But thanks to an expedition by archaeologists in British Columbia, the fossil record has gotten a little bigger in the last few years.
A few tiny bones offer new insight into the mini mammals that once roamed Canada's dense rainforest. Paleontologists unearthed bones from a thumb-sized hedgehog, likely the world's smallest, as well as the jaw of a tapir, a hog-like mammal roughly the size of a spaniel.
"These new mammals fill out our picture of this environment," said David Greenwood, one of the authors of the new study detailing the recent fossil discovery. The study was published this week in the Journal of Vertebrate Paleontology.
"This is part of our story. For this time period, the Eocene, we know very, very little about mammals across Canada," added Greenwood, a paleontologist at Brandon University in Manitoba.
The two fossils were found at what used to be the bottom of a lake, which suggests they were dropped there by predators. The hedgehog likely spent his final moments of consciousness clasped in the talons of an owl.
While the mini hedgehog has been confirmed as an entirely new species -- donned with the scientific name Silvacola acares, which means "tiny forest dweller" -- the tapir's remains were less conclusive as to whether the specimen warrants separate categorization.
Either way, paleontologists are excited about the bounty that remains to be unearthed in Driftwood Canyon Provincial Park.
"I think there's a lot more in this neck of the woods that just hasn't been looked at yet," explained lead author Jaelyn Eberle, curator of fossil vertebrates the the University of Colorado Museum of Natural History.