Much shorter than the Tall Greys, the height of Grey Hybrids is only approximately four feet.

They appear to have been a species designed by Galactic Federation scientists, derived from a blend of Tall Grey and Human genetics.  Highly intelligent, long-lived and displaying noticeably more emotion than their Zeta forebears, these beings are capable of outbursts ranging from humor to impatience and ire.  They are often considered the perfect diplomatic envoys to Earth and other planets in the Quarantine, as they possess an increased ability to handle high-gravity environments, as well as a Nitrogen-Oxygen atmosphere. Hybrids also possess well-developed vocal cords, though they still prefer to rely heavily on telepathy to communicate. 

Per our records, they have never forged any ties with the Monmouth Project.