Identification
Which species of monkey or ape Jacco belonged to is unknown. Lennox initially describes him as coming from Africa, but later writes that he belonged to the Asian gibbon family:
Jacko was of that species of Simiae denominated the Gibbon, which sit with their forepaws upon the ground; he was of a cinerous or ashy colour, with black fingers and muzzle. ... In appearance he was neither old nor ugly.
Egan describes him as the "famed Italian monkey", Umberto Cuomo writing in Il Bulldog in 2002 says he was probably a mandrill. Before Aistrop had acquired Jacco, he had featured a baboon at the Westminster Pit in an attempt to capitalise on Jacco's growing fame, but, according to Lennox, this had only served to emphasise Jacco's skill by comparison. Neither the Cruikshanks' aquatint nor Henry Aitken's depiction of Jacco fighting an unidentified opponent are detailed enough to identify Jacco's species, even if they are taken from life (the Cruickshanks are more interested in depicting the spectators than in the accuracy of the depiction of the monkey). Landseer's etching shows Jacco with a short tail and is annotated with "...from a sketch made at the time by himself", so it is liable to be the most accurate of the illustrations of Jacco. Aistrop described Jacco as "canine mouthed and much larger than the common monkey".
The term Macacco was in use as a general term for a monkey at the time; it came from the Portuguese macaco meaning "monkey," a derivative of a Bantu word that had been exported to Brazil where it was used to describe various type of monkey in the 17th century. As different authors applied the term to different species it is difficult to know which species, genus or family was meant. Macaca was given as a name to a widespread genus of Old World monkeys (the macaques) in 1799. Jaco was the specific name for a lemur and the term "Macauco" was also in general use to mean lemur, but there is no suggestion that Jacco was a lemur — Lennox specifically discounts this, and credits Jacco's forename as deriving from the "Jolly Jack Tars" that transported him to England and first observed his fighting abilities. Jacco's fame may have been associated with the rise of a Cockney slang word for a monkey "Murkauker" in the middle of the 19th century (although this was already obsolete by 1890s), and "Jacco Macacco" itself was at least sometimes used as a generalised term for a monkey at the same period. Aistrop claimed that the sailor that had originally owned him had taken him from the "Isle of Maccacco".
Read more about this topic: Jacco Macacco