Much confusion lingering this question!

a scientist observing a group of spider monkeys noticed that the adult females often spend time picking leaves off of tree branches. the scientist hypothesizes that this behavior is caused by boredom. is the scientist’s hypothesis valid?
no, humans are the only organisms that experience boredom.
yes, boredom is a likely explanation for the spider monkeys’ behavior.
no, emotions of non-human organisms cannot be tested.
yes, the hypothesis could be tested through a controlled experiment.