If each parent contributes only one gene of its pair to the offspring, the parental genes of Gg x gg would produce the following offspring: Gg or gg. Gg would appear gray while gg would produce black fur. The first cross would produce only gray squirrels since one parent always gives a G, masking the g given by the other parent. The second cross only has G so all offspring would have to be gray, and the last cross would not produce any gray squirrels since there are no G.