Have you ever wondered why the spring season in both hemispheres feels as old as forever and as young as a newborn baby — at the same time?

Evolution goes back billions of years, but new possibilities open up whenever life awakens and reproduces itself.

On a related note, ever wonder about how cats evolved? Or how closely related house cats — the “lions in our living room” — really are to the big cats?

Sabercats cannot be ignored. (Image: Wim Hoppenbrouwers, CC BY-NC-ND 2.0)

And what about those saber-toothed cats?

Earth’s apex predators have gone from T. Rex & Company to today’s lions, tigers, and other carnivorous mammals (including domestic cats, which are apex small predators in most human-dominated habitats).

Why did evolution take this route?

All of these animals are fascinating. Everyone loves the extinct dinosaurs and sabercats wholeheartedly. Most people love, and in some cases, fear the beautiful wild cats living around us now.

Most of us don’t go much farther than that. That’s too bad because what little scientists can understand of the 66-million-year-old history that connects these two groups of predators — ancient and modern — is amazing.

Since I’m not a scientist, how do I know this? I looked it up and now I want to tell you what I learned.

Here’s how that happened.

Her story

TLVshac, CC BY-NC 2.0

I got thinking about cats and their place in the world in 2014 after retiring from twenty-five years in medical transcription: a job that involved research of medical terms, 100% accuracy, and the opportunity to listen to experts translate complex scientific ideas into simple language for the medical record.

What better way to fill my new spare time than by writing a book about how cats evolved?

I love cats and nature, as well as using words. Besides the basic training in grammar and how to accurately research scientific topics from MT years, I also have a background in earth science. And now I’m living near the excellent libraries of Oregon State University in Corvallis and the University of Oregon in Eugene.

Deciding to write a book on how cats evolved was easy, though I’d never written one before. (I had done a little freelancing to newspapers in the 1980s.)

Anyway, how complicated could the basic idea be? — the dinosaurs went away sixty-five million years ago, mammals inherited the Earth, and cats eventually showed up. Simple.

I’ve been wrong before, too.

Once I started reading books and papers, I realized that the Earth changes over time, and living beings change with it. We all interact with one another all of the time, too, in very complex ways.

This plus a few megadisasters along the way, with loads of hungry animals and plants. You have to follow the food when tracking a hypercarnivore down through time. Its food depends on plants, which in turn depend on sunlight and climate (which varies with Earth’s changing surface conditions).

Also, the fossil record is very incomplete (according to one study by Johnson et al., the fossils of only about a quarter of all cats that ever lived have been found).

A few surprising facts

Earth processes can’t be ignored, either. For instance, did you know that biological effects of the K/T extinction are still affecting life on Earth today? (Krug et al.)

Yeah, lots of mind-blowing tidbits like that come up when you’re just trying to figure out a simple question: where do cats come from?

To clear up those original misconceptions:

Mammals like Gobiconodon were small, tough and pretty weird when dinosaurs ruled during Jurassic and Cretaceous times. (Image: Dallas Krentzel, CC BY 2.0)

  • Some dinosaurs survived the K/T extinction, but not the ones you might be thinking of.
  • Nobody ever inherits the Earth: we all must earn it. Even then, our place doesn’t last forever. Mammals and dinosaurs, as well as the ancestors of both these groups, have been alternating world domination for hundreds of millions of years, since Triassic times. For the moment, our side is on top.
  • Cats? It’s more like a niche for cat-like predators that family Felidae occupies today. This niche was first filled a little over thirty million years ago by VERY cat-like sabertooths called nimravids that, for all anyone knows, just suddenly appeared fully formed in North America out of nowhere. Nobody knows where or how that feline shape initially developed. Oddly enough, nimravids might have been more closely related to the caniform half of the order Carnivora!

Story, not fact

Overwhelming as it was, all this information that I stumbled into was kind of fun, and I really got into it for seven years.


One big problem, though, is that scientists may casually write a sentence that astonishes a layperson and then spend pages on jargon and graphs that they consider the really important stuff.

They’re right: that is how science works. But it’s very difficult to follow.

I really wanted to know about cat evolution, so I kept at it, compared sources, and whenever possible, read books written for laypeople by experts, such as Donald Prothero’s After the Dinosaurs and Alan Turner and Mauricio Anton’s The Big Cats and their Fossil Relatives.

Over the years, this gave me the general gist of what’s known about how cats evolved, and even more importantly, what is not known yet.

Another problem is that paleontologists and biologists don’t always agree with their peers. This is part of science, too, I’ve discovered.

If you’ve read Sir Arthur Conan Doyle’s Lost World, then look at it this way. The process of real science is exactly like the bickering between Summerlee and Challenger; Conan Doyle just exaggerated a few things and then put those characters (and their learned Society in London) into an excellent adventure tale.

Cheetah, by Michael Gwyther-Jones, CC BY 2.0; Puma, by California Fish & Wildlife, CC BY 2.0

Back to the cats. I didn’t venture very deeply into the minefields of controversy. Most of it seemed obscure details to this layperson. Whenever it affects the story — for example, whether the “American cheetah” Miracinonyx was really a cheetah or a puma — I’ll just mention the differing views.

After all, what’s amazing to us laypeople is that African cheetahs and pumas in the Americas are very closely related. Who would have expected that!

Most taxonomists and other scientists agree that this is so. That’s one of their casual throw-away lines. What they really want is to give you a mini-course in molecular biology to show you why it’s true. That’s science, but most of us would click away before they finally got to the astonishing fact.

I just want to write, as accurately as possible, a story about how cats evolved and to share some of these startling nuggets of information along the way.

But that’s all it can be: a story, not fact. The truth is in those details that make our eyes glaze over and in the few fragments of the past that have both come down to us and been recognized by professional eyes, although many of these are still under debate.

This 30-million-year-old nimravid skull is a priceless treasure to those who can imagine the North American cat-like animal that once used it. (Image: Claire H. via Wikimedia, CC BY-SA 2.0)

If you really want the facts as they’re known today, then you, too, must dive into the nearest science library for several years and try to make sense of it all (or you can check out the references used for this story, which are available at the bottom of each post).

Most of us aren’t interested in lectures and research papers. We just want to understand the world around us better.

I can help you with that.

In the next section, we’re going to see cats as they really are. Checking out Fluffy is an excellent way to start.

Then we’ll need to delve a bit into life, the universe, and everything, but don’t worry. Thirty-five (see the side bar) is a much easier number to handle than forty-two!

Featured image: teerayuth oanwong/Shutterstock


Johnson, W. E.; Eizirik, E.; Pecon-Slattery, J.; Murphy, W. J.; and others. 2006. The Late Miocene Radiation of Modern Felidae: A Genetic Assessment. Science, 311: 73-77.

Krug, A. Z.; Jablonski, D.; and Valentine, J. W. 2009. Signature of the end-Cretaceous mass extinction in modern biota. Science. 323(5915): 767-771.

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