The Evolution of Cats: 3.  Fluffy’s African Granddaddy

As we saw last time, laypeople have a lot of questions about Fluffy the housecat and where this quirky little animal and its relatives fit into our shared Universe.

There are still many blanks in the scientific puzzle that’s the evolution of cats, but specialists in everything from paleontology to genetics are fitting quite a few of the pieces together.

Blog posts here and eventually the book Where Cats Come From describe what I understand those experts to be saying about their work.

The easiest way to begin is by looking at Fluffy.  Housecats are built and act the same as the big cats, and they’re a lot more convenient to use as models.  (Turner and Antón)

However, this approach has its limits because ten thousand years of domestication (Clutton-Brock; Driscoll and others; O’Brien and others) and a century and a half of the cat fancy have reshaped the housecat right down to its genes.

We need to get a little more wild if we’re going to look at the evolution of all cats, including the big ones.

Let’s leave Fluffy in the house for now and visit its nearest ancestor, the African wildcat. (Driscoll and others; O’Brien and others)

Introducing Silvester

There are a lot more small cat species out there than most of us realize, but many people in Europe, Africa, and the Middle/Near East probably have heard of the group called wildcats.
These aren’t bobcats or other medium-sized or small cats.  As you can see up above, wildcats actually look a lot like housecats.

That resemblance is not a coincidence.

All wildcats share the housecat’s first two formal scientific names, Felis silvestris, followed by one of several last names. (Driscoll and others; Herbst; O’Brien and others)

In other words, this particular group of little cats is all one species, but it has different subspecies.

The most common version of Fluffy’s full scientific name seems to be Felis silvestris catus, although some experts shorten it to Felis catus.

Geneticists say that Fluffy’s closest relative is Felis silvestris lybica, the African wildcat.  Today you might see F. s. lybica  in northern Africa and the Middle/Near East.  (Driscoll and others; O’Brien and others)  

However, southern Africa’s F. s. cafra  – what looks to me, in online images, to be the same wildcat – could certainly be invited to an intimate housecat family gathering, too.

Cafra is the kitty that Marna Herbst referred to as an African wildcat in her study, as we’ll see below.

I don’t think that this third formal name matters very much to us laypeople, since we’re not talking about wildcat speciation here.  We only want a general picture of the cat family and how it evolved.  

Since it’s all one species, let’s just think of every wildcat – including those in Europe and parts of Asia  – as Silvester.  

Fluffy, of course, is back in the house or perhaps curled up on your lap right now.

Or Fluffy may be sitting there waiting for you to read what is loosely called its mind.

Are you wondering who Marna Herbst is?  

I don’t know her, but she recently did a detailed field study of wildcats in the southern Kalahari for her Ph.D.  

Of course her thesis is very technical, but it also has many interesting and easily understandable details about how Silvester lives out in the wild.  

Unless otherwise noted, all the information about African wildcats in the rest of this post is taken from that thesis.

African wildcats

The housecat’s nearest relatives, either lybica or cafra,  are found throughout Africa, except in tropical forests and the desert.

It isn’t the only small cat in Africa.

African and wild, but “Felis margarita” is not an African wildcat.

One of Fluffy’s more distant relatives, the sand cat – Felis margarita – specializes in deserts.  Unfortunately, as adorable as they are, sand cats don’t do well in captivity.  (Sunquist and Sunquist)

You probably won’t be surprised to hear that Fluffy’s African granddaddy is also a solitary hunter and uses a similar stalk-and-ambush style to catch small mammals like rodents and birds.

Silvester is a tabby, but its legs are a little longer than a housecat’s.  In Africa, north and south, it also has reddish fur behind the ears.  The males are almost a third again as big as the females.

It’s not like the Sahara, but Silvester’s Kalahari homeland in southern Africa is dry because it is part of the continent’s South West Arid Climate Zone.

The Kalahari’s mix of open areas and cover is ideal for stalk-and-ambush hunters, big and small.

Some rain falls there during the summer and autumn, but not enough to keep local rivers flowing all year round.  

Summer temperatures get up around 100 degrees Fahrenheit (37.3 degrees Celsius) and winters are chilly, with the lowest temperatures down near freezing.

Silvester’s presence in such a rugged place, as well as throughout almost all of Africa’s other habitats, shows just how adaptable Felis silvestris is. 

Seasonal changes in the Kalahari’s rainfall and temperature affect plant cover, which is mostly grass, thorny bushes, and scrubland.  

And changes in the green world in turn influence the number and variety of small plant-eaters (mostly rodents) that make up Silvester’s usual diet.  

When there aren’t enough rodents, male wildcats go after larger mammals like hares, while the females hunt birds and reptiles.

