Mastodon dung reveals its diet and environment in Nova Scotia about 75,000 years ago
Three decades after researchers recovered behemoth remains from a Nova Scotia gypsum quarry, discovery generates new information about the species’ habitat in the days before one of the animals fell. resembling elephants in a sinkhole and died about 75,000 years ago.
Using a small specimen of rock-like dung, scientists reconstructed the animal’s diet and environment, concluding that the juggernaut was a navigator – largely in a forest environment soaking up shrubs and branches. , but also insects, pollen and algae.
Scott Cocker, now a doctoral student at the University of Alberta, led the research and publishes the results in the Canadian Journal of Earth Sciences.
“They gave us a big picture of a time in Nova Scotia 75,000 years ago. The factories were pretty similar to what we see in Nova Scotia today, ”Cocker told CBC News.
“Lots of spruce trees, there is birch, there is alder. A mixed forest, dominated by spruce, where we still have a lot of deciduous trees like oak. And also there were wetlands, again freshwater wetlands in the region. “
Most important, he said, is what the juggernaut accidentally consumed while sailing.
Analysis revealed the first known Canadian remains of a bark beetle. Its size indicated that the mastodon was feeding in late summer or early fall.
“We pick up other types of microorganisms that all ended up in the water or on the trees they eat,” Cocker said.
“And that’s what actually gives us the perfect picture, because if we just rebuilt based on what it meant to consume, we get a very small picture of what’s really going on.”
Half a cup of dung
Cocker obtained a 50 gram piece – about half a cup – of manure, which he broke down in a weak solution of hydrochloric acid, and sifted the pieces through a series of sieves.
The specimen was released to the public by the Nova Scotia Museum of Natural History in Halifax, which houses the partial skeletal remains of two behemoths found in East Milford, Nova Scotia, in 1990-91. In addition to bones and droppings, researchers also found two turtles and a frog at the site.
Tim Fedak, the museum’s geological curator, said the dung was an ecological archive.
“What really struck me was the diversity of plant and insect life that it [Cocker] was able to reconstruct from that small sample we provided, ”Fedak said.
“You can imagine this behemoth coming down from a mountainous region into a plain and just grabbing spruce branches and nibbling on them, and it turns out there are bugs on them and cones of seeds and stuff. .
“So you get a really good overview of that particular environment at that point.”
In search of clues
Cocker said the dung specimen and other research indicate this was likely an optimal period for mastodons – providing a baseline of conditions before their extinction some 13,000 years ago after the last period. glacial.
“The only way to really understand extinctions is to look back to understand how the animals and plants of the past lived,” he said.
“What kind of environment they lived in, how they functioned ecologically. What happened? What are the factors that led to this change? Was it the climate, was it a changing environment? Was it human pressure?
What tooth enamel can reveal
The search for clues to understand extinction also motivates the research of Laura Eastham of Saint Mary’s University in Halifax.
She is performing isotopic tests on the enamel of the teeth of the jaw of one of East Milford’s behemoths.
Chemical analysis can tell when it has reached maturity, if it has been drinking fresh water from a glacial stream or lake, if it has migrated a long distance in its lifetime, and if its diet has changed.
“I’m doing this not only because it’s really interesting to understand what these fossil mammals were doing, but also because looking at how they reacted to climate change tells us a lot about how modern species might respond to climate change.” , said Eastham. .
“So this will help us limit modeling and also inform how we develop conservation strategies.”
Fedak said new techniques allowed scientists to examine specimens in new ways.
“There will be people looking at these specimens 100 years from now, I’m sure, with even more new tools and new questions,” he said.