Researchers are also trying to answer other questions at Yellowstone Lake. They are:
N How long have Yellowstone cutthroat trout inhabited Yellowstone Lake? That’s a question archaeologist Doug MacDonald hopes will one day be answered.
“It’s a simple question, but a complicated answer,” he said.
The prevailing theory is that Yellowstone cutthroat trout, which are found across the Snake River Basin from Wyoming into Idaho, migrated up the Snake to Pacific Creek and down into Atlantic Creek at Two Ocean Plateau along the Continental Divide.
“Prior to Euro-American manipulation, Yellowstone Lake cutthroat trout existed for approximately 10,000 years (since glacial recession) in sympatry with only one other fish species, the longnose dace,” researchers write in a 2006 paper.
That paper refers to a 1979 research paper on native trout written by Robert Behnke who writes that the fish likely invaded Yellowstone about 8,000 years ago as glaciers receded during high water events.
No matter when they came, it’s known they were isolated long enough - at least a few thousand years - to develop some genetic uniqueness, MacDonald said. But how much earlier were the fish established in Yellowstone Lake?
“Maybe the fish hasn’t been there as long as we think,” he said.
To find a more definitive answer, MacDonald wants to look at the geology of the two creeks along the Continental Divide to determine when they were entrenched and formed. Maybe then, archaeologists will have a better idea.
N Yellowstone Lake has several islands, and lots of cold water in between them and the shoreline. Yet stone artifacts and campsites have been found on the islands prompting the question: How did ancient people reach them?
University of Montana archaeologist Doug MacDonald theorizes that the islands were reached by earlier hunters who walked across the ice in springtime searching for grizzly and black bears just coming out of hibernation.
MacDonald backs up his theory with the ethnological findings that one of the safest times to hunt bears was just after they came out of hibernation. Killing a bear, which were feared and honored for their wisdom and strength, was a demonstration of fearlessness.
“I think it was young gentlemen looking for bears and they had a really good idea where the bears were,” MacDonald said. “They probably had snowshoes to get around.”
He also noted that Yellowstone bear biologist Kerry Gunther has seen bears on three islands as well as a hibernation den on one of the islands.
“So I really think that’s a lot of what was driving access to the islands,” MacDonald said.
Earlier theories that the early visitors used boats to visit the islands has remained unproven since no boat remains or boat making tools have been found, with the exception of one adze.
“That does not a boat making industry create,” MacDonald said.
N As the Sour Creek Dome slowly rises on the north end of the geologically active Yellowstone Lake, water in the huge tarn shifts south and erodes the shoreline. The result is the uncovering of, and sometimes washing away of, important archaeological sites.
That’s why Yellowstone National Park officials have partnered with the University of Montana to locate and excavate as many sites along the lake’s shoreline as possible. A recent cataloging of sites showed 285 around the edges of the lake.
Another reason for locating and excavating sites is to accommodate future development near the popular tourist draw, said Elaine Hale, park archaeologist. Important sites can then be protected.