How cute!! Baby monkeys are SO amazing and those hands are so human! You did a great job with the shallow DOF in low light, with the important parts sharp and the rest providing context that doesn't compete for attention.
You might consider removing the green leaf in the lower corner, and cropping from the bottom just enough to get rid of the cut off brown leaves, (or cloning them out) but I'd leave the one right by the fingers.
Love the composition, and I notice with great delight that Mom is holding the tail of the little one, as if to keep him from getting into trouble!
Diane has already given you some good advice, just wanted to add that I would do another round of sharpening on the little one's face, just a tad. Indeed shallow DOF worked wonders here, do not know your equipment and how it handles high ISO but I would have pushed it a bit for more Shutter Speed, just to be on the safe side, since the baby was moving.
Lovely work, the pose is superb and this is a very special image, I truly enjoyed viewing, TFS
So adorable. the eyes and hands say so much. I agree with Diane and would also add removing those two whitish areas of the baby's shoulder. Great capture!