"In his opening chapter, “Birth”, Varese compares the initiation rituals that are common to almost every mafia organization. He draws from interviews, autobiographies and police wiretap transcripts in which the gangsters do most of the talking. It is remarkable how close in style, substance and imagery the initiation ceremonies are across cultures – the religious symbolism, the use of tattoos, the omertà, the misogyny and sealing of membership through blood are present among the Yakuza of Japan, the Russian mafia, the Chinese triads and the Sicilian Mafia."
It seems to me mafias are basically tribal societies. That is not surprising as human psychology is basically designed for tribal existence. With complex civilized societies, humans are expected to integrate into something much larger than a simple tribe. However, civilizations often have spaces in which tribes can start up and survive, such as cults and criminal mafias.