Historical inheritance systems are different systems of inheritance among various people. Detailed anthropological and sociological studies have been made about customs of patrilineal inheritance, where only male children can inherit. Some cultures also employ matrilineal succession, where property can only pass along the female line, most commonly going to the sister's sons of the decedent; but also, in some societies, from the mother to her daughters. Some ancient societies and most modern states employ egalitarian inheritance, without discrimination based on gender and/or birth order. Land inheritance customs greatly vary across cultures. The Ethnographic Atlas gives the following data regarding land distribution: primogeniture predominates in 247 societies, while ultimogeniture prevails in 16. In 19 societies land is exclusively or predominantly given to the one adjudged best qualified, while equality predominates in 301 societies. Regarding land inheritance rules, in 340 societies sons inherit, in 90 other patrilineal heirs (such as brothers), in 31 sister's sons, in 60 other matrilineal heirs (such as daughters or brothers), and in 98 all children. In 43 societies land is given to all children, but daughters receive less. In 472 societies, the distribution of inherited land follows no clear rules or information is missing, while in 436 societies inheritance rules for real property do not exist or data is missing; this is partly because there are many societies where there is little or no land to inherit, such as in hunter-gatherer or pastoral societies. Patrilineal primogeniture, where the eldest son inherits, was customary among many cultures around the world. Patrilineal ultimogeniture, where the youngest son inherits, was customary among a number of cultures including: Fur, Fali, Sami (also called Lapp), Bashkir, Chuvash, Gagauz, Vep, Tatar, Achang, Ayi, Atayal, Kachi, Biate, Chinantec, Hmar, Mro, Kom, Purum and Lushei or Lushai (sometimes mistakenly taken for the whole Mizo people, especially in the past).