Norway rats (Rattus norvegicus) are sometimes called brown rats or sewer rats. They have thicker bodies, shorter tails, and smaller ears than roof rats. It may be very difficult to distinguish Norway rats from other rodent species, particularly roof rats, based on appearance alone.
Their droppings have blunt ends and are approximately 3/4″ in length.
Norway rats use underground burrows and may be found on creek banks, shorelines, and sewer systems. They should be suspected if rats are seen entering burrows or tunnels in the ground.