New research shows that over thousands of years of dog domestication, people found sad-eyed puppies more attractive.
This, in turn, contributed to the development of the facial muscle in dogs, which is responsible for such a “facial” expression.
How pugs have changed
Pugs originally had long legs, longer noses, straight tails, and slender builds.
However, over time, they were bred to have shorter legs, flatter noses, curly tails, and stocky builds.
How have the rates changed
You've probably seen a dachshund - this is a dog that looks like a sausage with legs and looks very cute.
But initially this breed was bred to hunt animals - its elongated shape helped it penetrate into burrows.
But 100 years ago it looked much more proportional: the dachshund was 1.5 times shorter and much taller.
What did the bull terrier originally look like
The mestizos of the first generations had a very peculiar appearance: crooked legs, arched back.
Later, with repeated crossings of bull-and-terriers with terriers, the features of the latter became more noticeable: the legs lengthened, the head elongated, and the muzzle became sharper.
There were a wide variety of colors, including white.
