All of the above are real threats to earthen dams...pond owners often fail to understand then, watch for them and take corrective action. NRCS is your friend and can help with advice but pondowners first need to stay of top of things and keep their eyes open for trouble signs.
One critter most people dont think about that will destroy a pond dam is gophers they will cut their runs thru it and you get a good enough rain and it finds the runs it will start eating away at the dam to the point it will give way quickly.
i used to build dams. if it had a pipe as the primary spillway and the anti seep collars werent big enough or rusted out etc and rodents gophers etc tunnel beside the pipe it will surely do that. hint hint replace with a welded steel pipe with plate anti seep collars welded directly to the pipe. pipe and stay away from spiral wound pipe
We used to own a home with 5 acres and a pond. One had to drive across the dam to get to the house from the road. It sure would have been crappy had that happened to us. It had a large pipe as a primary spillway, but I have no idea if it had anti-seep collars or not.