“With best friendship there tends to be intimacy, a feeling that the other person is there for you, that they have your back,” says Rebecca Graber, a psychology lecturer at the University of Sussex, in the UK. “It’s about perceived support rather than actually showing up.” However, are we pre-programmed to have best friends?

According to research, developing such close social bonds with others has significant evolutionary benefits. On the other hand, the nature of such bonds can vary widely, and understanding this variation can bring a lot of comfort and hope to persons looking for a best friend but having trouble finding one. Dolphins, like humans, form bonds with one another based on shared interests. In a 2019 study, male dolphins who “sponge” for food in the deep seas primarily interact with other male spongers. These profound links, according to Manuela Bizzozzero, a researcher at the University of Zurich and the study’s lead author, can last for decades and are critical to each male’s mating success.

A 2003 study led by Princeton University primatologist Jeanne Altmann states that friendships among female adult baboons increased their children’s chances of survival. Female baboons with strong social ties are less stressed, according to another study, and when a close partner is killed by predators, females strive to create new associations.