Cat tales

Our relationship with our pets has a very long history.

We know more about our connection to dogs; we've been keeping dogs (or vice versa) for at least ten thousand years, based on genetic analysis of bones found in proximity to human settlements -- and often, buried with honor.  How this relationship started is a matter of conjecture:

Wolf: I'm going to attack you, and viciously tear apart and eat your children!  You are no match for my ferocity!

Cave man: We have peanut butter, sofas, and squeaky toys.

Wolf:  ... I'm listening

Domestic cats, on the other hand, have more uncertain origins.  They were known to have been revered in ancient Egypt, and in fact the much-loved protector goddess Bastet is always depicted with a cat's head.  The ancestors of today's house cats are thought to be the Libyan wildcat (Felis lybica), a small felid which is still found in most of Africa, the Middle East, and central and southern Asia.  They were probably encouraged to live alongside humans for their use as mousers, and eventually became companion animals, just as dogs had earlier.

What's certain is that after that relationship formed, wherever humans went, their pets came along.  A very cool series of studies a while back used patterns of cat genetics -- in particular, the prevalence of the polydactyly gene and the gene that controls swirled tabby coat coloration -- to figure out the paths of migration taken by their human owners.  And just this week a fascinating paper appeared in the journal Science looking at how domestic cats first arrived in China, much more recently than you might think.

The first written reference to cats in China comes from the Tang Dynasty, and dates to the middle of the seventh century C.E.  It's a rather horrifying story.  An imperial concubine name Xiao ran afoul of a higher-ranked wife named Wu Zetian (Wu eventually was to become empress outright).  Wu had Xiao condemned to death -- by having her hands and feet chopped off, then to be drowned in a barrel of wine -- and before the sentence was carried out, Xiao said, "In my next life, may I be reborn as a cat, and Wu Zetian as a mouse.  I will then seize her by the throat to extract my revenge!"

Wu wasn't impressed, and had her rival executed anyhow.  History doesn't record any subsequent rebirths as cats and/or mice.

The earliest domestic cat bones found in China are from an archaeological site called Tongwancheng, and date to only around 1000 C.E.  There were earlier feline specimens, but they all seem to be the remains not of modern domestic cats but of the leopard cat (Prionailurus bengalensis), a small south Asian wildcat species (that recently was crossbred with the domestic cat to produce the Bengal breed), and which probably lived alongside humans but was never truly domesticated.

Bengal cat [Image licensed under the Creative Commons User:Lightburst, Paintedcats Red Star standing, CC BY-SA 4.0]

As far as domestic cats, they seem to have arrived in China via the Silk Road.  Bones found in Kazakhstan, dating to the ninth century C.E., have a mitochondrial DNA signature that links both to later Chinese cats and to cats in the Middle East -- suggesting that merchant travel between the two is how cats arrived in east Asia.

Once there, they established a place in Chinese culture as the favorite pet of the wealthy.  Like the earlier study of cat genes and human migration, this one has an odd filigree having to do with how human selection influences evolution.  In Chinese culture, white is a symbol of purity, and white animals are especially revered.  This gave Silk Road merchants an incentive to find and transport white cats -- a practice over a thousand years ago which has left its mark all these centuries later.  This selectivity of importation is probably why today a disproportionate number of modern Chinese cats are white (or have white patches).

So we move, and we take our pets with us, and that changes both them and us.  It's a very old connection, and one many of us cherish deeply.  Think of that next time you cuddle with your kitty or puppy -- you're taking part in a relationship that goes back thousands of years, and was important enough even in those rough times that it drove commerce.  So even before the existence of mail-order places like Chewy, where we can spend inordinate amounts of money pampering our furry friends, our bonds with our pets were still a deeply important part of our lives.

