The Dirtiest Job at SEAC?

Southeast Archeological Center zooarcheologist Brian Worthington has moved his maceration operation to Goodhope Farm with the permission of Human Remains Dog handler Suzi Goodhope, of course.

buckets field and horse
The buckets in the foreground contain the decomposing remains of animals whose skeletons are bound for the SEAC zooarcheological comparative collection

SEAC archeologists were recently at Goodhope Farm excavating two horse skeletons with the help of Florida State University anthropology professor Dr. Geoffrey Thomas and his students. Meanwhile, Worthington was tending to his collection of five gallon buckets containing the putrefying remains of various critters whose skeletons will be added to SEAC’s zooarcheological comparative collection. When the buckets were open, one could smell them downwind everywhere on the property!

Buckets Screen Capture

Maceration is the rather grizzly process of removing all of the soft tissue from an animal skeleton by submerging it in water 

Before beginning the process, the animal is weighed and a variety of measurements are systematically obtained. Some measurements are derived from zoology while others are specific to zooarcheology. They were first adapted for zooarcheology by Dr. Elizabeth S. Wing, Curator Emeritus at the Florida Museum of Natural History and Professor Elizabeth J. Reitz at the University of Georgia. Other data including locality, sex, age, and collection date are also recorded for each animal.

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Next, as much of the flesh as possible is cut away from the carcass and the organs are removed. It is good practice to soak birds before defleshing to prevent a feathery mess. The skin and viscera are weighed, followed by the cleaned skeleton. The mathematical difference between these weights is an estimate of the amount of the meat provided by the animal.

fish-bag-tag
The fish were sealed in individual tagged bags

Fish, in some cases, are placed into the bucket whole to recover the scales, which can be diagnostic, along with the bones.

Summer is the best time for macerating because the high temperatures promote the growth of bacteria that break down soft tissue. The buckets are kept outside for obvious reasons, and to keep the smell down, some of the water in the bucket can be drained and fresh water added after a few days. Ideally, the temperature remains relatively constant.

chicken turtle maceration
Brian pouring a chicken turtle out of a maceration bucket

The carcass remains in the bucket of water until the great majority of the tissue has detached from the bones; this took about three weeks for the bluefish, kingfish, grouper, surgeon fish, barracuda, cod, loon, wood duck, coney, chicken turtle, channel catfish, osprey, and beaver in Worthington’s buckets.

The contents of the buckets are poured through a screen 1/16 inch or finer, or a paint strainer mesh bag. The skeleton is transferred to a solution of hydrogen peroxide and water to disinfect it, remove the smell, and dissolve any small bits of flesh that may still cling to the bones. It remains in this solution for no more than 24 hours because the hydrogen peroxide can begin to damage the bones themselves.

Peroxide 1
Hydrogen peroxide bubbles as it disinfects the macerated bones

In some instances, the macerated skeleton may also need to be de-greased by submerging it in acetone for anywhere from a week to a couple of months. Small holes drilled into the larger bones of larger mammals can facilitate leaching the marrow.

BW_lab
Note the neatly labelled containers in Brian’s personal zooarcheological comparative collection

When the defleshing and degreasing is complete, each skeleton is assigned a unique catalog number which is entered into a database. Each bone is labelled with the catalog number. The box containing the skeleton is also labelled with the catalog number as well as the genus, species, and common name of the animal. The specimens in SEAC’s collection are organized by taxonomic order.

 


Human_Skull_being_cleaning_by_Dermestid_Beetles
Dermestid beatles defleshing a human skull. Source: Wikicommons

Maceration is not the only method of preparing faunal specimens for the comparative collection. Fire ants have been used to deflesh skeletons. But, they bite the hand that feeds them, so to speak, and they have a tendency to displace small skeletal elements. Colonies of beetles of the family Dermestidae are considered to be one of the most effective agents for cleaning smaller animals.

Dermestes_maculatus_DeGeer,_1774
Dermestes maculatus. Source: Wikipedia
However, these critters are high maintenance and can pose a danger to curated organic artifacts. According to Worthington, some dermestid beetle colonies can even develop a preference for particular animals and grow picky about what they eat.

tupperware bones crop
The submerged deer was less decomposed

Besides the specimens macerated in the buckets, two deer and a sheep buried at Goodhope Farm were excavated. The deer had been placed in Tupperware containers. One container was filled with water. The other container had been filled but was disturbed by some living animal. It was resealed but never refilled with water. Unexpectedly, a considerable amount of soft tissue remained with the submerged skeleton along with a strong odor of decay while the dry skeleton was relatively clean and odorless.

Like the specimens in the maceration buckets, the contents of both containers were rinsed on 1/16 inch screens. The bones were placed in buckets to be soaked in hydrogen peroxide solution.

skull into bucket.JPG
Brian and Dr. Mike Russo rinsing deer bones before placing them in hydrogren peroxide
bone from tupperware 1
Note the adipocere in the screen with the deer bones

Even when most of the flesh had decayed, a brittle, white material resembling limestone was found with the skeletons. This substance was adipocere formed by the decay of fat.

Serenaded by Eric the sheepdog, the archeologists used shovels and trowels to excavate the grave of a sheep, donated by Meaghan Thacker, which was marked with wire. Its carcass was buried with a sheet had been used to drag it to its grave. When the sheet was spotted during excavation, the archeologists began screen the soil matrix through 1/4 inch hardware cloth. The archeologists ended up with more than they bargained for. The sheep was apparently pregnant when it died.

20160620_124122
Andrew McFeaters prepares to excavate the sheep

The skeleton of an unborn lamb was found with the sheep.

brian lamb id crop
Brian identified lamb bones among the sheep bones

All of these skeletons will be joining the SEAC zooarcheological comparative collection along with the horse skeletons excavated at Goodhope Farm.

What do you mean you haven’t you seen SEAC’s video of the horse excavation?!

ICYMI click here

  • None of the animals in SEACs collections were culled specifically to be added to the zooarcheological comparative collection.

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