Manis Mastodon (USA)

Pre-Clovis Megafauna Hunting Strategies

3-D Reconstruction of the Bone Point in Manis Mastodon Rib
3-D Reconstruction of the Bone Point in Manis Mastodon Rib. Image courtesy of Center for the Study of the First Americans, Texas A&M University

The Manis Mastodon site is a preclovis site, located on the Olympic Peninsula of Washington state in the Pacific northwestern United States. It was discovered in 1977 when a farmer unearthed two mastodon tusks from a pond in a glacial kettle, a marshy depression in the Sequim Prairie bog within a dense conifer forest.

Pollen studies at Sequim Prairie were conducted in the 1980s. These indicated that at the time of the occupation, the region was undergoing an arid period, and the site would have been within an opening dominated by shrubs and other plants that included cactus.

The region was colonized by coniferous forest between 11,000 and 9,000 years ago.

Manis Site Artifacts

Manis consists of most of the bones of a single male extinct elephant (mastodon), excavated in 1977-1979. The mastodon lay on its left side within a depression, and the left (lower) half of the mastodon was fairly intact. Its right (upper) side was missing two bones (the right femur and right fibula), the rest of the bones were disarticulated (taken apart and scattered) and the skull was fragmented. Cut marks, spiral fractures and flaking were noted, although there is no evidence that the bones were weathered or gnawed by carnivores.

No stone tools were identified at the site, but the tip of a bone point is embedded in a rib. The point was examined by high-resolution computed tomography (CT) and reported in 2011. The point fragment is 3.5 centimeters (1.4 inches) in length, and 2.15 cm (.85 in) of its length is embedded in the rib.

Scholars calculated the minimum length of the bone point as 27-32 cm (10.6-12.6 in) long, based on the amount of animal skin and muscle the point would have had to penetrate to make it into the living rib. No bone growth is in evidence around the embedded point, indicating that the mastodon died soon after it had been attacked.

The bone point itself was made from another mastodon's bones.

Dating Manis

Radiocarbon dates taken during the 1970s on the organic materials within the site averaged ~12,100 RCYBP, earlier than any Clovis occupations, which date between 11,000-10,800 RCYBP. At the time, Clovis was the earliest widely-accepted human culture believed to have occupied North America, and, because of that, and because there were no stone tools found at Manis, the site was not accepted by most scholars.

By the early decades of the 20th century, sufficient evidence of occupation within the Americas predating Clovis had been discovered, leading to additional investigations of Manis, among many other possible pre-Clovis occupations. A suite of Accelerated Mass Spectrometer (AMS) radiocarbon dates were reported in 2011, on the purified bone collagen extracted from the mastodon rib in which the bone point is embedded, and from two different mastodon tusk fragments. These new dates range between 11,890+/-35 to 11,990+/-30 RCYBP, or 13,860-13,763 cal BP, some 800-1,000 years older than Clovis.

Manis and Pre-Clovis

The location of Manis in the Pacific northwest, the identification of bone points, and the new suite of radiocarbon dates, strongly supports adding Manis to the growing number of accepted Pre-Clovis occupations in North America.

Unlike most other Pre-Clovis sites, Manis, suggest that megafaunal (large mammal) hunting was part of the subsistence strategy of these little-known diets of hunter-gatherers. Other sites which reflect such early megafaunal hunting strategies include Ayer Pond in Washington state, and Hebior and Shaefer sites in Wisconsin.


This glossary entry is a part of the guide to Pre-Clovis culture, and the Dictionary of Archaeology.

Borden CE. 1979. Peopling and Early Cultures of the Pacific Northwest: A view from British Columbia, Canada. Science 203(4384):963-971.

Petersen KL, Mehringer Jr. PJ, and Gustafson CE. 1983. Late-Glacial Vegetation and Climate at the Manis Mastodon Site, Olympic Peninsula, Washington. Quaternary Research 20:215-231.

Waters MR, Stafford Jr. TW, McDonald HG, Gustafson C, Rasmussen M, Cappellini E, Olsen JV, Szklarczyk D, Jensen LJ, Gilbert MTP et al.

2011. Pre-Clovis mastodon nunting 13,800 years ago at the Manis site, Washington. Science 334:351-352.