The Domestic Cat Lineage


Here is a repost from this past April about Fluffy and relatives. I’ve updated it with a few links about the other “Felis” cats (except the Chinese mountain cat, which will be in the eBook).

Fluffy, top center, is surrounded by its closest relatives in the cat family:

  • Southern Africa’s black-footed cat, Felis nigripes, top right
  • The Chinese mountain cat, F. bieti, bottom right
  • A wildcat, bottom center, in this case the European wildcat F. silvestris
  • A jungle cat, F. chaus, native to parts of Africa and southern Asia, bottom left
  • A sand cat, F. margarita, from the deserts of North Africa or Arabia, relaxing in a sunbeam, top left.

See end of post for photo credits/permissions.

Individual posts with species facts will follow over the next five weeks (excepting Fluffy, of course–there are two eBooks out on our friend already!).

As noted in the second eBook, Fluffy’s own scientific name is either Felis catus or Felis silvestris catus, depending on which expert you consult.

These beauties all have the same first scientific name: Felis.

According to Nyakatura and Bininda-Emonds, that moniker also belongs to the Pallas cat, but they say that this weird little feline from south central Asia doesn’t belong in the domestic cat lineage.

So . . .

What is Felis?

Short answer: Setting aside Pallas cat controversies for the moment, it’s a genus name that happens to be shared by all members of the domestic cat lineage.

Details: It’s important not to get hung up on scientific names, though they can be useful. There are other ways to herd cats.

“Genus” and “lineage,” for example, are actually terms from two completely different approaches that often (but do not always) coincide.

Genus is a way to classify living beings; lineages are all about descent.

As for the word “felis,” it developed from a job description.

Back in Roman times, feles meant any small animal used to control rodents and other domestic pests. Stoats and weasels were the go-to feles for centuries, but when Egypt became a Roman province, some of its domestic cats were employed this way, too.

Cats actually weren’t as good as the weasels and stoats because they weren’t the right shape to pursue a rat or other miscreant into its burrow, but they were friendlier and they didn’t wander off all the time.

Their association with Roman, as well as Egyptian, gods also brought prestige to owners.

Felix, on the other hand, means “happy.” (Wikimedia, public domain)

In his masterwork Naturalis Historia, Pliny the Elder used the Latin form felis for cats. It may have been a popular name for domestic cats by then, but they were also known as cattus.

Fast-forward through the decline and fall of Rome and Byzantium, as well as much more Western history.

In the 1700s another great naturalist — Sweden’s Carl Linnaeus — invented the now familiar binomial scientific naming system of “Genus” followed by “species” while cataloguing all life on Earth for his great work, Systema Naturae.

Linnaeus used both old Roman words for the house cat, dropping one of the t’s for some undoubtedly good reason: Felis catus.

All cats were now Felis and their species names varied. Lions were Felis leo, lynxes were Felis lynx, and so forth.

It worked well for the scientific needs of the day. But down through the centuries, species and subspecies names got rather complicated (don’t worry, we don’t need to get into those).

“Genre” is something else entirely. (Wikimedia, public domain)

Some researchers recognized the need for more genera (the plural of “genus”), too, since cats were widespread and very different from one another.

The cheetah obviously needed its own genus and so eventually became Acinonyx — full name Acinonyx jubatus.

For the rest, it came down to who could roar (Panthera, i.e., the big cats, like Panthera leo and Panthera tigris [tiger]) and who purred (Felis — basically, every cat except the cheetah and big cats). (Pocock)

This three-tier system worked throughout the 20th century, even after issues with the roaring/purring definition came up.

But as the 21st century approached, better genetics research tools became available, along with much greater computing capabilities for data processing and statistical analysis.

As a result, more accurate distinctions have drawn between various groups of related cats. Today, as many as 18 genera are recognized. (Kitchener et al.)

Domestic cats and a few others still maintain the time-honored Felis, though. Because of its association with Fluffy, this genus name is never going to disappear.

But human traditions are now supplemented with hard science.

This technique for studying evolution isn’t limited to the cat family. Here’s a cladogram for mammals. Such trees are useful to get a quick idea of general relationships, but their accuracy is never guaranteed. (Fred Hsu via Wikimedia, CC BY-SA 3.0)

It’s possible to draw cat family trees, called cladograms.

These are based on which feline groups share a common ancestor and therefore are very closely related.

In practice, phylogenetics, as this is called, is quite complicated, but the basic idea behind it is straightforward. Every branching point is a common ancestor.

There are several different cat family trees out there. Results vary somewhat according to the methods used and the types of samples that are studied.

Nevertheless, most experts agree that the feline tree contains eight branches and that big cats were the first lineage to branch off.

Per Kitchener et al., big cats include the genera Panthera and Neofelis (the clouded leopard).


