I'm a big advocate of back-button focus for nature photography, and I always suggest that my workshop clients try it out. Back-button focus completely decouples auto-focus from the shutter button. Auto-focus is activated only by pressing a button on the back of the camera that is now dedicated to this function. It's a real boon for rainforest wildlife because acquiring focus initially can be difficult with subjects hidden in lush vegetation. There are lots of potential things for the camera to focus on so you don't want your camera trying to refocus every time you take a picture of a monkey or toucan. You'll lose lots of shots this way, and this is precisely why back-button focus makes so much sense for tropical wildlife photography. I've been thinking of writing a blog post on the subject, but Canon's Rudy Winston does a great job of explaining all about it here. Note that these days, this function can be most easily set on Canon cameras via the Q menu using the custom controls icon. The way to set this up back-button focus on Nikon is a bit different but it's just as easy and works the exact same way once you have it configured.
If you haven't used back-button focus for your photography, try it out!