The Evolution of Cats: 1. Why A Cat?

Experts say that when dogs first evolved, they lived in trees and looked something like a civet. (Rose)

It’s true that cats evolved later than dogs, but when they first appeared they looked a lot like modern cats.  And long before the first true cat evolved, fully developed cat-like nimravids bounded onto the scene.

Fossils from those early days are rare, so nobody knows how nimravids developed, but ever since then that beautiful feline shape has prowled the forests and plains of Earth.

This story also has a human side.

Unlike any of the other four-legged animals that we have tamed and manipulated, dogs and cats have been our friends, not our property.

Homo sapiens hasn’t shared a common ancestor with Canis or Felis for as much as 165 million years, according to one estimate (Benton and others), but dogs do seem to be closer to us at heart than cats are.

Connecting with a dog takes you back to Pleistocene nights when people shared meat around the campfire with the faithful animals who had helped to harvest it during the day and who now huddled together with everybody else for protection in firelight and fellowship during the dangerous hours of darkness.

No such instinctive bond is possible with cats.

After all, it was never good when a night-prowling Pleistocene sabertooth got in amongst the group around the campfire.

But let’s not forget that the big cats—both the sabertooths and the ancestors of today’s lions, tigers, and other large- to medium-sized predators—also preyed upon small felines.

Yes, little cats were around back then, among them, the first known members of the group Felis.  (Werdelin and others)

Evolution of housecats—the short version

Wildcats—Felis silvestris—and other small cats had little protection from their king-sized relatives.  They didn’t gather in groups, and they certainly weren’t pack hunters.

Since most cats stalk and ambush their prey (Werdelin), if the little ones wanted to eat, they had to sit quietly in ambush for extended periods, all the while exposed to bigger predators.

mackerel_tabby_camouflage
Wildcats evolved that beautiful tabby fur pattern to hide them from everybody, not just prey.

Female wildcats had to do all that plus carry, bear, and raise a litter of kittens . . . alone.

No wonder that wildcats bear kittens not according to season but only when there is plenty of food available!  (Herbst, Chapter 4)

Despite these challenges, wildcats survived the ice ages, thrived, and ultimately spread out to fill many small predator niches in Europe, Africa, and Asia.  (Yamaguchi and others)

As that happened, a few African (and maybe Asian) wildcats (Yamaguchi and others) gravitated toward human settlements.

Why not?  There was a secure food supply there.  As well, construction of all those newfangled farms and towns, springing up for the first time in Earth’s history, created innumerable hidey-holes where a little cat could do anything from have kittens and raise them to just relax for a few hours and enjoy a relatively safe nap.

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Refuges are hard to find in the wild.  This black-footed cat is smaller than African wildcats and must hide even from them.  (Herbst)

People got the best of this deal.  (Clutton-Brock)  Pest control in homes, barns, religious buildings, libraries, granaries, and other vital places improved everybody’s health and also made civilization a lot easier to establish.

But there was more to it than business.

Some people were drawn to the tamer wildcats because they were just as beautiful as the big cats, but you could safely hold them.

And then, sometimes, the cat’s purr would let you feel the deep rumble of the wild, as well as hear it, for an hour or more at a time.  Both cats and humans loved that!

Civilization begat spare time, and more people began to appreciate cats for what they are, not just for what they do.

No one knows precisely how or when wildcats turned into domestic cats (Felis silvestris catus)—let alone at what point the first “cat person” came along—but certainly the spiritual feline-human connection really took off in Egypt some 3,600 years ago.  (Herbst; Yamaguchi and others)

It has continued in one form or another, ever since.

How to see a cat

Today it’s okay to look into a housecat’s eyes and observe that mad little core of untouchable wildness.

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It’s okay because their ancestors never hunted ours.

What we can see in those gem-like eyes is the boundary between two worlds.  Today’s housecats belong not only to the human family but also to their own.

As Turner and Antón put it (in scientific terms):

The livingroom pet has the same overall body plan [as a lion or leopard], with long limbs, claws, and sharp teeth well suited to catching, dispatching, and eating its prey.  It behaves, hunts, and deals with its food in a thoroughly catlike manner, and is therefore as much a member of the [cat] family as is the lion, the leopard, or one of the extinct sabertooths.

Every domestic cat brings the wild into our homes, where it walks the fine line between two very different worlds gracefully, naturally, and a little crazily.

Of course, what you see in a cat depends, to some extent, on how you feel towards it.  Most of us fit into one of these three different categories:

  • A cat’s a cat, what’s the big deal?
  • Hate cats.
  • Love them.