****************************************

Steve, Steve, Jennifer, and Onesimus

I remember running into the idea of changing trends in name popularity when I saw a New Yorker comic back in the seventies.  It showed a typical first grade class photo, including the teacher, and the caption said, "Top row: Steve, Steve, Jennifer, Jennifer, Steve.  Middle row: Jennifer, Steve, Jennifer, Steve, and Steve.  Bottom row: Jennifer, Jennifer, Steve, Steve, Jennifer, and Mrs. Bertha Q. Wackenhorst."

Interestingly, as that particular trend goes, during my last ten years of teaching, I had only a handful of Jennifers in my classes, and barely any Steves.  But I bumped into a more recent iteration of the same phenomenon with a photo of five handsome, affluent-looking white college guys, all smiles and tans and perfect hair.  The caption read, "Left to right: Hayden, Trayden, Kayden, Grayden, and Brayden."

In my own case, I was named after my father, but he was named by his mom, who allegedly said -- and having known her well, I can easily hear her saying it -- "He may be stuck with a French last name, but he damn sure is going to have a Scottish first name!"  Which is how I ended up with an odd amalgam that is still strangely fitting of my actual roots.

Things get even more complicated when you start throwing in other languages.

Names come and go, something that really became apparent when I started doing research into genealogy.  Various relatives and ancestors from my family tree include Ulysse, Anicet, Roxzella, Orsa, Laodice, Odressi, Donathilde, and Hiram.  A friend of mine, for whom I did some genealogical digging, descends from a guy named Onesimus Futch, which sounds like an insult.  ("How dare you, you onesimus futch!")  

My wife's family is largely Eastern European Jewish, and she has Avish, Baruch, Gittel, Scholem, Chaia, Dvora, and Mordechai.  The really weird ones, though, are in my wife's non-Jewish ancestry, which hailed from England and goes back to the Anglo-Norman nobility.  She has an ancestor named, I kid you not, Marmaduke de Thweng.  Another was Johanna Ufflete.  But by far my favorite is Benedicta de Shelving, which would make a great name for the patron saint of interior decorators.

Always keep in mind that however strange your name is, it could be worse.

The topic comes up because of some recent research out of the University of Michigan which looked at naming trends both in children and in pets, and found that it could be modeled using a concept from evolutionary genetics called frequency-dependent selection.  The idea here is that the success of a specific phenotype -- and thus its trending toward becoming more or less common -- depends on how common it already is.  It can go either way; in positive frequency dependence, the trait has better success the more common it is.  (A good example is warning coloration, where a poisonous or venomous species advertises its presence with bright colors; the tactic only works if there are enough dangerous, brightly-colored individuals that predators learn to leave them alone.)  There's also negative frequency dependence, where the success of common phenotypes is poorer.  (An example is apostatic selection in a species of common British garden snails that have a variety of color patterns; studies showed that predators favored the more familiar-looking ones, so rare color patterns had a better survival rate.)

Naming trends tended to show a negative frequency dependence; when names become common, new parents (or new pet owners) tend to choose something more distinctive (or else spell it differently, which is why I had students named Michaela, Mikayla, Mikaela, Makayla, and Mekayla, fortunately not all in the same class).  Names become trendy for a while, but following the time-honored principle of "I want to be unique, just like everyone else," if the trend peaks too high, it goes into an equally precipitous fall.

"This is really a case study showing how boom-bust cycles by themselves can disfavor common types and promote diversity," said study co-author Mitchell Newberry.  "If people are always thirsting after the newest thing, then it's going to create a lot of new things.  Every time a new thing is created, it's promoted, and so more rare things rise to higher frequency and you have more diversity in the population."

Still, something that is too odd never does catch on.  I've seen the name Trasimond in nineteenth century Cajun French records, but I've never known one in real life, and that particular name seems to have always been a bit of an outlier.

You have to admit, though, that it's kind of euphonious.  Better than Onesimus Futch, anyhow, not to mention the unfortunate Mr. Zopittybop-Bop-Bop.  Given those as choices, I'll stick with Gordon.  I might even stick with Marmaduke de Thweng.  At least that one has a certain insouciance.

