At the height of the last Ice Age, mammoths and mastodons roamed with giant bears and saber-toothed tigers, imposing their will on the era.
But it was what was scurrying around their feet that has one Schenectady scientist’s interest — and it may hold the key to uncovering the potential effects of climate change today.
Robert S. Feranec, the New York State Museum curator of vertebrate paleontology, has helped study 20,000-year-old squirrel fossils, comparing them to current California ground squirrels.
The researchers found that it’s not just temperature variations that have marked effects on animals; rainfall can have an even greater impact.
“Why that’s interesting for us today,” Feranec said, “is global warming.”
“With global temperatures rising all over, certain places will get more water and certain places will get less water,” he said. “That will affect animals more than temperature rising.”
The findings, he said, could provide a glimpse into how climate change will affect animals.
The study is published in this month’s issue of the Journal of Biogeography. Feranec co-authored the study with two researchers from Stanford University, main author Jessica Blois, a doctoral candidate, and associate professor Elizabeth Hadley. Feranec did his graduate studies at the school.
They chose the California ground squirrel because it has a wide range, throughout California and into Oregon. Fossils are also plentiful. The California variety, as opposed to our local Eastern grays, largely don’t climb trees.
The researchers used today’s squirrels and compared them to their ancestors. They found that generally their ancestors were bigger, but only by about 10 percent. (And no, they didn’t have saber-teeth.)
They were larger, the researchers believe, because it was wetter and food was plentiful. They reached that conclusion by examining the squirrels in different habitats today.
The researchers had anticipated a temperature connection — the colder the climate, the more body heat was needed.
But what they found was that precipitation had a much more direct effect on size — precipitation leads to more food and more nuts and the lack of it leads to hard times.
“It’s a much more complex picture than just temperature,” Feranec said.
They used the fossilized squirrel jaw bones to estimate their size, using constants gained from living animals. So size isn’t necessarily weight, rather their actual size.
But it was precipitation, more than the other factors, that affected squirrel size.
“We think bigger things give more information,” Feranec said. “But one of the things with small animals, is you get a lot of specimens. You can tell a lot more with more specimens than one woolly mammoth.”