Fortunately, cats are cool enough to impress even the first two types of people.

Don’t believe it?

Run, cat, run

Some people have very strong feelings about the feline world, one way or the other.  But perhaps you are among those who can either take cats or leave ’em.

You might still be more in tune with them than you realize.

Have you ever had this experience?  You’re driving through the suburbs some evening around twilight.  Up the road a ways, a diminutive four-legged creature suddenly crosses the road and disappears into the bushes.  It’s gone by the time you get there, but you know it was a small cat.

How?  The light is too dim to see much detail and the animal was too far away and moved too quickly for the headlights to help much.

The give-away was how it moved, with a quick, slinky trot.

  • A small dog, jackal, or dingo might have that sort of shape, but it would have loped across the road.  Caniform legs often are long enough for these predators to chase prey over long distances.
  • Civets, mongooses, and some other feliforms (as well as certain caniforms, like weasels) are cat-shaped, but they need short, very strong legs to catch burrow-dwelling prey.  One of these animals would have bounded across the road in short leaps as your car approached, since that’s much faster than trying to scurry to safety on such stubby legs.

At a distance, then, you recognized a small cat by its locomotion.  No other animal has that beautiful compromise (Kitchener and others) between a pursuit hunter’s light, speedy limbs, and the digger’s powerful but short legs.

That’s a very academic way to think of cats, but once you see a feature like that, it makes a lot of practical sense.

Cats need stronger leg muscles than dogs so they can control stalking movements (Taylor) as well as hold onto struggling prey once they have caught it.

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This leopard’s hunting style shows why cats like habitats with a combination of trees and open spaces.  (Martin)

Muscles are most effective on short bones, but a cat’s leg bones have to be long enough to cover a lot of ground as the animal prowls its territory each night.  Those legs also must be capable of short bursts of speed at the kill.  (Herbst; Kitchener and others)

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Just right for pouncing and scurrying at the same time!

Of course, not all feline limbs are the same length.  Lifestyle makes a big difference. (Turner and Antón)

Housecats are about average, but a few of their relatives have carried the leg thing to extremes, as cats are wont to do.

Cats for cat haters

Instead of feeling neutral about them, you might dislike cats and wonder how otherwise sane people can dote on an obvious assasin like Fluffy, with its blunt face, sharp teeth, and borderline personality.

Congratulations!  You have spotted the one simple fact that has shaped all cats and their evolution—their need to murder other living beings.

This is not usually the first thing that a felinophile or disinterested person notices.

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Shown above: Some of Nature’s most efficient killers.  Seriously.

Take that face, for example.

Modern cats have snouts that are shorter than a dog’s because they have fewer teeth—basically, just canines to hold and kill the prey, a row of incisors to grasp the victim and, later on, to remove its meat from the bone; and sharp, scissors-like cheek teeth called carnassials to rapidly open up a carcass and eat as much as possible before a scavenger comes along.  (Biknevicius and Van Valkenburg; Kitchener and others)

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Every cat, near a cat-hater. (Note the upper and lower canine teeth and the straight row of lower incisors. The carnassials don’t show up well in this view. They sit behind the canines just in back of a short gap where molars used to be.)

 A short jaw and very few teeth, all of them specialized for processing meat, are unmistakable signs of a hypercarnivore.  (Holliday and Steppan)  Unlike dogs, which can and do devour just about anything, cats need to eat a lot of meat or they will die.

The biomechanics of that shortened jaw also means that cats can deliver a very strong bite.  (Holliday and Steppan)

That’s not so good when you’ve ticked off Fluffy, but it makes sense out in the wild.

Hunting dogs inflict slashing wounds.  (Biknevicius and Van Valkenburgh)  As the pack chases prey, each dog darts in, attacks, and then swerves out of the way of defensive horns or hoofs.  Eventually the victim drops not only from exhaustion but also from loss of blood.

That actually seems rather cruel.  At least cats get it over with quickly, though of course only for selfish reasons.

A cat hunts alone and therefore risks tooth fractures and subsequent starvation every time it goes out for food.  This is why they kill their prey with a very precise, stabbing bite to the victim’s neck or throat area—that’s what the canines are for.  Nerve damage or suffocation, respectively, quickly brings down the animal.  (Biknevicius and Van Valkenburgh; Martin; Kitchener and others)

This type of bite loads the cat’s teeth, jaw, and skull almost to the max, but only briefly, if everything goes the cat’s way.  (Biknevicius and Van Valkenburg)

Sometimes it doesn’t.

