"This was my dog all through my childhood, Hawkins. His mother was a purebred English Springer Spaniel (liver and white) and his dad was a stray Rottweiler, who looked purebred to my aunt who saw him. Hawkins was about 65 pounds, had medium thick hair, and a spotted tongue! Hawk was *insanely* loyal to his family, our animals, and our property and was probably the best guard dog one could hope for. He was fairly submissive, but sometimes he ignored orders outright because he knew he was right, but only then. He was very dog aggressive, even though he was raised with other dogs. He was so good with our animals he would wait right by the hens as they laid their eggs, with his nose touching their feathers, and just wait patiently until she laid her egg and got up, then he would eat the egg once she left. It was so cute. He'd even let chickens walk on him when he was laying around. Sadly when he was 13 (pictured, the day before I had to put him down) he got a very fast paced lung cancer."
The Springer Rottie is not a purebred dog. It is a cross between the English Springer Spaniel and the Rottweiler. The best way to determine the temperament of a mixed breed is to look up all breeds in the cross and know you can get any combination of any of the characteristics found in either breed. Not all of these designer hybrid dogs being bred are 50% purebred to 50% purebred. It is very common for breeders to breed multi-generation crosses.