For thousands of years, Egypt had a major trading partner known as Punt. Although the significance of Punt as a source of gold, ivory, and exotic timbers was well recorded, its exact location has been a mystery. Now that may have been solved, thanks to some mummified baboons.
Egyptian records show a major trading expedition to Punt 4,500 years ago, and it appears gold had made its way between the kingdoms even earlier. Expeditions to Punt were celebrated in Egyptian art over thousands of years and form the basis of one of the oldest surviving hero's journey tales. The route there, however, is unknown, and historians have debated whether Punt lay in the Horn of Africa, Arabia, modern Sudan, or some mixture of all three. This uncertainty has not prevented part of modern Somalia from adopting the name Puntland.
Among the items Egyptians recorded as coming from Punt are baboons, considered the embodiment of Thoth (a god of wisdom, writing, and the moon) and mummified by the Egyptians when they died. In 2015, isotopes from two of these baboons were sampled to try to identify their origins in the hope this would resolve Punt’s location. Although the results were consistent with origins in Ethiopia or Eritrea, they were not considered definitive.
Now, the first author of that study, Professor Nathaniel Dominy of Dartmouth College, has conducted a more detailed investigation using the same idea. Dominy collected oxygen and strontium isotopes from 155 baboons from 77 locations across northern Africa and Arabia. These were compared with the isotopes of mummified baboons.
The food we eat and the water we drink can have a ratio of isotopes specific to the area it comes from, which literally becomes incorporated in our bones. Today, food shipped from across the world blurs the picture, but in ancient times it was different, for baboons as much as humans. Bone and hair strontium indicate where someone lived in their last years before death, while teeth isotopes can identify someone's childhood home.
In eLife, Dominy and co-authors report that five mummified baboons dating from 2,000-2,400 years ago were raised in Egypt, presumably in a captive breeding program. However, two baboons dating from up to a thousand years earlier have isotopes consistent with having lived in an area that covers much of what is now Ethiopia, Eritrea, and Djibouti. Parts of Somalia and Yemen have similar isotopic ratios. One of the pair had not been outside this area long before it died and was mummified.

The finding is in line with the most popular theory that Punt covered modern Ethiopia and some parts of the horn of Africa, although it does not completely rule out one alternative theory placing it in Yemen.
The Egyptian-Punt trade relationship was so ground-breaking some historians have referred to it as the start of economic globalization, although we know from the movements of shells and carvings that long-distance trade has been occurring for tens of thousands of years. To our eyes, the distance from Egypt to Eritrea may seem a modest journey, but some historians have questioned whether Egyptian ships, developed for sailing on the Nile, could have gone this far in the Red Sea. “Many scholars view trade between Egypt and Punt as the first long maritime step in a trade network known as the spice route, which would go on to shape geopolitical fortunes for millennia,” Dominy said in a statement.