I was very pleased to see the short, illustrated slice-of-life piece about a dog-vs.-beaver encounter on the Rappahannock River (“When Beavers Attack,” 9/20). You don’t have to drive all the way out to exurban Virginia to witness canine fangs pitted against rodent buck teeth in a survival-of-the-fittest contest, however. On the banks of the Potomac and the C&O Canal right here in Washington, D.C., you can see the same live show whenever you want.

For years, my morning jogs on the tow path with my shepherd cross (as opposed to cross shepherd), Sheena, were interrupted by her leaping into the murky waters to confront musky beavers. Sheena weighed in at about 90 pounds, and the beavers looked to be about half that. On dry land, Sheena certainly would have prevailed, but in the aquatic realm the outcome was never in doubt. She’d swim after the beaver, who’d slap tail to water, sound, and then resurface about 15 yards away. That exercise (far more strenuous than jogging with a human) would repeat itself until, invariably, Sheena would become so exhausted that she’d let me splash into the water, grab her, and drag her ashore. She’d never give up the chase completely voluntarily.

Once I saw three beavers engage in this game with her at once. The beavers are probably still discussing that particular sport in their lodge down by Chain Bridge. Of course, I had visions of Sheena’s big, beautiful paws being munched by the submarine beavers, but luckily she remained unscathed for 13 years.

Yeah, it was a nuisance—but I never held it against Sheena or the beavers. They were all just doing their jobs (even if it made me late for mine), and fortunately for them—and for us—they can reprise those ancient roles practically in the middle of a major city like Washington.

God bless the National Park Service.

Bethesda, Md.