**************************************

Why the sad face?

Springboarding off Saturday's post about non-human animals having emotions, today we're going to look at a study that came out a couple of weeks ago in Frontiers of Veterinary Science that demonstrates that not only do animals have emotions, they've evolved to be able to play on ours.

In a paper with the rather intimidating title "The Application of Geometric Morphometrics to Explore Potential Impacts of Anthropocentric Selection on Animals' Ability to Communicate via the Face: The Domestic Cat as a Case Study," animal behaviorists Lauren Finka and Mark Farnsworth (of Nottingham Trent University), Stelio Luna (of São Paulo State University), and Daniel Mills (of the University of Lincoln) looked at an interesting phenomenon; the way human selection of animals for pets has led to the animals evolving traits that trigger a nurturing response in the owners.  A particularly interesting one is the "inner eyebrow raising muscle," which in domestic dog breeds is far more highly developed than in wild dogs, and which causes the furrowed brow "sad puppy" look any dog owners out there will no doubt recognize immediately.  My lovable rescue dog Grendel was the past master of this particular expression:

No, he was not spoiled.  Don't even suggest such a thing.

People seeing Grendel usually took one look at him and said, "Oh, you poor poor puppy!  Why the sad face?  Here, puppy, have a cookie."  Which, of course, led him to understand that looking sad got him what he wanted.

Evolution for the win.

The study that came out a couple of weeks ago, however, took a look at cats, which in general have less emotionally expressive faces than dogs do.  My wife's cat, Geronimo, who died a couple of years ago at age eighteen, had a spectrum of facial expressions that ran the gamut from "I'm pissed off" to "I hate you," occasionally reaching the level of "fuck off and die."  I know this is ascribing human thoughts to a non-human animal, but whenever Geronimo looked at me, his yellow eyes narrowed to slits, I always came away with the expression that he was plotting to disembowel me in my sleep.

But the current study shows that most domestic cats have a wider range of emotional communication than Geronimo did.  Interestingly, what the researchers called "pain features" -- movements of the face indicative of distress -- were often present in "baby-faced" breeds like Persians even when the animals were not actually in distress, while long-faced breeds like Siamese showed fewer "pain features" even when the animal was in pain.  I wonder if this is why Siamese cats have a reputation for being "aloof" and "independent," and Persians a reputation for being in need of pampering?

The authors write:

The ability of companion animals to readily solicit care from humans is obviously advantageous.  However, it is possible that permanently vulnerable looking individuals might have a diminished capacity to clearly indicate when care is or is not required, as well as to display other information relevant to their actual state or intentions.  Thus, if certain cat breeds are being selected to display “pain-like” features on their faces, these features may serve to solicit unwanted or inadequate attention from their caregivers.  More generally, such types of anthropocentric selection might lead to increased anthropomorphic tendencies.  If, for example, the animal has the appearance of an expression which humans find relatable on some level, even if it is not necessarily reflective of that animals' affective state, it may be used to attribute emotions or characteristics to them.  For example, “grumpy cat” a cat made famous by her coverage on social media, achieved her moniker due to her perceived “frowning” facial appearance.  However, this was likely a result of a combination of her feline dwarfism and paedomorphic [infant-like] features, rather than an expression of her irritability.

One interesting point the authors make is that one possible reason that cats in general have fewer facial cues to solicit nurturing from humans is that they've been in domestication as companions for a far shorter time than dogs have.  The human/dog relationship goes back millennia; and while cats have been used as mousers for centuries, their use as companion animals is of fairly recent origin.  In fact, a large percentage of current domestic cat breeds are under a hundred years old -- in other words, if you trace most "pure-bred" cats' ancestry back two hundred years, they all descend from a population of generic-looking felines that began to be heavily selected when people started keeping them in their homes, and expecting something more out of them than just ridding the house of rodents.

