Gen 6:4 There were giants in the earth in those days; and also after that, when the sons of God came in unto the daughters of men, and they bare children to them, the same became mighty men which were of old, men of renown.
Human (sons of God) + Neaderthal (daughters of men) = Cro Magnon (Giants)
The intent for this mixing was the same as the Nephites and polygamy. Humans wanted many wives and children as workers. However, the Hybrid children couldn't be controlled. They became "men of renown".
7 And the first beast was like a lion, and the second beast like a calf, and the third beast had a face as a man, and the fourth beast was like a flying eagle. (New Testament, Revelation, Chapter 4)
The 3rd beast has a face of a man but Joseph Smith is told it is an animal (Neanderthal)?
Q. Are the four beasts limited to individual beasts, or do they represent classes or orders?
A. They are limited to four individual beasts, which were shown to John, to represent the glory of the classes of beings in their destined order or sphere of creation, in the enjoyment of their eternal felicity. (Doctrine and Covenants, Doctrine and Covenants, Section 77)