The photographer involved should have set himself up as a stock agency for marketing monkey selfies. After all, the ape does not have the ability to market any shots it took and as marketing and promotion are the most important aspects of 'monetizing' any image, the agent can retain 90% of the royalties earned with the remainder going into a special royalties 'fund' for the ape.
When the royalty fund has built up to a sufficient amount, the agent (photographer) undertakes to use the money from the fund to give it to the monkey in a form which the beast can use (ie food).

So, every couple of years the photographer flies back to the original location (all expenses paid from the fund) with a couple of big bags of nuts or whatever the ape most likes to eat. And they all live happily ever after.....until the ape dies and you have to discover its descendants to whom the fund royalties have to be paid/fed in perpetuity.

The big question is: who will sign the model release?

Well, that animal selfie was far better than any selfie I've managed to do.