Canada beaver (Castor canadaensis) is similar to the European Beaver and are the second largest rodents on the planet. A family will occupy a large valley constructing a dam and breeding in a subaquatic chamber. Young beavers that fail to nest usually succumb to roadkill or trappers, which is quite legal in Canada and USA. Populations are stable. The third image is a size comparison to the South American beaver rat (round tailed beaver) called Coypu, also available on this site.