By David Malakoff
It helps to carry a machete — and an umbrella — if you are doing archaeology in Sāmoa. The South Pacific archipelago, which includes six islands that comprise the United States territory of American Sāmoa and several islands — only a couple of which are inhabited — of the independent nation of Sāmoa, is soaked by up to 23 feet of rain each year. The downpours feed a lush carpet of trees, shrubs, and vines that can easily obscure structures built by ancient Sāmoans, including terraces, walls, and ceremonial structures called star mounds that are unique to the islands.
“The vegetation can make it very difficult to recognize some features, even if you are right on top of them,” said archaeologist Ethan Cochrane of the University of Auckland.
Over the past decade, however, aerial mapping with LiDAR technology has enabled researchers to digitally strip away Sāmoa’s thick overgrowth. And archaeologists have been stunned by what the images show. “Almost every place you look is just littered with archaeological features,” said archaeologist Gregory Jackmond of the National University of Sāmoa (N.U.S.). “We’re finding things that, not that long ago, nobody really thought possible.”
The discoveries include vast networks of terraces and drainage ditches, as well as earthen and stone mounds in an array of sizes and shapes — including scores of previously undocumented star mounds, enigmatic structures that might have hosted ancient pigeon-catching contests. The mounds are so named because they have three to more than a dozen projections that, from above, make them look like stars.