Understanding age and size relations are essential if alligators are to be managed effectively. The codes were based upon the number of pigmented patches of black and gray occurring on each of nine tail segments counting forward from the most posterior double caudal crest scutes. These result in a unique code for each side of the tail of each animal. Codes were compiled for 267 'sides' of 190 crocodiles in the Mvuleni crocodile farm and a section of the Oliphants river in Kruger National Park. Left and right sides of each crocodile's tail code differently and each crocodile appears to have a unique pattern of natural marks.
Some difficulty is found in nature as only one side of each crocodile's tail is usually seen.
However, the technique was used with great success with breeding females. At known nest localities both sides of attending females tails could be identified over time. The biggest advantages are that the identifying marks can be observed without catching the animal and that the marks cannot be lost. It suggested a series of recommendations that are being implemented by the Management Authority of Colombia, notably the adoption of a uniform system of marking for skins and manufactured products, and improvement of the knowledge of the status of the crocodilians occurring in Colombia, to allow establishment of more effective management. The conditions of the market for skins as well as that for meat and other products have led the producers of these two subspecies to decide to let the animals grow to sizes bigger than 1.20 cm, to obtain a better profit.