The rest of Silvester’s community includes what you would expect to find in an African wildlife refuge:

  • Wildebeests, springboks, and other large herbivores.
  • Lions, leopards, cheetahs, and hyenas.
  • Smaller predators like caracals (a medium-sized cat), foxes, jackals, and raptor birds.

Some of the raptors, by the way, may be able to carry off small wildcats.  

Researchers saw a giant owl twice try to grab a large male wildcat.  The bird couldn’t get this particular cat off the ground, and Silvester escaped  into the bushes.  Still, the owl apparently had developed a taste for wildcats.

Despite such perils, African wildcats hold their own, avoiding or hiding from big predators and chasing off smaller ones like foxes.  

They hunt mostly during the early morning and evening, with longer daytime hours during the winter when fewer prey animals are available.

Those that were studied used their eyes most often to locate prey, followed by their ears, and then their noses.

Of course, whiskers and paws come into it, too.

African wildcats spend fifteen to twenty minutes grooming themselves before and after their nightly activities.  

This will not surprise anyone who has met Fluffy.

On a hunt Silvester walks its range in a winding pattern, checking out holes and scent trails.  It might also just sit and wait for prey.   


Males sometimes walk rapidly around, spraying their local landmarks and killing prey-sized animals that they might chance upon.  

Besides spraying – which females do, too – Silvester advertises its presence by rubbing things with special glands on its face. (See Kitchener and others, “Detecting and making smells”)

Yes, your kitty loves you, but it thinks it is marking territory when rubbing up against you.

During the Kalahari study, male wildcats prowled the local dunes, while females hunted most often in the veld area of short grass and bushes where they also den up to have kittens.  

Prey is abundant in both places.  

Females in the study tended to establish territories on good hunting grounds, while males based theirs on the presence of receptive females.

Both genders spent most of their time hunting or resting, with very few social encounters of any sort except for sex or when a female had a litter.  

Usually, when two wildcats met during the study, they just stared at each other for a while and then went on their separate ways.  Sometimes one would follow the other.  

Researchers saw only one fight, between two females.

There appears to be no particular breeding season, but female wildcats in the study, which ran from 2003 to 2006, had up to four litters per year (with one to five kittens each) when prey was abundant.  

They had no litters during hard times.

How we bear our young says a lot about mammals.  How we put up with them sometimes is another matter entirely

Placental mammals

A very important fact in cat evolution is that cats are placental mammals just like we are.  Most of the familiar furry critters in the northern continents and some marine life, like whales, are part of our crowd, too.

None of us placentals has a pouch like kangaroos and other marsupials do, and we don’t lay eggs like the duck-billed platypus, which is a monotreme mammal.

Australia has a lot of marsupials, and the region is also home to the duck-billed platypus.  

In North America, at least, where the fossil record is excellent, marsupials used to dominate the world of mammals during the Cretaceous geological period. We placentals only got our turn after the K/T extinction, which was hard on marsupials.  (Prothero, 2006)

Believe it or not, the world of mammals during the dinosaur age was wide and varied.  Our history goes back over 200 million years.  (Kielan-Jaworowska)

But we’re getting ahead of the story.  Let’s save all that for the next post and finish up with Silvester.

As placental mammals, African wildcat kittens are as helpless as those of a housecat.  

The newborns stay in the den for a week or so with Mom, who only goes out for a few short hunts.

She starts making longer trips for food as the kittens grow.  After about five weeks, Mom also takes live prey back to the den to teach the kittens hunting skills.

Young wildcats in the study left their den when they were two to four months old. The research team didn’t follow them to see how they made out but noted that they generally did leave the area instead of hanging around near Mom.

Some might eventually settle down in the good hunting grounds near human settlements, as wildcats have been doing for millennia.

Their natural sociability may have been why a few African wildcats became domesticated long ago.  Unfortunately, it now threatens the whole species with extinction in the midst of life.

That is, with genetic extinction.  

This is how it works.  Even though housecats and African wildcats are genetically distinct (Yamaguchi and others), Fluffy and Silvester can and very often do interbreed.  

The resulting kittens are still F. silvestris, but do you call them housecats or wildcats?

It’s hard to say.  But one thing is certain.

There will be more hybrids and fewer genetically unique Silvesters as long as wildcats continue to mix genes with the domestic cats that people have brought into Africa.

The process can’t go on forever, and wildcats may well end up on the losing side.

Let’s pause now.  It’s time to introduce a few technical terms that can unlock, for us laypeople, the basic world of Felis, Silvester, and all their relatives.

Names and natural groups

As we’ve seen, Fluffy and Silvester are the same species, just in different subgroups.

They can still hook up because they are both Felis silvestris.  The extinction problem has to do with that third name.

