It was funny to read this headline, since the story broke about a year and a half ago, but I like where they went with this article which pushed the issue further than before. It’s from TVN which apparently stands for True Viral News.
Beaver dams can last centuries, 1868 map shows
Beavers aren’t just busy – they’re swamped. But while building and maintaining a marsh can take time, it’s apparently worth the investment. The rodents’ ecosystem-shaping homes have long been known for their durability, and a recent study offers unique evidence that individual beaver dams can persist for centuries.
That evidence comes via an 1868 map (see below) commissioned by Lewis H. Morgan, a prominent American anthropologist who also worked as a railroad director. While overseeing a rail project through Michigan’s Upper Peninsula in the 1860s, Morgan came across something that amazed him: “a beaver district, more remarkable, perhaps, than any other of equal extent to be found in any part of North America.”
Morgan went on to study these beavers for years, resulting in his 396-page tome ” The American Beaver and His Works.” Published in 1868, it included a map of 64 beaver dams and ponds spread across roughly 125 square kilometers (48 square miles) near the city of Ishpeming, Michigan. And now, almost 150 years later, a fresh look at Morgan’s map has revealed that most of the beaver dams are still there.
“We haven’t known much about the long-term resilience of beaver populations, but this map allowed us to look back in time in a pretty unique way,” study author and South Dakota State ecologist Carol Johnston tells Science Magazine’s David Malakoff.
“This remarkable consistency in beaver pond placement over the last 150 years is evidence of the beaver’s resilience,” she writes in the journal Wetlands.
This is fun to read again, but I was ESPECIALLY shocked by what came next.
Other research has hinted at even longer resilience. A 2012 study, for example, found that some beaver dams in California date back more than 1,000 years. One of those dams was first built around 580 AD, making it older than China’s Tang Dynasty or the earliest-known English poetry. Later evidence shows the same dam was in use around 1730, when beavers apparently made repairs to it. It was finally abandoned after suffering a breach in 1850 – some 1,200 years after its initial construction.
HEY THAT’S US! Or rather the paper that Rick and Chuck published separately in order for our mutual review to follow. I didn’t think the science article mentioned us before, so I don’t know where they got this reference. But nicely done!
Still, it’s encouraging that so many beaver homes survived the 19th and 20th centuries, a particularly turbulent time for wildlife across North America. Any averted extinction is good news, but beavers are keystone species whose DIY wetlands boost all kinds of biodiversity, so their comeback is especially welcome.
Beavers only live for 10 to 20 years, and since they’re often parents by age 3, dozens of generations could have inhabited Morgan’s ponds since he mapped them. The aforementioned California dam could have even spanned 400 generations, about the number humans have had since our ancestors began farming. Yet despite all our species’ success, we have a knack for destroying ecosystems in the process. Beavers, on the other hand, use local resources to enrich themselves and their habitats.
That doesn’t mean beavers have all the answers. But the industrious rodents are a useful reminder that we’re all defined by what we leave for our descendants, whether it’s an unpolluted atmosphere, a biodiverse bog or just a dammed place to live.
I feel like I read most of this article three or four times already. But I really love where this article ends and how it lays down the values of beaver resilience. It wasn’t an accident that they were the first animals back after Mt. St Helens errupted or after the nuclear meltdown at Chernobyl. I only disagree with one part, of course.
