I had one time when I trapped a new marshy area early in the fall season and there were a lot of rats and there were a lot of the older, bigger rats with scars and bite marks from the spring before. None of the younger rats were bitten up. There turn would come the next spring. We have a lot of small ditches that run intermittenly depending up on rain and rats move up and down those all year if there is water and especially after big rains. We have not had near the rain and many of these ditches and small sloughs are dry for a couple years. Wondering rats are not moving into new territories in our area and less fighting etc. from my experience.
Bryce
Keep in mind that there can be several mates over the “growing “ season. I believe that heavy rain events stimulates the muskrats instincts for reproduction and dispersal . It is natures way to recognize and fill habitats capacity. So to the contrary lack of rain (water) hinders reproduction. Just a theory.
I guess what I’m getting at is your bit fall rats could have been participating in a fall mate. Which sometimes happens as occasionally we capture “mice” under ice, which can’t be more than a month old, based on their small size. Otherwise bites heal quite quickly and late spring molting changes the leather of our little buddies.