Now, according to the basics of evolution theory, new species happen when one group gets totally separated from others of its kind long enough to evolve to the point where it can no longer breed with the others.  (O’Brien and Koepfli)

According to molecular studies, it’s not that simple.  

There is no single correct way to define a species, say geneticists, and the transition to a new species generally takes a while.  (O’Brien and Koepfli)

This is certainly obvious with the genus Felis:

Some of the members of this genus, like the sand cat Felis margarita, are there already.

Others, like the various flavors of Felis silvestris, are still working it out.

Silvester squared: The European wildcat is “Felis silvestris silvestris.”

So, can there really be genetic extinction during an evolutionary transition?  If not, what do you have?

Fortunately, we laypeople don’t have to figure out this brain-twister.  

It’s just a good example of the lesser-known of two very different paleontology tools.

The other tool – fossil studies – is both familiar and fascinating.

Scientists use systematics to sort fossils according to physical similarities.

As a living example, all wildcats resemble each other, but sand cats and wildcats are clearly different.  

So it’s obvious that Felis silvestris and Felis margarita are two different species.

But Felis cats have a lot more in common with each other than they do with a lion – Panthera leo.  

In other words, the genus Felis is different from the big-cat genus Panthera.

This Linnean system is binomial – one name for genus (Felis or Panthera) and the other for species (silvestris or leo).

There are other levels.  The only ones we will run across very much are families and orders.

Felis and Panthera are two genera (the plural of the word “genus”) in the cat family Felidae.  

In spite of all the levels, it doesn’t take a genius to understand a system like this.  And systematics is very handy for organizing the vast collection of modern cats.

How vast?  

The next time you’re at the library, look for the Sunquist’s book Wild Cats of the World (referenced at the end of this post).

That’s an excellent resource for both layperson and expert, with the most beautiful feline photographs I have ever seen.

But how are all those cats related?

Through genera and family.  We’ve already met Felis and Panthera (the big cats).  The other genera in the cat family are:

  • Leopardus: No, the leopard is in the genus Panthera, as odd as that seems to us.  I don’t know why scientists chose a name that’s so similar to the common name of one of the best-known big cats.  Anyway, this genus really includes ocelots and some other South American cats.  And just to make things harder . . .
  • Neofelis:  Clouded leopards. See how confusing common names can be?
  • Caracal:  As mentioned earlier, this long-legged cat lives with Silvester in the Kalahari.
  • Pardofelis:  Some small Asian cats.
  • Prionailurus:  More small Asian cats.
  • Lynx
  • Puma:  Yes, panthers are actually in this genus instead of Panthera.  Go figure.
  • Acinonyx:  The cheetah.  As we’ll see later in the series, there is a surprise hiding in this cat’s family tree.

All of these members of the cat family Felidae are called felids.  Just as all members of the dog family Canidae are canids.  

Clearly the difference between two families is profound.  But cats and dogs do have something in common, and we need at least to know its name.

Both cats and dogs belong to the order Carnivora, which also includes other feliforms and caniforms (that is, their respective relatives).

The only thing to remember here is that these carnivorans – members of the order Carnivora – all have special meat-slicing teeth called carnassials.  

That’s true even when some of them, like pandas, are now vegetarians.

Those are some carnassial teeth of a species of Pseudaelurus, one of the first cats, tens of millions of years ago.  That big curved tooth in the front is the lower canine – a fang, not a sabertooth.

You and I don’t have carnassials, but then we’re members of the order Primates.  

Carnivorans like cats and dogs, primates like us, and many other orders are all placental mammals.  

Add in the marsupials and monotremes and we’ve now got the modern class of mammals.

Yes, we’ve moved quite a way beyond the African wildcat.  Can you see a little bit how the system works?

Paleontologists, of course, go into much more detail.  (FOOTNOTE 1)

Systematics is great for classifying living and extinct beings, but it doesn’t show very much about their origins or ancestral relationships.  (Antón)

The lesser known paleontology tool does, to a surprising extent.  

It sorts living beings into natural groups of animals or plants.  Each group is considered natural because all of its members are descended from a common ancestor.  The technical name for a natural group is “clade,” so this approach is called cladistics. (Antón – FOOTENOTE 2)

Cladistics also studies fossils, but it adds in gene sequencing from living descendants and uses the concept of a “molecular clock” to build a family tree called a cladogram.  This family tree branches wherever there’s a common ancestor.  (Antón; O’Brien and Johnson; Rose)

Cladistics can work even with groups like butterflies that haven’t left much of a fossil record. (Wahlberg and others)

Cladistics is also mind-blowing for this layperson.  

Fortunately, many researchers who use the tool also have a gift for expressing their results in plain English, which I can and have followed in these posts.

The next post, for instance, will briefly mention cladistics when we look at how carnivorans might have emerged soon after the K/T extinction and also check out whether nimravines fit into the family Felidae.