One of these things is not like the others. (Left to right: “Panthera leo,” big cat lineage, by Tambako the Jaguar, CC BY-ND 2.0; Socks the Cat, National Archives via Wikimedia; “Neofelis diardi,” big cat lineage, by Charles Barilleaux, CC BY 2.0.

Sure, there can be more than one genus in a lineage.

The Linnaean system is all about classification based on physical characteristics. Most of the time it does correspond pretty closely with the family tree (as with Felis), but not always (the big cats).

Phylogenetics, on the other hand, is based strictly on line of descent, though there are differing ideas about how to define common ancestors. Other complexities include the uncertainties involved with fossil and molecular data analysis (see Benton & Ayala in the source list for details).

Modern taxonomists try to keep both Linnaean rules and evolutionary history in mind when naming things, but you do get a Neofelis in with the pantherines every now and then.

It’s really just a happy coincidence that the most recent cat family lineage — the one Fluffy belongs to — consists of every member of the genus Felis (except possibly the Pallas cat, as we’ll see below).

How do they know that these cats are closely related?

Short answer: Through fossils and molecular markers. Plenty of debates are raging, but the domestic cat lineage is fairly solid; the only question here is where the Pallas cat, a/k/a Manul, fits in.

Details: It’s hard to know when to stop while tracing back the family Felidae. After all, evolution is open-ended, and it doesn’t happen in a vacuum.

Where do you draw the line and shout “First!”?

Per the fossil record, Proailurus, at the start of the Miocene, is the oldest known cat.


If you’d rather skip geologic time, which can be pretty mind-boggling, colors work just as well. Temps during the epochs we’re talking about are in green. Cats do go back a LONG way. Unrelated to this post but still interesting are the facts that modern cats and sabercats came into their own during the black-line part (our own immediate ancestors showed up then, too), and that the ice ages, not surprisingly, are the blue line. Beyond colors and names of epochs, though, I don’t know about this scale. (Image: Glen Fergus via Wikimedia, CC BY-SA 3.0)

And Stenogale probably at least was related to cats. That takes us back into the Oligocene.

But cat-like sabertoothed hypercarnivores called nimravids thrived even earlier than that, in the Eocene.

Barbourofelis was perhaps the most extreme sabertooth that ever lived. Did Smilodon’s ancestors get the idea for big teeth from critters like this? (Image: Ghedoghedo via Wikimedia, CC BY-SA 3.0)

Fast-forwarding into the Miocene again, the first cats — yes, even sabercats — had to play second fiddle to yet another group of cat-like hypercarnivores called barbourofelids.

Over deep time, adaptations to environmental changes as well as food-web interactions, and random events including (but not limited to) mutations, all shaped some of these early predators into cats.

How?

It’s very unclear, that far in the past.

Even today, conservationists can’t track every habitat and behavioral detail they need to know in order to understand and protect tigers and other endangered species.

That’s with the aid of modern technology and the ability to go look at their living subjects in the field (if the boffins can find them).

Most all that remains of those Eocene, Oligocene, and Miocene cat-like predators and early cats are a few bony fragments and some individual teeth.

This makes it very difficult to study the evolution of cats through fossils alone.

If paleontologists are really lucky, they may find a skull or an ancient hole of some sort that protected a skeleton from scavengers and the elements long enough for it to fossilize.

They get very excited when such an opportunity arises.

The exploring party which I had sent into the John Day River valley under the direction of Mr. Jacob L. Wortman, in 1879, examined the bad-lands in the locality known as The Cove. In passing the bluffs on one occasion, a member of the party saw on the summit of a pinnacle of the crag what appeared to be a skull. The large shining objects supposed to be teeth attracted his attention, and he resolved to obtain the specimen. He, however, was unable to climb the cliff, and returning to camp narrated the circumstance. The other men of the party successively attempted to reach the object, but were compelled to descend without it, and in one case, at least, the return was made at considerable peril. A later attempt, made by Leander S. Davis, of the party, an experienced collector, was more successful. By cutting notches with a pick, in the face of the rock, he scaled the pinnacle but at considerable risk to limb and life.

— E. D. Cope (see source list)



Totally worth it.

Cope was able to identify a new nimravid species from that skull and a few other clues.

It’s amazing what paleontologists can learn, even from fossil fragments and individual teeth, by applying the rigorous rules of systematics.

They’re slowly filling in the overall picture of how cats evolved. But fossils only go so far — far enough to classify groups by their appearance, but not enough to see the evolutionary paths the animals followed.

For that, you need DNA.

Genetic material degrades quickly, so we’re not ever going to get some from multi-million-year-old barbourofelid or nimravid fossils.

Meet Cinnamon, an Abyssinian cat whose DNA was used to sequence the feline genome. (Dr. Kristina Narfstrom via Wikimedia, public domain)

The sabercats lasted until around 11,000 years ago, but even that’s too long ago. Only a little of their DNA has survived, barely sufficient to prove that sabertooths were cats but belonged in a different, now extinct subfamily of Felidae. (Barnett et al.)

