Snake River Fossil Site May 2019 Expedition

1.    What do bison have to do with The Mammoth Site?

The Mammoth Site albeit focuses on mammoths, yet the research conducted here really is about ‘everything Ice Age’.  Our research will concentrate on predominantly the Black Hills and that undefined fringed around it (WY, SD plains, NE), we do have other Ice Age projects in caves within the Grand Canyon and in the central Great Basin (Nevada).  So – our study of the Bison and then how we teach about their evolution and exhibit them in our museum area is right in line with our mission.  Interestingly, there are no bison fossils in The Mammoth Site sinkhole deposit.  The reason seems to be that the sinkhole sediments which are dating about 140,000 back to greater than 190,000 years old are before bison were here, or at least common, in North America south of the Canadian ice caps during the glacial period.  As ice began to melt, causeways opened up from Beringia (that region from the Yukon, Alaska, to Siberia) allowing bison to disperse south into what we know as the USA and into Mexico.

2.    All in all, how did it go?

Our excavation from May 4-10 was terrific.  We were able to locate what appears to be a large bone bed of bison skeletons which the Snake River let us see it by carving a path through the center.  We are not sure just how great an expanse it covers but we know it has some very large bison in it (some researchers would say that these are Bison antiquus, the extinct Ice Age bison) and some are smaller, about the size of our existing bison (Bison bison). The bison of today are actually the smallest bison that have ever existed.  The bison bone bed  is about 12 in. (20 cm.) below current river level so excavators are always deep in black bog mud!  We know that we will go back to the Snake River Farm in 2020 to open up a larger area of the bone bed to better understand it. Questions that I have include: how many bison are there?; how many years ago did this bone bed happen?; why was the bone bed created – what caused it?; what time of year/season did it happen?

3.    What did you find and what would you say is the most remarkable find?

We found LOTS of bison bones. Some were disarticulated and some were articulated (in life position and connected). We have many individual ages of bison – i.e., it was a herd of some sort and some size.  The most remarkable find I think is that we have so many LARGE bison.  One skull is of a probably 12-14 year old….big and heavy. At first I thought it was a bull but the horn cores indicate it is a female.  I feel pretty confident we have at least some Bison antiquus.  We also found some turtle and MANY lengths of wood with many chewed on by a beaver!

4.    What happens next to all these bones?

So  the skeletal remains that we removed will now be cleaned up – to get all the bog mud removed.  They will be dried out and repaired if they need it. Then we begin the long process of determining what skeletal elements we recovered, do some measurements, and then surely get a radiocarbon date both on the beaver-chewed wood and the bison bone.

5.    When is the next dig and what do you hope to find?

Our next excavation is tentatively planned for early May 2020.  We want to avoid the mosquitoes but the price to pay for this is be ready for lots of rain and some snow (as we had this year!).  I want  to find out how big a bone bed we have and answer the questions that I presented above.  In any case, it will be extremely interesting and fun!!

Bison Skull & Vertebrae
Bison Skull & Vertebrae

Bison Skull & Vertebrae at the Snake River Fossil Site.