Nepotism and the “self-domestication” hypothesis.

Spotted hyenas are the most successful carnivores in Africa, characterized by a social structure similar to primates and a very unique socio-biology. For these reasons, they are one of the most interesting animals for studying social intelligence and may provide valuable insights into how to promote cooperation within groups.

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Spotted hyenas are the only species among the four that constitute the Hyaenidae family to live in a complex society, one so intricate to have more in common with many primate societies than with other carnivores.

Spotted hyenas live in multi-male, multi-female clans that can include up to 130 members, around 50 adult females, 40 adult males, and 40 offspring. All group members are familiar with one another, even though the entire clan rarely congregates, to reduce feeding competition.

The clans are led by an 'alpha-female' and organized by strict linear dominance hierarchies. An individual’s position in the hierarchy is determined by the social rank of their mother. Daughters and sons "inherit" the social rank of their mother, following a nepotistic model observed in some primates.

Learning one’s rank within such a large group requires a substantial memory for individuals and a significant capacity for social learning.

Most of this learning occurs at a communal den, the focal point of social activity for all group members, where all juveniles reside until they are 8–12 months old and where cubs learn their social ranks within the group. In essence, it is like spotted hyenas taking their cubs to kindergarten without wearing a uniform but highlighting social differences to ensure that the young will learn who belongs to whom.

Daughters typically remain in their birth clan for life, building close relationships with their mothers and sisters. This coalition system reinforces the social rank of individuals within the clan hierarchy. Therefore, coalitions and clan hierarchies usually remain stable for many years. However, when the reigning coalition of the alpha female and her allies weakens —such as when an ally dies or the females in the coalition do not reproduce well —a coalition of lower-ranking females may overthrow the alpha female coalition.

To avoid inbreeding, all males disperse at about 3.5 years old to join a new clan. Upon joining a new clan, a male acquires the lowest social rank, regardless of the rank he holds in his birth clan. It usually takes immigrant males many years to reach the top of the male hierarchy. This creates a society in which adult females and their cubs are dominant over all adult male immigrants, a notable difference from primates.

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Contrary to popular belief, hyenas usually hunt alone, though they will opportunistically scavenge. Once prey is captured, however, many group members typically converge on the carcass to feed, leading to intense feeding competition where social rank determines priority access to food.

According to popular belief, female spotted hyenas are very aggressive, and their social behavior and physical characteristics result from natural selection for this trait. In conditions of limited resources, mothers promote siblicide — where one cub kills another — to ensure the survival of the most aggressive individuals. This strategy strengthens the aggressive trait in future generations. The oddest consequence of selecting individuals with the highest testosterone levels is the masculinization of the external sexual organs of female spotted hyenas, making males and females almost indistinguishable.

This selection process for aggressiveness in hyenas is the cue to introduce a highly regarded hypothesis in anthropology suggesting that humans are a "self-domesticated species" that have reduced their levels of aggression.

In essence, this theory asserts that over time, humans have developed social mechanisms favoring the selection of less aggressive and more cooperative individuals. An intuitive example is the prison system for the most unruled individuals, which isolates them and prevents them from reproducing and passing on their aggressive traits.

The medieval period was particularly lethal, with human-on-human violence accounting for 12% of recorded deaths. However, over the last century, the homicide rate has decreased globally by 1.33% per year, and in the least violent parts of the world today, it is lower than 0.01%.

To understand this path to civilization, we must consider that in some primates, 2% of individuals die in conflicts with members of their species, corresponding to the estimated killing rate in Paleolithic humans.

Regardless of how violent or peaceful our origins were, we can modulate the level of interpersonal violence by changing social rules.

Therefore, the level of cooperation and competition in a community is strongly influenced by social rules, which determine what is acceptable or not within that community. This mechanism, based on an action-feedback model, allows for the gradual convergence toward desired behaviors within a community, such as a team or a company.

The speed at which individual behavior tends to conform to the desired behavior is influenced by a combination of genetic traits and social learning according to the 'nature-culture' paradigm.

In a clustered network like a company, the Recruitment and Learning & Development departments can work together to select more cooperative employees (nature) and use the levers of education and reward systems (culture) to promote cooperation. This mechanism can virtually work for the diffusion of any type of behavior, which gradually spreads as it is recognized as successful behavior.

Main references:

·????? H.E. Watts and K.E. Holekamp - Hyena societies (2016)

·????? J.M. Gomez et al – The phylogenetic roots of human lethal violence (2016)

·????? R.W. Sussman – Humans may not be as aggressive and competitive as thought (2002)