However, modern cats are walking archives of genetic history.

Researchers are busy exploring this rich source of information, now that they have the tools for it.

Advanced statistical analysis software enables them to convert the data they collect into cladograms (family trees, basically).

Again, each branch stands for a hypothetical line of descent. And each branching point is a common ancestor for the lines that follow.

If you go far enough back with your cladogram, you’ll get to the common ancestor for people, cats, and sponges, whatever that was.

But let’s just talk about the domestic cat’s lineage. Where did it branch off? What was its common ancestor? (Spoiler: They’re still studying this.)

First off, the oldest “Felis” fossils go back more than 4 million years. (Werdelin et al.) And that is right around the time that many phylogenetic studies suggest the modern lineage began.

You don’t see that coincidence between fossil and phylogenetic dating in the other lineages.

Detailed results, however, do vary somewhat from researcher to researcher. After all, this complex work can be approached in different ways and analyses are open to different interpretations.

Nevertheless, there’s almost 100% agreement that black-footed cats, wildcats, jungle cats, and sand cats all sit on that cladogram branch with Fluffy. (The Chinese mountain cat is a little iffy, but not extremely so.)

They’ve even found a “sister group” — the leopard cat lineage of four small Asian cats.

Why “sister”?

Because the ancestors of both lineages each split from the Felidae tree at roughly the same time (though exactly when is controversial: two popular numbers are 6.2 million years ago [ Johnson et al.] and 11.6 million years ago [Nyakatura and Bininda-Emonds]).

Those studies do agree that modern species in the leopard cat lineage developed a little earlier than those in “Felis,” the newest cats on the block.

They broke the mold with this one. (Image: Sander van der Wel, CC BY-SA 2.0)

What no one has established beyond a doubt yet is where the Pallas cat fits in.

According to Nyakatura and Bininda-Emonds, molecular analysis shows that this adorable hairball, which they call Felis manul, is on its own: a “sister” to both the leopard cat and domestic cat lineages.

Johnson et al., on the other hand, report that the Pallas cat, known to them as Otocolobus manul, is a member of the leopard cat lineage.

There’s nothing we laypeople can do to resolve the issue, of course, but it’s good to see how house cats fit into the family Felidae — through a group of near relatives that inhabit diverse places, from swamps (the jungle cat) to the Sahara (sand cats), and are also found close to home in many Eurasian and African places (wildcats).

And the connection continues on, through the leopard cat lineage (and possibly Manul) all the way up the tree to the oldest lineage of all: the big cats.

Next week, we’ll start out with the jungle cat in a series looking at the members of the the domestic cat lineage in more detail.


Featured image:



Sources:

Barnett, R.; Barnes, I.; Phillips, M. J.; Martin, L. D.; Harington, C. R.; Leonard, J. A.; and Cooper, A. 2005. Evolution of the extinct sabretooths and the American cheetahlike cat. Current Biology, 15(15):R589-R590.

Benton, M. J., and Ayala, F. J. 2003. Dating the tree of life. Science, 300: 1698-1700.

Cope, E. D. 1880. On the Extinct Cats of America. The American Naturalist. 14(12): 833-858.

Flynn, J. J., and Galiano, H. 1982. Phylogeny of early Tertiary Carnivora with a description of a new species of Protictis from the middle Eocene of northwestern Wyoming. American Museum Novitates, Number 2725.

Heptner, V. G., and Sludskii, A. A. 1972. Mammals of the Soviet Union, volume II, part 2: Carnivora (hyaenas and cats). Moscow: Vysshaya Shkola Publishers. English translation by Rao, P.M., 1992. General editor: Kothekar, V. S. New Delhi: Amerind Publishing. https://archive.org/details/mammalsofsov221992gept

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.

Kitchener, A. C.; Breitenmoser-Würsten, C.; Eizirik, E.; Gentry, A.; and others. 2017. A revised taxonomy of the Felidae: The final report of the Cat Classification Task Force of the IUCN Cat Specialist Group. https://repository.si.edu/bitstream/handle/10088/32616/A_revised_Felidae_Taxonomy_CatNews.pdf

Nyakatura, K., and Bininda-Emonds, O. R. P. 2012. Updating the evolutionary history of Carnivora (Mammalia): a new species-level supertree complete with divergence time estimates. BMC Biology. 10:12.

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

Pocock, R. I. 1951. Catalogue of the Genus Felis. London: British Museum–Natural History. https://archive.org/details/catalogueofgenus00brit

Salesa, M. J., Antón, M., Morales, J., and Peigné, S. 2011. Functional anatomy of the postcranial skeleton of Styriofelis lorteti (Carnivora, Felidae, Felinae) from the Middle Miocene (MN 6) locality of Sansan (Gers, France). Estudios Geológicos, 67(2):223-243.

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.

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



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