Bear-Sized Giant Beavers Once Roamed North America

6 days ago (smithsonianmag.com)

Not just giant beavers, there were all kinds of giant animals before humans arrived. Great sloths, mastodons, etc. etc. New Zealand had these huge birds, Moa, there are sites where they've found piles of bones and fireplaces obviously made for eating Moa, which went extinct quite soon after humans arrived.

https://en.m.wikipedia.org/wiki/The_Sixth_Extinction:_An_Unn... is a pretty fun read about how we've destroyed everything in our path.

QUICK: Name the animal whose industry is most visible from space.

Day or night?

That was a trick question. Day.

Easy. The Beaver. If it were not for beavers evolving beside us, the Eastern US and much of the world would very nearly resemble the driest American Southwest of today, with rain being gathered after a brief overland wash into deep river gorges, with little water left behind close to surface. Past a certain age of erosion even introducing beavers would not help. Shallow masses of water diverted overland is crucial to sediment distribution and the formation of oxbow lakes. If beavers had arrived late their industry would be slowing rivers already confined by steep gorges and the violence of waters would carry them away and destroy them and their families.

When beavers are gone and what is left is the flaky erosion patterns of human desire the future landscape will be a crap shoot... for humanity could never match the attention and focus of the beaver.

  • Beavers are only endemic to North America and parts of Europe. So why does the rest of the world not overwhelmingly resemble the American southwest?

    • Good Q. Since there are many wetland plant species and willows that are beaverlike you could ask how would they become established in the first place, and how would their growing mass and persistence compare to a beaver's after a catastrophic event? And after all, why does the dry deep-gorge Southwest look like the Southwest anyway? THAT could be the outlier and its depth and dryness would seem the result of a 'jump start in erosion' bestowed over geologic time. I think even the Southwest may have been on course to be as green as the East and would have been -- had it not been for some truly horrific floods that eclipse anything in the modern era when the plugs for Glacial Lake Missoula and Bonneville gave way.

      Drainage paths in the West ( https://i.dailymail.co.uk/i/pix/2016/10/21/16/3995911F000005... ) were more narrow and violent, the same in the East were not. A minimum of sudden deep erosion and therefore sideways diversion of blocked watercourses would be necessary for beavers to get established and shape the landscape so in the East they did. Other places in the world like the Amazon may have been shaped by vegetation impeding erosion more so than gnawing creatures.

  • > If it were not for beavers evolving beside us, the Eastern US and much of the world would very nearly resemble the driest American Southwest of today, with rain being gathered after a brief overland wash into deep river gorges, with little water left behind close to surface.

    The rainfall patterns are very different in those two areas. I don't doubt that beavers have important erosion and sediment retention impacts that over time do have a massive impact on the ecosystem and landscape. However, sediment rention is far from only reason why the american SW looks so different from other parts of the country.

  • > the Eastern US

    The eastern US pretty much wiped out beavers as most landowners view beavers as pests. Does not look anything like the southwest. If we introduce beavers to nevada, do you think nevada will look like upstate ny?

    > much of the world would very nearly resemble the driest American Southwest of today

    Most of the world doesn't have any beavers. Most of the world does not resemble the american southwest.

    Rather than beavers creating the environment, it's the environment that created the beavers. Beavers exist in areas with plentiful rain/water for a reason. Look up rainfall patterns in the US and you'll see how illogical your argument is.

  • The only evidence of any animals activities visible from the Moon, is a clear cut 100miles by 150 miles in norther BC, as seen by humans on the moon..... There are two species of Beavers left, the well know aquatec version and a "woods beaver", rare. Beavers are making a comeback, and I see dams and lodges regularly, and hit a very large one driving, which I put in the back of the truck and took to a friend and we scun it, and he stretched the hide old style, easy to see why the fur was in such high demand, it's glorious, nothing synthetic can match the feel.The tails are a culenary delicacy. Not long ago Beavers and other species were still faceing an onslaught of human depredation, as there was a larger ,more vigerous rural human population, and guns and dynamite were hardware store items. Hyway departments still remove beaver dams where flooding threatens roads, but as flooding is becoming more damaging overall, the response is often to build MUCH larger drainage and bridge structures and then be able to let nature do it's thing.

  • By that logic, I'd vote for worms. Forestation is only possible after worms create enough humus to support trees.

I wonder if they were tasty. You never hear of people eating beaver.

“So, the first inhabitants in this land would have been encountering the giant beaver.”

...and killing them.

It's curious how megafauna extinctions coincide with human arrival... Native Americans, Australian Aborigines, and other "First Peoples" were just as deadly as later European settlers.

The Once and Future World by J.B. MacKinnon eloquently describes our disastrous impact on Nature: https://www.jbmackinnon.ca/the-once-and-future-world

  • > It's curious how megafauna extinctions coincide with human arrival... Native Americans, Australian Aborigines, and other "First Peoples" were just as deadly as later European settlers.

    That's one possible, maybe even likely scenario.

    But humans started moving around at that time for a non-human reason; the end of the Ice Age. There's some evidence for populations of large mammals dying out before humans are believed to have showed up in those places, like Australia.

    (As with most changes of this magnitude, the true answer is probably "more than one thing".)

    • Also, we tend to think of human effects and the change in climate to be mutually exclusive, but even if the end of the ice age had zero effect on the ability of megafauna to eat or reproduce, and an increase predation from the introduction of humans was the sole cause of their extinction, the presence of those humans itself would be an effect of the ice age ending.

    • These animals survived multiple climate changes before that. Nope, it was humans.

      We're the reason the North American continent has _no_ large predators except bears.

      3 replies →

  • > It's curious how megafauna extinctions coincide with human arrival... Native Americans, Australian Aborigines

    Native americans and australian aborigines arrival coincided with drastic climate change. Or put another way, climate change was a major driver of human migration.

    > were just as deadly as later European settlers.

    Unless natives and aborigines had guns, railroads, mass farming, etc, I highly doubt it. Not to mention the population boom due to modern medicine and mass migration.

    If you consider the relatively small native american and aborigine populations, the technology involved and how gigantic america and australia is, it's absurd to think natives or aborigines wiped out the megafauna.

    Species extinction has two major causes - climate/environment change and loss of habitat. Were the natives and aborigines sophisticated enough to cause climate/environment change or develop farming to a degree that deprived the megafauna of their habitats? I highly doubt it.

    • > it's absurd to think natives or aborigines wiped out the megafauna.

      Aside from the plausible scenario of driving whole herds off cliffs (because it was safer than trying to separate one or two from the herd).

They say it "could have weighed up to 200 pounds". How do they know? Are they just guestimating based on modern animals about the same size? Or maybe weighing/measuring a modern beaver and scaling up size and weight?

I wonder how similar their diet was to modern beavers, especially if they also ate bark and cambium?

  • https://en.wikipedia.org/wiki/Castoroides

    > Stable isotopes suggest that Castoroides probably predominantly consumed submerged aquatic plants, rather than the woody diet of living beavers. There is no evidence that giant beavers constructed dams or lodges. The shape of the incisors of Castoroides would have made it much less effective in cutting down trees than living beavers. It was likely heavily dependent on wetland environments for both food and protection from predators.

A conibear #330 isn't going to even dent that. I'd need a #3300 and farm jack to set it.

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