It is important to keep in mind what kind of slave vessels these records are taken from. These are, generally speaking, Portugese and occasionally French ships intercepted by the Royal Navy. The 1820s represents the pinnacle of the transatlantic slave trade. Between January 1st 1820 and December 31st 1829, a person was taken against their will from the West African cost on average every 1.6 minutes, every single day, every single week, every single month, every single year, without interruption for the entire decade. But Britain had outlawed the slave trade in 1807, though slavery remained legal in her colonies until 1833 and was not fully abolished until 1838 (and 1843 in India). We know that in the French, Spanish and Portugese slave trades there was a disproportionately strong preference for purchasing younger people on the West African coast in the cold, calculating hope that they would represent longer-term investments to prospective buyers, and this strong preference is likely reflected to some modest extent in the data. Younger slaves would have been more easily 'marketable' as clearly young and not simply youthful-looking adults.

For the most part however, the short and simplest answer is probably that the age data is simply unreliable due to sloppiness in the original production of records. In the course of the transatlantic slave trade, height was frequently used as a proxy for age - individuals under a certain height were assumed to be children and all those over were taken to be adults - and there was not very much concern for figuring out the exact age of any of the trade's victims. Where age was used, enslaved people would generally be divided quite plainly into those aged under 15 or aged 15 or older, with 15 being taken to be the age of adulthood. Whilst the Transatlantic Slave Trade Database is the single best and most accurate data source you will ever find for the scale of the slave trade, the African Names Database within it is riddled - because of faults in the original documents and not the efforts of its creators - with errors. For example, there are about 120 individuals with heights that indicate they cannot be adults who are listed with ages ranging from 16 to 40.

For example, if we take a look at the roughly 4,200 individuals listed in the Names Database with an age of 20 years old, we'll get an average height of 61.4 inches, or a little over 5ft. If we take the 14 and 15 year olds, we get an average height of 57.1 inches, or between 4ft7 and 4ft8. Among our 20 year olds we have 491 - about a tenth - recorded with a height below the average height for a young teenager, and among our young teenagers we have 294 - again about a tenth - with a height over the average height of the 20 year olds. Now of course, these kind of variations in height happen. Some people are simply taller or shorter than others. But in general, we cannot accurately rely on the age data in these records. It is often a guess or an estimate or an error in recording. At the 14 - 18 age bracket, this is simply probably where the bulk of the error in transcription falls as different growth rates in individuals confuse recorders who. We find different records of slave trading produce wildly different age distribution trends depending on the country and location and whilst some of this will reflect genuine variation, it is also simply error on the part of the enumerators.

Although it predates this data, David Geggus discusses some of the factors that shaped age profiles of the slave trade in "Sex Ratio, Age and Ethnicity in the Atlantic Slave Trade: Data from French Shipping and Plantation Records", The Journal of African History 30, no. 1 (1989): pp 23 - 44.

Source: https://www.instagram.com/visyuval/

Data: https://www.slavevoyages.org/resources/about#african-names-database/0/en/

During the last 60 years of the trans-Atlantic slave trade, courts around the Atlantic basins condemned over two thousand vessels for engaging in the traffic and recorded the details of captives found on board including their African names. The African Names Database was created from these records, now located in the Registers of Liberated Africans at the Sierra Leone National Archives, Freetown, as well as Series FO84, FO313, CO247 and CO267 held at the British National Archives in London. Links are provided to the ships in the Voyages Database from which the liberated Africans were rescued, as well as to the African Origins site where users can hear the names pronounced and help us identify the languages in which they think the names are used.