To look at this question another way, Aristotle saw ideas as mans collaborative ideas through collective recognition. He did not agree with his mentor Plato. In fact he believed the opposite. For Aristotle, "idea" has no existence of its own. In this sense the idea "gorilla" is simply a concept that we humans had formed after seeing a certain number of gorillas. The idea "gorilla" only came after the sensory "gorilla." 'Gorilla' means "gorilla" because it is conventionally used to express the concept of a gorilla.
So it might seem that there could not be a unified answer to question of what it is for something in general to exist. But Aristotle also thought that there is a connection among these modes of being (or senses of �exist�) which is deep enough to make a unified answer possible. For example, the existence of whiteness is derivative; there is such a thing as whiteness because something, for example some horse, is white. Whiteness is not an independent entity, capable of existing on its own. Gorillas and other biological specimens, on the other hand, are independent entities.
Therefore the unified response to the question is yes, the gorilla is real since we recognise the �idea� that the gorilla is a gorilla as we have formed the idea of a gorilla. The crux of the question however should be: what is real?