12:09 AM, Tuesday May 19th 2020
They are pretty big. The exact size doesn't matter much, as the objective on this lesson is to make a solid 3d drawing, it doesn't have to be 100% accurate to the reference.
So the main thing you should be looking at when drawing the eye socket and other features of the heads of animals, is not about their exact size, but about how to draw them so they fit snuggly on the head as if it was a puzzle.
So, instead of worrying about the exact size of the eye socket, try to think of it as a piece of a puzzle on the head, make sure it doesn't stay floating on it. (Also, to get an idea about how big eye sockets are, you can check images of the skull of the animal you're drawing)