They are to smart to be a big dumb ape. More convincing than that is along with smart, they seem to have a sense of humor. Other than otters and other animals playing, never seen a bear or other animal with a sense of humor playing tricks trying to elicit a human response. The glyph presented to me had symmetry. Symmetry requires some intellect and the glyph a desire to communicate. As far as ET I think it unlikely because of lack of gadgets. But at the same time one cannot completely rule it out until we get DNA and determine evolution of the species.