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Why Are There More Body Variations in Dogs Than Cats?

Why are there more variations in dog breeds than cat breeds?

Have you ever noticed that there are wide variances in the body types, sizes, and characteristics of dogs but the same isn't true of cats? For example, there's a huge difference in the size and shape of a Chihuahua and an Irish wolfhound but not a big difference in the basic size and shape of a Persian and a Bengal.

Of course, there are different cat breeds with minor differences in facial structure, hair coat, and size, but nothing on the order of canine variety. Why is that?

What Causes Differences Between Breeds?

Genetic mutations cause differences between animals within a species, and some of those mutations die out while others thrive and create long-lasting changes in the species. In the case of dogs, humans interfered with evolution, breeding together dogs with mutations they liked to create many different breeds. The same thing happened with cats, but not to nearly the same extent as it did with dogs.

Dogs and Cats Have Different Jobs They Do for Humans

Dogs and cats have both lived with humans for thousands of years, and that's why we have been involved in breeding them to develop certain characteristics that could help us.

So why the big difference in dog breeds and smaller difference in cat breeds?

Dogs have performed many jobs for humans around the world in different areas and occupations. They can pull sleds, guard things and people, hunt or help hunt a variety of animals, and carry items around. When humans needed dogs to do a certain job, they bred them to accentuate the characteristics that helped them do it.

Cats, however, are more limited on the jobs they've done for humans. They have been companions and rodent hunters, keeping pests out of food supplies. For both of those jobs, their body size and shape is already perfect, so the changes humans have made through breeding cats have been mainly cosmetic.

The Dangers of Selective Breeding

The process of choosing a trait or traits to specifically breed for, to make them more pronounced in a dog or cat breed, does come with some dangers. Certain genes that help produce specific characteristics also include harmful mutations.

For instance, the gene that produces the adorable folded ears in Scottish fold cats may also affect their cartilage, resulting in a debilitating and painful condition called osteochondrodystrophy. Learn more here: "Scottish Fold Cats: An Interview with Fancy Cat."

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