I've been spending a lot of time thinking about rats. Thankfully, it is not because I have a problem in my apartment! Unfortunately, for many people in L.A., rats are a serious pest, and it's not just one type of rat. The most serious rodent offenders in our cities are the brown (aka Norway) rat, Rattus norvegicus, and the black rat, Rattus rattus.
Here on the North Campus we have camera trap images and footage of rats hanging out underneath the bridge. But what type of rat is this? Since Jim Dines, our Mammalogy Collections Manager, wasn't available, I decided to try and figure it out myself. Doing a Wikipedia search for brown rats, I came across a nice diagram that helped me to make an identification. What species do you think it is?