Why do dog breeds look so different (compared to cats)

The reason why dog breeds look so different, and there is less difference between cat breeds is mainly because:

• The breeding of dogs has been taking place for far longer than for cats. This is because the domestication of dogs took place at least 20,000 and possibly 30,000 years ago. The domestication of the cat began about 9,500 years ago. The difference in the starting points for domestication of dogs and cats resulted in selective breeding of dogs taking place over a much longer period than for cats.
• In addition as dogs were (and still are) used more as working animals there was a greater need to selectively breed them so that they were best suited to certain tasks.

“Our data shows that very deliberate cross breeding and selection for particular traits played the biggest role in the amazing diversity running around the dog park today,” (Elaine Ostrander – chief investigator in the Cancer Genetics and Comparative Genomics Branch of the National Human Genome Research Institute, at the National Institutes Of Health).

Whereas domestic cats have been primarily selectively bred for appearance, dogs have been selectively bred for both appearance and for their ability to do certain types of work.

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For me, the bottom line is that dogs have been selectively breed for much longer than for cats and the objectives of the breeding, by its nature, resulted in greated diversity in appearance.

But Sarah Hartwell, an expert on genetics adds the following:

“..Dogs have more genetic plasticity which allows them to be bred into more diverse forms. Cats don’t have such genetic plasticity and even with selective breeding they don’t deviate far from their natural size and conformation. This may be linked to lifestyle – cats are optimised for a solitary hunter role and being full of mutations would compromise that. Dogs operate as packs and this can accommodate animals that are better, or worse at various roles in the pack such as chasing, guarding, baby-sitting, herding, killing etc. Humans worked with genetic traits already present in wolves. Wolves were predisposed to being selectively bred and changed. Cats, not having a pack to fall back on, are predisposed to resist change.”