Triadic Closure Observed in Spotted Hyenas
The concept of triadic closure is part of the foundation of social network and graph theory, and has been studied extensively. Put simply, the triadic closure principle states that two people who don’t know each other are likely to become friends if they have a friend in common. This makes sense for a variety of reasons, including the likelihood of common interests, and the common friend’s incentive to introduce the two strangers to each other.
More surprisingly, it appears that triadic closure behavior is exhibited in some animals in a similar manner as in humans. Recent research done by biologists at the University of Pennsylvania, the National Institute for Mathematical and Biological Synthesis, and Michigan State University indicates some human-like features in the social networks of spotted hyenas.
These socially advanced animals, particularly the males, adhere to a remarkably rigid social structure in which observable bonds exist between certain groups in the clan. Notably, the hyenas tend to be especially socially connected with their mother’s connections, an example of triadic closure. While certain environmental and genetic factors play a role in determining social interactions, the researchers stated that the number one predictor of connections between hyenas is whether or not a mutual connection exists. These “cohesive clusters” have an impact on the process of finding a mate, reproducing, and even surviving.
https://news.upenn.edu/news/making-friends-friends-benefits-hyenas-penn-biologist-finds
https://news.upenn.edu/news/animals-inherit-their-social-network-their-mothers-penn-study-shows