Just like the human versions, nonhuman primates are social creatures. They clean each other, cooperate with each other, help each other with eating. This year, a few studies added even more to what we know about primate relationships, and indeed, science has been investigating this topic for quite some time. In 1991, the journal Lab Animal Science published a study on the topic titled “Social interaction in nonhuman primates: an underlying theme for primate research.” And then more than a decade later, a 2002 paper discussed the use of the “f-word” (aka friendship) in primatology. In the paper, primatologist Joan B. Silk, writes that using friendship to describe primate relationships is a possible “backlash against what some researchers see as a narrow-minded preoccupation with the negative aspects of animal behavior, such as competition, conflict, manipulation, coercion, and deception.”