Researchers called in three Aboriginal tracking experts to help solve the mystery of these 5,000-year-old footprints. Among the indigenous carvings discovered in the Doronawas Mountains in west-central Namibia, the Kalahari trackers were able to not only identify 407 unique biological footprints, but also calculate the species, gender, and estimated age. Incredibly, the team successfully identified more than 90 percent of the ancient artwork,

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Interestingly, the result is more like a zoo map than an archaeological paper: giraffes, white and black rhinos, ostriches, leopards, spring antelopes, zebras are the commonly depicted species; other species include monkeys, porcupines, jackals, elephants, lions, cheetahs, aardvarks and baboons.

Order Digitally Enhanced Print Puzzle Pastors, Aetal/CC-BY4.0

Overall, at least 40 species can be clearly identified by their unique footprints. More than 60 types of them are bird footprints.

The giraffe won the popularity contest with 54 adult and 81 juvenile footprints. This is an unusual finding in the data, as the data show that carvers focused primarily on adult (and mostly male) footprints.

Animals with fewer than 10 footprints are considered "rare," but researchers don't know the driving force behind species preference Pastors, Aetal/CC-BY4.0

Archaeologists from the Friedrich-Alexander University of Erlangen-Nuremberg in Germany and the University of Cologne in Germany were able to gain a deeper understanding thanks to indigenous trackers from the NyaeNyae reserve in Czenkwe.

As researchers try to piece together the ancient puzzle, they are increasingly relying on these Aboriginal trackers, who often work for the commercial hunters Thui Thao, /Ui Kxunta and Tsamgao Ciqae.

While there are many theories as to why animal footprints appear in our earliest art galleries, and we may never know their full extent, it does provide a valuable record of changes in landscapes and animal populations.

Footprint identification is not foolproof, but it does highlight the importance of unique Aboriginal skill sets to research.

The researchers note: "Namibia's rock walls contain a large number of Stone Age animal and human patterns, as well as human and animal footprints. The latter have received little attention so far because researchers lack the knowledge to interpret them."

The research was published in the journal PLoSONE.