The castoides skull copy is one our most prized beaver exhibit items. For years we’ve been answering questions about this dinosaur beaver, reporting the slightly incredible research based on isotope analysis that they didn’t eat trees but survived on very small pond weed. People always scoff at that, and say then what are those big teeth for? Which I can never explain.
But Castorides wasn’t the only beaver.
The family of castorids used to contain many members all evolved into their own niche and constrictions. Dipoides was actually smaller than our beaver and some brand new research indicates it miraculously cut trees for food. Wait, what? A beaver the size of a bear lived on pondweed and a beaver the size of a lapdog cut down trees? Well yes. Little trees. Do not ask me why on earth the giant beaver didn’t cut trees and the small beaver did. But that’s evolution for you, Apparently they cut the trees first, because they were hungry, and then when things started freezing their cousins thought, hey maybe there’s a value in building up the water and saving some unfrozen food.
Maybe being the midsized beaver that could do it all made sense in the long run.
Ancient Arctic beavers were cutting down trees for food at least four million years ago – long before they started building dams, study shows
By studying the wood-cutting behaviour of ancient beavers that once roamed the Canadian high Arctic, an international team of scientists has discovered that tree predation – feeding on trees and harvesting wood – evolved in these now-extinct rodents long before dam-building.
This is an important discovery as woodcutting is a key behaviour for modern-day beavers’ capacity to modify, create and maintain habitats.
This new research suggests that tree predation has existed for more than 20 million years, enough time that might have allowed beavers to affect the evolution of certain trees species.
The ancient beavers, belonging to the fossil lineage Dipoides, lived four million years ago and were approximately two-thirds the size of today’s Canadian beavers. They gnawed trees with rounded front teeth, not squared teeth like their modern relatives, and researchers believe this woodcutting behaviour originated for harvesting food, not from a compulsion for building dams.
The study, published today in Scientific Reports, is first-authored by Tessa Plint, a former Western University graduate student currently pursuing a PhD at Heriot-Watt University (UK).
“Ancient animals and ecosystems that thrived in the high Arctic during warmer times in geological history show us a glimpse of what this biome could look like in the future under the effects of global warming in polar regions,” said Plint.
“Today, the beaver has a profound impact on the landscape and is known to increase the biodiversity of the local ecosystem through tree-harvesting and dam building. It’s fascinating to look back in time and figure out how this hyper-specialized toolkit of behaviours came to be.”
At Western’s Laboratory for Stable Isotope Science, researchers examined chemical signatures preserved in ancient beaver bones to figure out what exactly they were eating four million years ago –and, surprisingly to them, it included trees.
So there you have it. Sometimes it looks like you’re suited for one purpose and it turns out you do something completely different and blow them all away. And sometimes you have the perfect seeming qualities, and everyone treats you as a “RINGER” for sure, and you fizzle out and eat pond weed.
Go Figure.