In any case, as the authors point out, the advantage to the pet is obvious.  In our case, our dogs play us like fiddles.  One of our current dogs, a lovable big galoot named Guinness, knows that to get what he wants all he has to do is put his head in my lap and just stand there.  I've tried ignoring him, but he knows that patience always gets him what he wants (usually petting) in the end.  If I make eye contact with him, the tail starts wagging, because he knows he won.

As usual.

But as my wife points out, the fact that they've evolved to yank on our heartstrings isn't entirely a one-way relationship.  We get companionship and love and lap-warming, and there's real value in that.  So really, I'm perfectly okay with being used.  A petless home would be a lot cleaner and quieter, but it would also be a lot colder, lonelier, and sadder.

******************************************

As a biologist, I've usually thought of myself as immune to being grossed out.  But I have to admit I was a little shocked to find out that the human microbiome -- the collection of bacteria and fungi that live in and on us -- outnumber actual human cells by a factor of ten.

You read that right: if you counted up all the cells in and on the surface of your body, for every one human cell with human DNA, there'd be ten cells of microorganisms, coming from over a thousand different species.

And that's in healthy humans.  This idea that "bacteria = bad" is profoundly wrong; not only do a lot of bacteria perform useful functions, producing products like yogurt, cheese, and the familiar flavor and aroma of chocolate, they directly contribute to good health.  Anyone who has been on an antibiotic long-term knows that wiping out the beneficial bacteria in your gut can lead to some pretty unpleasant side effects; most current treatments for bacterial infections kill the good guys along with the bad, leading to an imbalance in your microbiome that can persist for months afterward.

In The Human Superorganism: How the Microbiome is Revolutionizing the Pursuit of a Healthy Life, microbiologist Rodney Dietert shows how a lot of debilitating diseases, from asthma to allergies to irritable bowel syndrome to the inflammation that is at the root of heart disease, might be attributable to disturbances in the body's microbiome.  His contention is that restoring the normal microbiome should be the first line of treatment for these diseases, not the medications that often throw the microbiome further out of whack.

His book is fascinating and controversial, but his reasoning (and the experimental research he draws upon) is stellar.  If you're interested in health-related topics, you should read The Human Superorganism.  You'll never look at your own body the same way again.

[Note:  if you purchase this book using the image/link below, part of the proceeds goes to support Skeptophilia!]

Tracing the lapse of ages

The evolutionary model is one of the most powerful explanatory devices in biology.  It has led to discoveries that simply blow the mind -- such as the fact that dinosaurs didn't go extinct after all (we still have 'em -- we just call 'em birds).  As Richard Dawkins has demonstrated, all you need is an imperfect replicator (DNA) and a selecting agent (the environment) and you can create massive changes in way fewer generations than you'd think.

Of course, sometimes that may not result in an improvement.

I want to tell you today about two fascinating examples of evolutionary conundrums, both about our friends the erstwhile dinosaurs -- and similar occurrences which had nearly opposite results.

First, let's look at scrub jays.

These smart, pretty birds, bright blue with gray markings, are made up of two populations.  The first (and largest) is represented by Woodhouse's Scrub Jay (Aphelocoma woodhouseii):

[Image licensed under the Creative Commons Peter Wallack, Western Scrub Jay, Santa Fe, CC BY-SA 3.0]

The second is the Florida Scrub Jay:

[Image licensed under the Creative Commons Mwanner at the English language Wikipedia]

Pretty similar, right?  Odd, then, that these two photographs were taken 2,700 kilometers apart -- and there are no scrub jays of any kind in between.

Given the fact that the western scrub jays (which include three other species besides Woodhouse's) are a much larger and more diverse population than their Floridian cousins, it's likely the Florida Scrub Jay's ancestors came from the west rather than the reverse.  But how?  They're not migratory, so they didn't get blown off course on migration (which happens -- for three years running a Pacific Loon showed up in Cayuga Lake in upstate New York).  So what caused the split -- and when?  There's apparently been little drift in the populations since the division occurred, given the fact that they're pretty similar still, but that might be low selection, not short time spans.

