In Custom Settings Menu:
a1: AF-C Priority Selection
a2: AF-S Priority Selection
For both the above, You have 2 options 1) Release 2) Focus
My recommendation is to keep it in Release.
1) Release - The photo can be taken when the shutter-release button in fully pressed.
2) Focus - Photo can be only taken when the camera feels that it has achieved focus.
The problem with second option is that, depending on multiple factors, the camera may hunt for sometime to achieve proper focus. There are situations where you know you have achieved focus, but the camera thinks otherwise and will not click.
This is frustrating and you miss your shots. With the release option, once you believe you have achieved focus, just click and take the photo.
In this case of Orangutan swinging, with the busy background, the camera + lens combination may take time to achieve focus and you may miss the shot.
Similar one exists for Canon users which I will convey soon.