This is the first article in a multi-part series about primate cities.

The recent movie “Rise of the Planet of the Apes” depicts a world where primates of all kinds begin to take control of the world. Funnily enough our world today is in many ways a planet of primate cities — just a different type of ‘primate city’. The term primate city has been used for years not to describe settlements of apes, monkeys, or other primate species, but as a term for cities of outsize importance, significance, or population in relation to other cities within their nation. The term was coined by geographer Mark Jefferson who described a primate city as any city that is more than twice as large and more than twice as significant as any other domestic urban counterparts. Significance is hard to define but this significance is usually attributed to these cities having much larger economies, control over a country’s media production, and often serving as the capital of their respective nation; it is derived from these cities’ ‘primacy’ over all their in-country rivals.

Primate cities are in many ways models of the best and worst aspects of today’s unprecedented urbanization, economic growth, and widening economic inequality. Many of these cities represent the economic hopes and dreams of burgeoning middle classes around the world but they also often become the places where the divide between rich and poor can be seen most starkly.

Upon arrival in Bangkok, Thailand I was told by friends and colleagues that my new home was in fact the world’s “most primate” of cities. However, I was unclear on exactly what makes a city “more” primate than another city and I sought to find more data on this urban trend of cities that come to define entire nations.

As I began researching primate cities I found far less information than I would have expected on the subject. Living in a city known as the world’s “most primate” made me curious about the topic and so I decided to do some research about these places and their role in many of today’s biggest urban trends and dynamics.

To determine which of the world’s cities constitute primate cities, I used Demographia’s population data for the world’s urban areas with populations over 500,000 in 2014. I sorted through the world’s largest 150 urban areas to discern which ones were either the largest or second largest urban areas in their respective countries*. Any smaller cities could potentially be primate cities, but would likely not be large enough to have major significance outside their nations. Any city that had a population at least three times as large as its counterpart was deemed a “primate city”. This three-times-larger rule was used to make up for the lack of data available to measure the second part of Jefferson’s primate city definition: significance.

Fifty of the world’s largest 150 cities were either the largest or second largest cities in their respective nations. The remaining 100, including many in China, India, and the United States, were overshadowed by larger domestic rivals. According to the definition of a primate city as three times larger than its next largest counterpart, 31 of the 50 cities studied were deemed ‘primate cities’. Of these 31 cities, 11 are in Africa, 12 are in Asia, 4 are in Europe, 1 is in North America, and 3 are in South America.

I then used Population Reference Bureau’s 2013 data for current national population numbers for the countries with primate cities. I determined what percentage of each country’s population resides in its respective primate city. With these statistics it was possible to begin thinking about what is “the most primate city in the world” by three different metrics. First is the basic metric of total population size of each city’s urban area – which city has the overall largest population. The second and third metrics are more nuanced; how many times larger the primate city is in relation to its domestic counterparts and the percentage of a given country that resides within its primate city. These three metrics measure primacy in different ways and thus lead to different answers to the “most primate city” question. Below are the top ten ‘most primate’ cities according to each of the three potential primacy metrics:

10 Largest Primate Cities by Population:

Jakarta, Indonesia 29,959,000 Seoul, South Korea 22,992,000 Manila, Philippines 22,710,000 Mexico City, Mexico 20,300,000 Moscow, Russia 15,885,000 Cairo, Egypt 15,206,000 Bangkok, Thailand 14,910,000 Dhaka, Bangladesh 14,816,000 Buenos Aires, Argentina 13,913,000 Tehran, Iran 13,429,000

10 Most Primate Cities by Times Larger than Respective 2nd City:

Bangkok, Thailand – 29.8x larger than Chonburi, Thailand Lima, Peru – 12.7x larger than Arequippa, Peru Addis Abeba, Ethiopia – 11.6x larger than Mek’ele, Ethiopia Khartoum, Sudan – 10.3x larger than Nyala, Sudan Manila, Philippines – 9.0x larger than Cebu, Philippines Buenos Aires, Argentina – 8.8x larger than Cordoba, Argentina Kabul, Afghanistan – 8.3x larger than Herat, Afghanistan Paris, France – 7.1x larger than Lyon, France Santiago, Chile – 7.0x larger than Valparaiso-Vina Del Mar, Chile Dakar, Senegal – 6.5x larger than Touba, Senegal

10 Most Primate Cities by Percentage of National Population in Respective Primate City:

Seoul, South Korea 45.8% Santiago, Chile 35.5% Buenos Aires, Argentina 33.7% Lima, Peru 31.7% Luanda, Angola 26.2% Dakar, Senegal 25.1% Manila, Philippines 23.6% Abidjan, Ivory Coast 22.6% Bangkok, Thailand 22.5% Kuala Lumpur, Malaysia 22.3%

This data reveals a variety of interesting findings. Only 3 cities make it into all three ‘Top 10’ lists: Manila, Philippines; Bangkok, Thailand; and Buenos Aires, Argentina. Even this study, which restricted the primate definition to population differences and did not try to measure ‘significance’, yielded significant variation in primacy rates. The first metric seems to favor cities in relatively populous countries. Jakarta, Indonesia tops this list, but does not show up elsewhere, most likely because being located in the world’s fourth most populous country means there are other sizable population centers striving to catch up to Jakarta’s size. The second list seems to measure domestic primacy most directly, however it also favors countries that simply have thus far experienced very little urban development. For example, Khartoum, Sudan and Kabul, Afghanistan rank highly on this list despite having relatively low overall populations of 5 million and 3.6 million respectively.

This debate and other topics including the history of primate cities, primate cities’ role in domestic political turmoil, primate cities and national economic inequality, and other analysis will be covered in an upcoming multi-part series about primate cities.

*Hong Kong, Dubai, and Singapore were excluded from the data because they can more easily be described as city-states without any potential for domestic urban counterparts.