If you are anything like me, you enjoy reading non-fiction. If you are even more like me, you might find yourself hyper-fixated on non-fiction about a particular species; purple pitcher plant, pipevine swallowtail butterflies, and eels to name a few. Currently, and what I would like to share with you all, I am quite eager for beavers!

A beaver swimming through water holding something in it's paws near it's mouth.

Castor canadensis (Photo credit: https://americanprairie.org/project/beavers/)

Being within the Anthropocene, humans have the tendency to believe that our species are the ultimate organizer or orderer of the natural world. I challenge that beavers are the original and superior ecosystem engineer. From an anthropocentric perspective, beavers create chaos, disorder, mess, financial implications… (insert other negative vernacular here). That disorder and mess is really complexity. Beavers create epic, architectural works, which are really just a means for survival and procreation, but that support biodiversity and dynamism on the landscape. Don’t believe me? Do some research on trumpeter swans as well as Saint Francis’ satyr butterfly, and find out for yourself! While I could continue to wax poetic about beavers being the worthier ecosystem engineers, I want to use this platform to share some outright interesting beaver fun facts so we can reframe our thinking on this special rodent.

A snowy wetland area surrounded by trees and a mountain in the background.

A landscape modified by beaver activity in West Virginia (Photo credit: Christine Danforth)

Beaver Fun Facts*

In no particular order:

  1. Beavers…: Beavers have the incredible ability to hold their breath for around 15 minutes. They have beautiful webbed feet, making them powerful and nimble swimmers. Adding to their adeptness in the water, they have transparent eyelids (literally built in goggles)! Beavers have a second set of fur lined lips that close behind their teeth, so they can process wood (and do other aquatic organism things) without drowning. On the topic of their teeth, the rodent has two upper and two lower incisors that grow continuously. The front side of their teeth is coated in hard dense iron rich enamel, the reverse side is made of softer dentine, wearing at different rates as to be self sharpening. Beavers are generalists; one researcher found 42 tree species, 36 genera of green plants, 4 species of woody vines and an array of grass species in the intestines of a deceased beaver. These stunning rodents practice cecotrophy (eating their own feces), managing to digest about a third of the cellulose they consume (an anecdote to “work smarter, not harder”).
  2. Castor sacs: Beavers maintain internal castor sacs, which have evolved to delineate beaver territories. Beavers combine urine and castoreum, a brownish-yellow secretion from the sac, to establish dominance of space and to deter predators. Castoreum is in fact FDA approved, so can be used as natural flavoring within food; castoreum oil has an incredible vanilla or raspberry scent and flavor. Historically, castor oil was used in the production of imitation vanilla. This is purported to be a relic of the past, and that almost all imitation vanilla is now synthetically produced or created via a primary producer.
  3. Fur Hats: Because beaver fur is so soft it is argued to have spurred the colonization of a continent! Fortune seekers ransacked North America for beaver pelts; simultaneously, devastating old growth forests and decimating indigenous communities. Beaver hats were felted with mercury nitrate by hatters. Hatters that handled this neuron toxin are believed to have coined the phrase, “mad as a hatter,” due to the lasting health effects. In 1941, after environmental and human health had been sacrificed for decades did this toxin get removed from the hatting process.
  4. Evolution over 30 times!!: It has been determined that over millions of years around 30 genera of beavers have evolved and vanished. This is identifiable by the shapes of skulls of fossils, as well as the determination that the odds of the unique behavior of tree harvesting evolving more than once are extremely slim.
  5. The Beringia Land Bridge Theory: It is believed that the genus Castor, the genus for modern beavers, arose some 10 million years ago as aquatic beaver-like species traveled from North America to Eurasia via the land bridge Beringia. DNA analysis suggests some 7.5 million years ago, a number of Castor species migrated back into North America via the Beringia land bridge. Beringia was flooded by rising seas approximately 5.5 million years ago allowing for isolation and independent evolution between the Eurasian and North American beaver. It is believed that about one million years ago the modern North American beaver, Castor canadensis, evolved. With this shared history even some experienced wildlife biologists may struggle to determine between C. canadensis and C. fiber (the Eurasian beaver).
A tree trunk with some bark worn away near its base.

Beaver activity found on a buffer site in Northern Pennsylvania (Photo credit: Christine Danforth)

Optional (but highly recommended) reading:

  • Beaverland by Leila Philip
  • Eager: The Surprising, Secret Life of Beavers and Why They Matter by Ben Goldfarb

*The information above has been adapted from Ben Goldfarb’s novel

Before European arrival to North America somewhere between 15 and 250 million beaver ponds influenced the landscape. While beaver numbers have massively rebounded, their influence on the landscape is influenced by the Anthropocene. Next time you see one of these friendly rodents, or their work, stop and reflect on what you think the landscape may have looked like prior to Western settlement.