃsedaja). Only spontaneously reborn beings are readily able to remember their past lives; most others have their past life memories repressed by the trauma and general coarseness of their rebirth.
I know this is all general Buddhist knowledge, but I can't find a reliable source from the original texts; if anyone knows of one, please feel free to put it in the comments. - Ven. Yuttadhammo
This is in reference to Ven. Yuttadhammo's answer.
"Sariputta, there are these four kinds of generation. What are the four? Egg-born generation, womb-born generation, moisture-born generation and spontaneous generation.
"What is egg-born generation? There are these beings born by breaking out of the shell of an egg; this is called egg-born generation. What is womb-born generation? There are these beings born by breaking out from the caul; this is called womb-born generation. What is moisture-born generation? There are these beings born in a rotten fish, in a rotten corpse, in rotten dough, in a cesspit, or in a sewer; this is called moisture-born generation. What is spontaneous generation? There are gods and denizens of hell and certain human beings and some beings in the lower worlds; this is called spontaneous generation. These are the four kinds of generation.
(Maha-Sihanada Sutta, MN 12)
You can refer to : http://www.accesstoinsight.org/tipitaka/mn/mn.012.ntbb.html
