Female and male primates often form close bonds, but not purely out of affection. Close relationships usually evolve when there is a clear benefit for both parties, with protection and reproductive control playing key roles. Female and male primates often form close bonds, but not purely out of affection. Close relationships usually evolve when there is a clear benefit for both parties, with protection and reproductive control playing key roles. Plants & Animals Evolution Phys.org – latest science and technology news stories