In one survey, for instance, 20 percent of the modern big-cat skulls studied had broken teeth, and half were those precious canine teeth.  (Kitchener and others)

At least today’s cats have it better than their prehistoric ancestors.  Back in the late Pleistocene, the tooth breakage rate was about three times higher for all large predators, including cats.  (Van Valkenburgh and Hertel)

So, why should a cat-hater be expected to care about such obscure details of feline dentistry?

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This sabertoothed nimravid had a few more cheek teeth than modern cats, but it was also a hypercarnivore.

 That’s why.

Sabertooths were awesome, and they are also extinct.  This means that none of your cat-loving friends is ever going to expect you to hold one on your lap and pet it.

Yes, there were housecat-sized sabertooths (Werdelin and others), as well as giants like Smilodon populator, whose last name means “he who brings destruction.” (Antón, quoting P. Lund)

Most big cats over the last 40 million years have had saberteeth.  (Kitchener and others)  Really, the only unusual thing about sabertooths is that there aren’t any around today.  (van den Hoek Ostende and others)

In the next four posts there will be lots of details about sabertooths, since they roamed the Earth for so long: how they might have evolved, lived, hunted, and ate, and possible reasons why the various sabertoothed cats of the last ice age went extinct.

Cat lovers

I have saved you for last, knowing that you wouldn’t mind.  You’re interested in a cat’s legs, saberteeth, and anything and everything else that reveals more about these beautiful animals.

I’m a cat lover, too, and I hope you will enjoy the subsequent posts in this series.

When I began to research my book about cat evolution (hopefully coming out in the fall of 2017), I learned things about cats that would interest everybody and also many facts that help cat lovers understand their pets better.

For one thing, cats and people (and all other mammals) have the same sort of body plan: a spine and four limbs, and so forth.  So did the dinosaurs, for that matter, but obviously there were more differences than similarities.

Still, mammals and dinosaurs emerged at the same time, hundreds of millions of years ago.  We really have a very long history.

That’s why I am going to start the next post in this series on cat evolution with one foot in the present—the Kalahari in southern Africa, where wildcats most closely associated with domestic cats still live—and one foot in the past.  Far below those roaming wildcats, the earliest known mammals and dinosaurs now sleep side by side.

There was nothing like a cat around to survive the K/T extinction 65 million years ago, but not long after that catastrophe the founders of the order Carnivora, which includes cats and dogs, appeared.

Why did some of them turn into nimravids and, a bit later, cats?

Not a lot is known about it yet, but I will touch on these times in the next post, as well as visit more familiar ground—the Eocene/Oligocene Age of Supereruptions described in previous blog posts here.  That’s when the nimravids showed up.

But we will continue the North American part of the story past the White River chronofauna and into the Miocene and the days of the North American “cat gap.”

And we’ll take a look at Pseudaelurus—one of the first true cats.  It developed in the Old World and eventually migrated into basin-and-range country from Eurasia, its probable land of origin.

There is much more to the story of cat evolution after that, too:

  • Ghosts—the first true sabertoothed and conical-toothed cats; their relationship, so far as it’s known, to Pseudaelurus; and the unknown lineages that connected them to prehistoric and modern cats.
  • The diaspora of big and small cats across the planet.
  • Ice-Age cats, and the people who knew them, drew pictures of them, and possibly drove many of them into extinction.
  • The arrival of little Felis the Cat and what happened after some of these little cats joined their fate to ours.

I hope that you will enjoy reading these posts as much as I am enjoying writing them.

As always, thanks for your interest.

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IMAGES (in order of appearance):

Meowy.  “Van Kitten.” CC BY 2.5. http://en.wikipedia.org/wiki/File:KittE_a_Van_cat_kitten.jpg

Fowler and Fowler.  “Mackerel tabby camouflage.”  The original uploader was Fowler&fowler at English Wikipedia [Public domain], via Wikimedia Commons. http://commons.wikimedia.org/wiki/File:Mackerel_tabby_camouflage.JPG

Barilleaux, C.  “Suspicious Black-Footed Cat.”CC BY 2.0. http://www.flickr.com/photos/bontempscharly/4263324037/in/photolist-nD6m5Y-nXw8uM-mgPuJn-o7KFAs-dajPQP-ntzwT4-7Jd3DA-dajPRK-hMXqcf-ayR4T1-ecfKhW-dHM4NT-7uJDGR-9uFZhe-EhYwjB-bkGmth-oSWTGy-oBA3WW-Hd5vbR-dcDxvY-4zi1s4-cA9RFQ-dFAk9Y-9zYoWD-7Nff23-dFAkRo-dFAoHA-dFAjpb-dFAmxm-e8oKA9-dFuZnP-oYxXXz-9uFYnc-xwPwt-4zngZq-4zi1MP-dFAqHh-ocWFAH-6Ug7oQ-6JcHYQ-kFKZT6-oZ4sm-aZRrXB-8rQ6km-9zYEka-rYx94j-5Ap6du-pbwd3p-cA8H5C-8rM2wx

