Favoritos de poultrypalace

This rat was found dead under my lawn mower stored in a lean-to near my barn. It was likely poisoned as there are rodent bait stations in the area. I must explain the many photos. I have a couple previous photos of rats from our place that were identical to this animal, but on the basis of size and pelage alone, I was not confident in the identification. With this individual, I obtained the skull and boiled and cleaned it enough to see pertinent features. The combination of scaly, scantly haired tail with the cusps of upper molars in three rows solidly puts the rat in Muridae, the old-world rats and mice. Even with Verts and Carraway's key in Land Mammals of Oregon, I was having trouble differentiating Rattus rattus and R. norvegicus. The tail was definitely longer than the head and body, but I was uncertain about the skull characteristics. However, I found a key to Muroid rodents online from the University of Texas at El Paso (http://museum2.utep.edu/mammalogy/key/keymuroid.htm), which was the best I have found. With this key I was more certain that this rat was R. rattus; it explained the shape of the temporal ridges much better. Even so, I leave a small possibility that there could be some hybridization of R. rattus with other species here, for two reasons: (1) the shape of the parietals on this animal are notably longer than wide, like the R. norvegicus in Verts and Carraway (thought the temporal ridges clearly are not parallel adjacent to the parietals), and not like the more equal dimensions illustrated for R. rattus; (2) This rat is really cute and attractive (haha), with beautiful reddish brown fur over the top with some black tips mixed in, and with beautiful white undersides, and white feed with gray tops on the feet (like Neotoma fuscipes)! This is not at all like a grizzly black rat I usually picture when I think of a black rat. Perhaps there is more to be learned about rats in this area.