“And God said, Let the earth bring forth the living creature after his kind, cattle, and creeping thing, and beast of the earth after his kind: and it was so.”
I once visited the home of two colleagues who were vegetarians. I was surprised to find that they kept cats. “Can you give them a vegetarian diet?” I asked the husband, naïvely. He shook his head. “We have the choice not to eat meat,” he explained. “Cats do not – they are obligate carnivores.”
An obligate carnivore is one whose diet absolutely requires nutrients that can only be found in meat. Dogs, in contrast, are omnivores. When hiking, I have often come across the scat of local coyotes where traces of berries are clearly visible. But members of the cat family – felids – are almost perfectly carnivorous, probably only usually getting plant material by ingesting the stomach contents of their prey. Unlike less strict carnivores, like dogs and bears, cats cannot synthesize their own taurine.
As creationists, we believe that felids could have adapted by speciation, but not evolved from creatures outside their baramin, or created kind. Additionally, we see that God created all animals originally to eat plants. Presumably, cats before the Fall were able to survive on a herbivorous diet, which is impossible for them today.
After the Fall, which affected all life, genetic mutations would have occurred, and it is possible that a degenerative mutation caused cats to be unable to make their own taurine. Or perhaps their preferred plant food used to contain taurine, but mutated to stop doing so. The fact remains that cats must have changed, and further research on the reason why will always be interesting.