Step 10: Draw a long, wavy, horizontal line below the nose for the mouth. The mouth should stretch the width of the initial small circle. Curve the left side to connect to the nose. Curve the middle part up a bit. When you get the shape right, darken the line. Pay attention to the distance between the gorilla's nose and mouth. Use the initial shapes as guides. Draw a series of short strokes along the edge of the small initial circle for the hair on the chin. Draw a row of short lines under the mouth to emphasize the lower lip.
Step 11: Draw a series of short strokes along the left side of the ear guide for some hair. Darken the guide for the ear but make the shape a bit more angular. Part of the gorilla's ear should be hidden behind hair. Draw a few lines within the shape for the inner ear structure.
Step 12: Draw a series of strokes around the gorilla's eyes and nose for the hairline around the face. The slopes on the sides should slope inward toward the nose. Don't make the individual strokes too long, otherwise the hair will be too shaggy. Draw more short strokes high above the eyes for the hairline just above the thick brow. Use the initial circle and arc as guides to draw the hair around the lower half of the head. Draw a series of short strokes along the outer edges of the initial guides to draw the lower half of the head. Curve the path of the strokes on the left to make the shape of the fur wider. Dip the strokes along the bottom lower than the guide for the gorilla's beard-like hair. Follow the path of the guide on the right to finish the hair along the jaw. Don't draw the strokes too close together; leave some space between them.
Step 13: Use the tall arc at the top as a guide to draw the rest of the gorilla's head. Draw a series of short strokes along the basic path of the guide to create the shape of the head. When you get to the right side, draw the strokes so that they slope to the right to create part of the neck. Add more strokes along the right edge of the initial arc. Add some strokes in the shape of an arc above the first circle to emphasize the dome-like head.
Step 14: For a cleaner look, erase as much as you can of the initial guide lines. Don't worry about erasing all of the guides. It's okay to leave some behind. Re-draw any final sketch lines you may have accidentally erased.
Final Step: Add some shading to your gorilla drawing for extra detail. Use a medium value for the irises but don't overlap the highlight circles. Use a dark value to add shadows to the part of the face without hair. Shade lightly at first, and then gradually build up to darker values. Pick the direction of the light source when shading so that the shadows are consistent. Use a dark value in the nostrils. Vary the pressure on your pencil to get different degrees of tonal value. Use short strokes of a medium value to shade the rest of the gorilla's hairy head. For a more detailed guide on how to shade, check out this tutorial: How to shade.
For the top of the head, use strokes that generate outward from the brow. Curve the strokes on the sides so that the hair appears to face back. The strokes at the bottom should be more vertical. Use a smoother and lighter value across the rest of the gorilla's face. Continue shading the head gradually using darker values with every pass. As you shade the hair, separate each individual stroke a bit so that the white of the paper comes through. Shading like this can be very time-consuming, so be patient and take breaks.
Use a light value on the top parts of the gorilla's brow, nose and lips for highlights. It's a good idea to use reference as you draw for a more accurate depiction of a gorilla. The white part of gorillas' eyes is usually dark, so add dark value here too. Don't forget to pause the video after each step to draw at your own pace.