According to a 2012 report called the Corn Comparison Report, GMO corn has 14 parts per million (ppm) of calcium while non-GMO corn has 6130 ppm, 437x more. GMO corn has 2 ppm of magnesium while non-GMO corn has 112 ppm, 56x more. GMO corn has 2 ppm of manganese while non-GMO corn has 14 ppm, 7x more. Furthermore, GMO corn has been shown to have significant levels of chlorides, glyphosate (an herbicide meant to kill weeds), and formaldehyde. According to the report above, GMO corn tested at levels of 60 ppm, 200pm, and 13 ppm, respectively, none of which are naturally found in corn.
I recommend trying your own corn-comparison experiment. Buy ears of both GMO and organic (non-GMO) corn. Find a place nearby that animals can get to and try to secure the corn into the ground with a skewer or stake. Periodically, check the corn and see what gets eaten by animals and what doesn’t. The formaldehyde (used to embalm the deceased) in the GMO corn will likely keep any animals away from it.