Delbos, A.  “Cats in a barn, 6 months later.”  CC BY 2.0. http://www.flickr.com/photos/alesk/2314907071

Sharp, C. J.  “Leopard (Panthera pardus pardus) stalking in the Okavango Delta, Botswana.”  CC BY-SA. 3.0.  https://commons.wikimedia.org/wiki/File:Leopard_stalking_Botswana.jpg

Mandt, T.  “Katze.”  CC BY 2.0.  https://www.flickr.com/photos/calvinshmelvin/3814932231

Cat montage (clockwise from upper left):

Orias1978.  “Angry Cat.”  CC BY 2.0.  http://www.flickr.com/photos/63478301@No5/14564413376 (Link no longer active)

Zell, H.  “Hoplophoneus primaevus 01.” CC BY-SA 3.0.  https://commons.wikimedia.org/wiki/File:Hoplophoneus_primaevus_01.jpg

Hisashi from Japan.  “Cats greeting by rubbing against each other.”  CC BY-SA 2.0.  https://commons.wikimedia.org/wiki/File:Two_orange_tabby_cats_greeting_by_rubbing-Hisashi-01.jpg\

REFERENCES:

  • Benton, M. J.; Donoghue, P. C. J.; Asher, R. J.; Friedman, M.; Near, T. J.; and Vinther, J.  2015.  Constraints on the timescale of animal evolutionary history.  Palaeontologia Electronica, 18.1.1FC; 116; palaeo-electronica.org/content/fc-1.  Last accessed September 15, 2016.
  • Biknevicius, A. R., and Van Valkenburgh, B.  1989.  Design for killing: craniodental adaptations of predators, in Carnivore Behavior, Ecology, and Evolution, ed. Gittleman, J. L., 2:393-428.  Ithaca, NY: Cornell University Press.
  • Clutton-Brock, J.  1989.  Competitors, companions, status symbols, or pests:  a review of human associations with other carnivores, in Carnivore Behavior, Ecology, and Evolution, ed. Gittleman, J. L., 2:375-392.  Ithaca, NY: Cornell University Press.
  • Herbst, M.  2009.  Behavioural ecology and population genetics of the African wild cat, Felis silvestris Forster 1870, in the southern Kalahari.  PhD thesis, University of Pretoria.  http://repository.up.ac.za/bitstream/handle/2263/28963/Complete.pdf?sequence=6 Last accessed November 4, 2015.
  • Holliday, J. A., and Steppan, S. J.  2004.  Evolution of hypercarnivory:  the effect of specialization on morphology and taxonomic diversity.  Paleobiology.  30(1):108-128.
  • Kitchener, A. C., Van Valkenburgh, B., and Yamaguchi, N.  2010.  Felid form and function, in Biology and Conservation of Wild Felids, ed. D. W. Macdonald and A. J. Loveridge, 83-106.  Oxford:  Oxford University Press.
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  • Turner, A., and M. Antón.  1997.  The Big Cats and Their Fossil Relatives:  An Illustrated Guide to Their Evolution and Natural History.  New York:  Columbia University Press. 
  • van den Hoek Ostende, L., Morlo, M., and Nagel, D.  2006.  Fossils explained (52):  Majestic killers:  the sabretoothed cats.  Geology Today.  22(4):150-157.
  • Van Valkenburgh, B., and Hertel, F.  1993.  Tough times at La Brea: tooth breakage in large carnivores of the late Pleistocene.  Science, New Series.  261(5120):456-459.
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  • Werdelin, L., Yamaguchi, N., Johnson, W. E., and O’Brien, S. J.  2010.   Phylogeny and evolution of cats (Felidae), in Biology and Conservation of Wild Felids,  ed. Macdonald, D. W.,  and Loveridge, A. J., 59-82.  Oxford:  Oxford University Press. 
  • Yamaguchi, N., Driscoll, C. A., Kitchener, A. C., Ward, J. M., and Macdonald, D. W.  2004.  Craniological differentiation between European wildcats (Felis silvestris silvestris), African wildcats (F. s. lybica)and Asian wildcats (F. s. ornata): implications for their evolution and conservation. Biological Journal of the Linnean Society.  83:47-63.
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