★ EGG
Ameiuns eggs varies form, shape and size from the element they are.

★ CUB
Cubs are very little (Big as a human palm), they are blind and have very thick fur that covers their body, they don't have ears (They do have ear-holes, but are covered in fur), they are not able to walk as they didn't develop their back paws and have huge front paws. 
They do not talk, they however makes squee noises whenever treathened.

★ PUERI
Ameiuns in the Pueri's stage, develop half-back paws and their front paws got re-sized. 
They have less thick fur, but have more fat in their stomach and lower back, making them unable to walk properly. 
(They do walk, but fall and trip very often)
They develop little ears, and gain some eye-sight, although remain nearsighted until the Atum's stage.

★ ATUM
This is the stage where they can walk properly and starts to fly/float. 
Their paws and eye-sight are fully developed; their fur is well distributed as well with body-fat. 
(They are a little chubbier than the adult stage though.)
Their ears, tails and body is growing, and they are developing their termo glands. Which will make them able to float trough space, for a little time, in this stage.
This is also the stage where their lacrimal gland activates, they might starts crying for no reason out of nowhere, and might have sudden growth of their elements around their body. (Depending on their rarytness)

★ ADULT
Adults Ameiuns, are fully developed, they can start travelling trough space. Their body, ears and tails finished to grow.

★ ELDER
Old Ameiuns starts losing their fur (patch-wise) and their ears drop down. They get tired very easily, most of them stops travelling,
and so become caretakers of eggs and cubs. 
Elders are also really fragile, and might develop osteoporosis.

★ ASH
And here we get to an Ameiun's death. 
When an Ameiun perish, their body becomes ashes which in contact with the ground grows a part of that Ameiun's element. 
(Exemple, if an Ameiun's element is roses, they will leave a rose growing on the ground.)