Why did big cats need to evolve into smaller house cats?

They didn't. You see, like canids, which can be separated into larger dogs like the wolf, African wild dog, coyote, jackal, and similar or smaller dogs like foxes, bush dogs, raccoon dogs, and the like, cats are the same. read more

Modern cats, both large and small, all evolve from a rather big cat, Pseudaelurus, which was up to 5 feet long and 50 pounds, and existed 8 to 20 million years ago. However, many believe an earlier, smaller animal, Proailurus (first cat), weighing in at about 20 pounds, is the first true cat, which lived about 30 million years ago. read more

All Cats, Large and Small All cats -- that is, all felids -- share common traits. This might seem counter-intuitive if you're comparing your house cat with a tiger. read more