We’ve met the nimravines in another series of posts at this blog.

Now extinct, the 40-million-year-old nimravines were the very first cat-shaped mammals (that we know of).  

They belonged to North America’s White River Chronofauna, described in the Age of Supereruptions posts LINK, and they also lived elsewhere in the world.

Early paleontologists thought nimravines were the ancestors of modern cats because of many amazing resemblances between the two groups. (Antón; Werdelin and others)

However, cladistics indicates a different relationship, as we will see next time.

Cladistics is a cutting-edge research tool. 

It has taken paleontologists on a time-travelling trip from Fluffy back to Silvester and even farther back, hundreds of millions of years, to a point in time when what is now southern Africa was a swampy rainforest and the first known sabertooths and other mammal-like reptiles were its top predators.  (Antón; Kemp; Sahney and others)

Far below the restless paws of Kalahari wildcats sleep some of the first mammals, the earliest dinosaurs, and perhaps even the common ancestor of both.

In the next post, we will meet them all and then follow their story forward some 270 million years, to the appearance of the first cats.

Footnote 1:  If you are curious about how experts in ancient life work with fossils, the description by paleontologist Donald Prothero in the introduction to his book After the Dinosaurs:  The Age of Mammals is very helpful.

Footnote 2:  If you want to learn more about nomenclature, check out the section on naming in Chapter 1 of Mauricio Antón’s book Sabertooth.   There is also a good discussion of it in The Beginning of the Age of Mammals by Kenneth Rose.

IMAGES (in order of appearance):

Featured image:  Martins, Rute:  Sleeping African wildcat on limb:  https://commons.wikimedia.org/wiki/File:African_Wildcat-001.jpg  CC BY-SA 3.0

Krista.  Arabian Mau.  CC BY 2.0.

Barilleaux, Charles.  “Posing Sand Kitten copy.” CC BY 2.0  https://www.flickr.com/photos/bontempscharly/4358213032

Hollis, Benjamin.  Kalahari.  CC BY 2.0. https://www.flickr.com/photos/dalangalma/8025791972/

David Corby edited by Arad.  CC BY 2.5.  Cats’ whiskers are highly sensitive to touch.  https://upload.wikimedia.org/wikipedia/commons/b/bb/Kittyply_edit1.jpg

Law, Keven.  Warning! Tiger in training!   CC BY-SA 2.0.  https://upload.wikimedia.org/wikipedia/commons/5/5a/Warning%21%21%21…Tiger_in_training…O%29%29.jpg

Viatour, Luc.  A European wildcat.  CC BY-SA 3.0.  https://en.wikipedia.org/wiki/File:Felis_silvestris_silvestris_Luc_Viatour.jpg

Ghedoghedo (photo)/Macesito (cropped).  “Fossil of Pseudaelurus.” CC BY-SA 3.0https://en.wikipedia.org/wiki/File:Pseudaelurus_teeth.png

CITED AND UNCITED REFERENCES:

AZA Lion Species Survival Plan (2012).  Lion Care Manual.  Association of Zoos and Aquariums, Silver Spring, Maryland, p. 143.

Antón, M.  2013.  Sabertooth.  Bloomington:Indiana University Press.

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  1-106.  palaeo-electronica.org/content/fc-1. 

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.

Driscoll, C. A.; Menotti-Raymond, M.; Roca, A. I.; Hupe, K.; Johnson, W. E.; Geffen, E.; Harley, E. H.; Delibes, M.; Pontier, D.; Kitchener, A. C.; Yamaguchi, N.; O’Brien, S. J.; and Macdonald, D. W.  2007.  The Near Eastern origin of cat domestication.  Science.  317:519-522.

Gradstein, F. M.; Ogg, J. G.; and Hilgen, F. G.  2012.  On the geologic time scale.  Newsletters on Stratigraphy.  45(2):171-188.

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.

O’Brien, S. J. and Johnson, W. E.  2007.  The evolution of cats.  Scientific American.  297 (1):68-75.

Rose, K. D.  2006.  The Beginning of the Age of Mammals.  Baltimore:  The Johns Hopkins University Press.
Sunquist, M. and Sunquist, F.  2002.  Wild cats of the world.  Chicago and London: University of Chicago Press.

Turner, A., and Antón, M.  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.

Wayne, R. K., Benveniste, R. E.,  Janczewski, D. N., and O’Brien, S. J.  1989.  Molecular and Biochemical Evolution of the Carnivora, in Carnivore Behavior, Ecology, and Evolution, ed. Gittleman, J. L., 1:465494.  Ithaca, NY: Cornell University Press.

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. D. W. Macdonald and A. J. Loveridge, 59-82.  Oxford:  Oxford University Press. 

Advertisements

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s