lol @ epic.No they don't and since you've entered the Making-Shit-Up phase of this discussion we are finished here.
H2O, seriously, you think that a Greyhound, born to run, only runs "about as good" as other dogs? Or a Whippet?
You think a Chihuahua can hunt me up some grub like a Bloodhound who, bred for incredible smelling even for dogs, has a sense of smell that is incredibly more sensitive than the Chihuahua or any sight hound out there?
That your Dachshund can just as easily take down an attacker as the German Sheppard, or "about as good"? Give it a rest. Dogs, horses, etc have been bred for ages to do specific tasks.