The nature / greenway near my house is also the major electricity corridor with high tension lines where the utilities company frequently cuts the taller trees.
This was a chunk cut out by one of those workers and left lying where the recent flood would pick it up and expose it.
Although I'd never seen a beaver in this area, I had seen this cottonwood tree standing a couple of years ago with not this much cutting done on it.
The beaver's teeth tracks capture my attention, along with his excellent tree felling skills (done in the past on other smaller trees).
I have cut many trees with hard steel chain on a noisy, heavy, smelly gasoline engine.
But this guy just calmly waddles up to a tree and casually sharpens his teeth, just for something to do. Doesn't even cut the tree clear down if he doesn't feel like it!

Just posting this as a bit of infrequently seen nature...
Angky.