Humanity stands slack-jawed before the fossils of giant animals and birds that once roamed the world, striking terror into the hearts of proto-mammals large and small. And few were as tiny as the dinky fossil hedgehog discovered in Canada, of which a whole family could have fit comfortably in the palm of your hand.
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This tiniest of all known hedgehogs was all of 2 inches long in full-fledged adulthood, and that's counting the cute little spikes it may or may not have had. Hedgehogs are known for their protective coating of quills but these fossils were too deteriorated to show whether or not Silvacola acares had any.
Primitive hedgehogs in Europe of the time had bristly hair, so Silvacola may have had it as well, says University of Colorado paleontologist Jaelyn Eberle.
Silvacola lived 52 million years ago in a rainforest in northern British Columbia, at a time that the planet was especially warm. Its scientific name means "tiny forest dweller."
To be accurate, Silvacola never saw dinosaurs, it seems. It lived roughly 13 million years after an asteroid wiped out the dinosaurs and left the mammals as the dominant land animals.
About the length of your thumb, the wee hedgehog supped on bugs, plants and maybe seeds, paleontologists surmise.
"We were surprised by its tiny size, and frankly it threw me for a while and made it difficult to identify," said Eberle, one of the researchers in the study published in the Journal of Vertebrate Paleontology.
"Today's hedgehogs, and especially the ones that are kept as pets, are considerably larger. The smallest living hedgehogs are about 4 to 6 inches long, not including the tail, Eberle said, "but the moonrats can actually be upwards of 18 inches long and weigh a few pounds."
Moonrats look like nothing so much as albino shrews, with long snouts and beady black eyes. Some have grey and black coloring as well. Despite their attractions, one doesn't want to pick on up for a cuddle because, reportedly, they reek.
And then there was a tapir
Instead of being removed from the surrounding rock, as paleontologists usually try to accomplish – Silvacola's delicate upper jaw was examined with a high-resolution CT scanner at Penn State University to avoid damaging the teeny cheek teeth.
The earliest known member of the family that includes hedgehogs and moonrats lived about 58 million years ago. Today's hedgehogs and their relatives live in Europe, Asia and Africa - and Israel, where they are commonly observed in the cities at night, often eating dried cat food left out for street cats.
The researchers described another interesting mammal called Heptodon found at the same site, Driftwood Canyon Provincial Park. It was a tapir-like creature about as big as a medium-sized dog. It was a herbivore about half the size of today's tapirs but lacking the short trunk usually seen in these mammals.
The half-pint hedgehog and trunkless tapir lived in a rainforest along the edges of a lake, but it was not tropical, the researchers said. Rather it was a cooler, upland rainforest, more akin to today's climate in Portland, Oregon in the U.S. Pacific Northwest, about 1,100 km south of this location.
"Driftwood Canyon is a window into a lost world, an evolutionary experiment where palms grew beneath spruce trees and the insects included a mixture of Canadian and Australian species, said David Greenwood of Canada's Brandon University, another of the researchers. And now that world is gone, together with the tiny trunkless tapir and the world's smallest hedgehog.