Blotches reveal age

A long neck and a coat covered in spots: these are the most noticeable characteristics of the giraffe. Each of these animals has a unique pattern of blotches, and each subspecies is characterised by a different blotch shape and colour.
These blotches can be used not only to identify individuals; in male giraffes, they also tell a story about the animal’s age, as the blotches darken through the years.
Researchers from England, Zambia and Japan studied 33 years of data on 36 male Thornicroft’s giraffes, a subspecies in Zambia. The blotches give a good indication of a giraffe’s age, as they change colour over a period of approximately 1.8 years; the blotches on males of approximately 9.4 years old are completely black. Thanks to the colour changes, the researchers were able to determine the average age of death. Males live to be an average of 16 years, and the maximum age is 22 years. Females live longer, reaching a maximum of 26 years of age. The investigators assert that this giraffe longevity data is more reliable than short-term studies or studies on animals in captivity.

The results of the study were published in the Journal of Zoology.

The giraffes on the picture are not Thornicroft's giraffes.