Ancient Native Americans living in Florida used deadly toxic fish for mysterious purposes, study finds.

Recent archaeological excavations at the Mound Key site in southwest Florida – associated with the Calusa indigenous population – have identified “unique” deposits containing “unprecedented” abundance of porcupines and remains of porcupines (hereafter collectively referred to as burrfishes).

These fish contain a toxic compound that can be fatal to humans if ingested. In a study published in Journal of Anthropological Archaeologythe researcher suggested that the remains of burrfishes at Mound Key likely represent the specialized production and use of a toxic resource for non-food purposes not previously identified in the southeastern US.

According to study author Isabelle Holland-Lulewicz of the Department of Anthropology at Pennsylvania State University, the exact purpose burrfishes served the Calusa people has yet to be determined. The latest research is helping to shed light on the lifestyle and economic activities of this ancient Native American group.

The Calusa culture, originating from the coastal regions of southwest Florida, was a complex society of fishers, hunters and gatherers believed to have emerged around 500 AD. The culture evolved from the archaic Everglades people who inhabited the area for thousands of years.

The Calusa became particularly dominant in the region at the time of contact with the Spanish in the 16th century. This culture is known for its complex social structure, mound construction, and sophisticated use of resources found in the local environment, which included coastlines, estuaries, and small islands, allowing the group to prosper without relying on agriculture.

By the late 18th century, however, the Calusa were effectively exterminated due to a combination of factors, including diseases introduced by Europeans to which they had no immunity, as well as conflict with colonizers and other indigenous groups.

One of the most important sites associated with the Calusa is Mound Key, a 51-hectare man-made island in present-day Estero Bay in southwest Florida.

Mound Key Island, Florida was developed over many centuries by the Calusa and their ancestors through the systematic deposition and layering of shells, fish bones, and other debris from daily activities such as food consumption and tool making.

These mounds grew over time as the Calusa continued to settle and use the area, effectively raising the land above the surrounding waters of Estero Bay.

This man-made island – occupied from 500 AD through Spanish contact until the 17th century – eventually became the political and ceremonial center of the Calusa kingdom at the beginning of the colonial era.

It is characterized by a complex arrangement of waste mounds, canals, levees, burial mounds, and water courtyards—structures believed to have been used by the Calusa to capture and store live marine animals such as fish until they were needed for consumption.

Archaeological research at Mound Key has identified several deposits rich in burrfishes that date to roughly between 1000 and 1600 AD. These fish are common in both marine and brackish waters of the Gulf of Mexico.

Their notable features include a parrot-like beak and they can inflate their bodies by swallowing mouthfuls of water as a defense mechanism against predators. They also feature another defense mechanism: sharp spines radiating from the skin when the fish is inflated.

In general, burrfishes are not considered valuable or desirable food sources – at least in the Western world. First of all, these fish consist of very little meat other than the guts. Second, they—along with other relatives in the order Tetraodontiformes—contain a compound known as tetrodotoxin, which has the potential to kill a human within an hour of consumption.

The toxin affects both the central and peripheral nervous systems and can cause numbness, increasing stages of paralysis, gastrointestinal distress and respiratory failure. It can be found in the gonads, skin, liver and/or intestines of Tetraodontiformes fish.

Burrfishes are commonly found in archaeological assemblages from a variety of contexts in the southeastern United States, Latin America, and the Caribbean. However, the numbers of burrfish found tend to be low. The Mound Key site in southwest Florida appears to be an exception, with an “unprecedented” number of individuals in highly localized sites.

Interestingly, among all the remains of burrfishes found at Mound Key, no spines were identified, with beaks representing the animals. This pattern is the opposite of most deposits containing burrfishes found elsewhere in the US, Latin America, and the Caribbean, where burrs make up the majority of the remains.

Given the physiological characteristics of burrfish, including the presence of the potentially lethal tetrodotoxin, as well as archaeological evidence from the Mound Key site, Holland-Lulewicz suggests that the Calusa engaged in an economy focused on the production of some kind of non-food product. which was probably made from the spines, hides and/or guts of these creatures.

“While the global ethnographic record contains references to the conspicuous use of burrfishes, such as Melanesian war helmets, such highly visible uses would likely have been included in Spanish accounts of the Calusa, but none have yet been identified,” Holland-Lulewicz wrote in the study.

“Others have suggested the use of barbs for bloodletting, although they may also have been used in tattoo kits, as arrowheads or spearheads, or for many other uses. Calusa may have used the properties of tetrodotoxin in healing rituals.” or even military contexts, but again evidence for such use has not been identified.”

Link

Holland-Lulewicz, I. (2024). Beyond subsistence: Toxic burrfish and non-food-based economies among the Calusa complex fisher-hunter-gatherers of the American Southeast. Journal of Anthropological Archaeology, 77101653. https://doi.org/10.1016/j.jaa.2024.101653