re: Variations in Human Intelligence vs Animal Intelligence

short answer, yes there is variation amongst a species.

slightly longer answer. Look at the phylogenetic tree. if you dont know what that is, very crudely, it is like a "family tree" for all species. things at the low end of the tree are simple uncomplicated creatures. The higher on the tree you climb, the more "Evolved" or complicated a species is. Humans would be at the apex of the tree.

i think as you climb up that tree, you see more variations amongst a species in individuals. For for example, a chimpanzees probably have a higher degree of variation, and, you will find "smart" chimps, and "dumb chimps". the lower on the tree, i find the more uniform species become. one roach is basicaly no different than another roach.