Here is Cassie, Red Heeler:
In her prime, she scored 1600 on her SATs: then, to paraphrase Charles Barkley, killed every varmint
and their families.
She is still with us at 16. She is a little slower, but still has, to quote Monty Python, "a mean streak a mile wide..."
I love my Labs but the Heeler is the best in breed in my life of dogs.