I read the dogs have evolved to be omnivores, with enzymes able to digest plant foods. For example, our dog likes cornbread. This separates dogs from wolves. On the other hand, I’ve read that cats did not evolve in this way, and cats are largely restricted to a meat-based diet.Is this true?
ChatGPT said:
Yes — that’s essentially correct, and it’s one of the clearest examples of dietary divergence through domestication.
Dogs:
Over the roughly 15,000–30,000 years since domestication, dogs evolved several genetic and physiological traits that make them omnivores. In particular, dogs have multiple copies of the AMY2B gene, which encodes pancreatic amylase, the enzyme that breaks down starch into sugars. Wolves, by contrast, have far fewer copies and thus much less capacity to digest plant carbohydrates. This adaptation probably arose because early dogs scavenged around human settlements, eating scraps that included cooked grains, roots, and vegetables.
As a result, dogs can digest and metabolize many carbohydrates (like cornbread, as you’ve seen), fruits, and some vegetables without issue. They still need high-quality protein, but they are not obligate carnivores.
Cats:
Cats, including domestic cats (Felis catus), remain obligate carnivores. Their ancestors—African wildcats—were solitary desert hunters that ate prey almost exclusively. Unlike dogs, cats never co-evolved with humans around starchy foods, and they lack key enzymes and metabolic pathways for processing carbohydrates. For example:
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They have very low amylase activity.
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They can’t synthesize certain essential nutrients (like taurine, arachidonic acid, vitamin A, and niacin) from plant precursors the way omnivores can.
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Their livers are constantly geared toward protein metabolism, even during fasting.
So while dogs have become opportunistic omnivores, cats remain physiologically dependent on meat — and a plant-based diet can make them ill.
In short: dogs can thrive on a balanced omnivorous diet; cats cannot.
