The smart play is to kill the monkey

I would have killed the monkey after I used it to discover water and food. It was simply using too many supplies, and you have to think long term. That monkey was eating constantly! Really, how long would those martian sausages last with that little monkey nonstop conveyor belting those things?

And you have the problem of keeping the water supply sanitary, which would be a huge problem with a filthy monkey near the source, eating and defecating all over. You wouldn't know if the monkey contaminated the water until it was too late and you were puking and running a fever, about to die.

It's not the monkey's fault, it's just being an animal. It has instincts to survive like an animal, which is to eat food and drink water. They don't have off switches, so this monkey would continue to eat every day all day until the food depletes. But, because of this, Robinson would necessarily have to kill the monkey, to extend his own life.