How to draw a gorilla in 3 easy steps.
1) Be born with a certain amount of artistic talent.
2) Practice, practice, practice.
Okay, I lied about the steps being easy. But even having the talent and the practice will not get you a good gorilla drawing. For that you will need an actual gorilla to pose for you. Herein lies the problem. Gorillas don't like you making eye contact with them. If you do it to a wild gorilla you might be in danger. If you do it to a captive gorilla he'll just wander off (or escape and attack you). Either way, no posing gorilla.
The solution? Don't make eye contact with the gorilla. Hence step:
3) Get yourself some Gaze-averting glasses
The sketch is by James Gurney whose technique of avoiding eye contact allowed him some up close contact with both gorillas and chimpanzees.
He watched me draw with a professional interest. Every ten minutes or so he wanted me to show him how I was coming along on the sketch.