depth of field
Aperture is very important in wildlife photography not just because of how much light it captures, but also because of depth of field. At wide apertures like f/2.8, your photos will have a “shallow focus” effect where only your subject is sharp, and the foreground and background are out of focus. At narrower apertures like f/11 and f/16, depth of field increases. This changes the look and feel of a photo, so it’s important to get your aperture right.