They are not, strictly speaking, reptillian but mammalian humans who have devolved back into reptillian lifeforms to live in deep space. Some (not all) come from a planet called David that was once in the same orbit that our Earth is currently in. The Hopi Nation refer to them as the 'egg layers' or 'red eyes' because they are cold blooded, cannot regulate their body temperature (they have no thyroid glands) and are hatched not born live like we are. They were all once human like us but 'ate the fruit of the forbidden tree' which is living in space/time. It's a long story:

[link to dancingawakethefifthworld.com]