Photographing in jungles is hard. There is stuff in the way, and the light is either dim or seriously contrasty. So you have to compose carefully and really watch your lighting.
With this little capuchin monkey in Costa Rica, I had to add a little fill flash to balance the bright mid-day sunlight backlighting him through the forest canopy. I held the flash off to the side to give it a little bit of direction and I zoomed the flash so that only the monkey would get “flashed). I hate shooting with a flash directly on the camera and I did not want to light up all the foliage.
White-headed capuchin monkey, Manuel Antonio National Park, Costa Rica. Canon 1Dx. 31mm. ISO 400. f/5 @ 1/500 sec. Fill flash (off camera).