section_path: Non-human friendship
section_name: Non-human friendship
paragraph_text: Non-human friendship
  
  Friendship is found among animals of higher intelligence, such as higher mammals and some birds. There is ample comparative animal research on the existence of friendships, or the existence of similar forms of relationships, in animals. The function of these relationships in non-human animals appears to primarily be for forming and solidifying alliances for a wide range of fitness and survival reasons. Across a range of non-human animal species, alliances are formed for protection, competition over reproductive access to receptive mates, as means to seek social comfort, solidify social bonds, and to thwart diseases. An expansive meta-analysis examining grooming behaviors in 14 different primate species found that grooming behaviors elicit different types of benefit exchanges, such as support and aid for future intra-species conflicts. Male bottlenose dolphins use synchronous surfacing to determine membership of other potential male allies while female bottlenose dolphins use gentle contact behaviors (i.e., touching behaviors) with other females in response to harassment from males. Female spotted hyenas, whose groups follow a very strict dominance hierarchy, form alliances (i.e., coalitionary bonds) to move up the dominance hierarchy by usurping a hyena of higher dominance rank. Feral female horses develop alliances with other female horses to avoid harassment from male horses and these alliances aid in increasing their offspring's chances of survival.