The bottom line is, we don't know.  The scrub jays are a textbook example of allopatric range distribution -- related populations that have no range overlap.  And while in some cases these peculiarities have been explained, this one has not.

Even odder -- and virtually the opposite in end result -- came out of a genetic study of skeletons of the adzebills (Aptornis spp.), a pair of species native to New Zealand which went extinct from overhunting after the colonization of the islands by the Maoris.  They were impressive birds -- flightless, predatory, just under a meter tall, with the heavy, sharp, downcurved bills that gave them their common name.

Skeleton of Aptornis defossor in the Auckland Museum [Image licensed under the Creative Commons Auckland Museum, Aptornis defossor (AM LB544) 601651 (cropped), CC BY 4.0]

Their general shape led scientists to think they may be related to moas -- enormous flightless birds that went extinct right around the same time as the adzebills did.  But here, appearance and size are misleading.  The study, published last week in Diversity, has shown the genetics of the adzebills indicates their closest living relatives are a group of birds in Africa...

... the flufftails.

White-spotted Flufftail (Sarothrura pulchra)  [Image licensed under the Creative Commons Francesco Veronesi from Italy, White-spotted Flufftail near Kakum NP - Ghana 14 S4E2889 (16010066588), CC BY-SA 2.0]

"A lot of past genetic research and publicity has focused on the moa, which we know were distant relatives of the ostrich, emu, and cassowary," said study co-author Dr Kieren Mitchell of the University of Adelaide.  "But no one had analysed the genetics of the adzebill, despite a lot of debate about exactly what they were and where they came from."

Study co-author Trevor Worthy of Flinders University added, "We know that adzebills have been in New Zealand for a relatively long time, since we previously discovered a 19 million-year-old adzebill fossil on the South Island...  A key question is whether they've been present since New Zealand broke away from the other fragments of the supercontinent Gondwana or whether their ancestors flew to New Zealand from elsewhere later on."

But... look at these two.  (The birds, not the researchers.)  Even the most diehard scientific type might raise an eyebrow at these being closely related.  However, consider my first example -- the wolf and the pug.  Selective breeding of cats and dogs has produced enormous differences in only a few hundred years.  Imagine you were an alien biologist, come to Earth to catalog all the species of life on this planet, and you ran across a chihuahua and a Saint Bernard.

My guess is if you told the alien biologist they were the same species, he/she/it would laugh in your face.  But they are, in fact, genetically very close, and in fact are even theoretically interfertile.  (Although what a Saint Berhuahua would look like kind of boggles the imagination.  Plus, the mechanics of the conception are a little problematic.  I mean, if it was a male chihuahua and a female Saint Bernard, would they, like, give him a stepladder or something?)

An imperfect replicator plus a selecting agent plus time can create wonders.  It seems fitting to end this post with a quote from Charles Darwin's The Origin of Species which I think sums it up brilliantly:

It may metaphorically be said that natural selection is daily and hourly scrutinising, throughout the world, the slightest variations; rejecting those that are bad, preserving and adding up all that are good; silently and insensibly working, whenever and wherever opportunity offers, at the improvement of each organic being in relation to its organic and inorganic conditions of life.  We see nothing of these slow changes in progress, until the hand of time has marked the lapse of ages.

***********************************

This week's Skeptophilia book recommendation is a tour-de-force for anyone who is interested in biology -- Richard Dawkins's The Ancestor's Tale.  Dawkins uses the metaphoric framework of The Canterbury Tales to take a walk back into the past, where various travelers meet up along the way and tell their stories.  He starts with humans -- although takes great pains to emphasize that this is an arbitrary and anthropocentric choice -- and shows how other lineages meet up with ours.  First the great apes, then the monkeys, then gibbons, then lemurs, then various other mammals -- and on and on back until we reach LUCA, the "last universal common ancestor" to all life on Earth.

Dawkins's signature lucid, conversational style makes this anything but a dry read, but you will come away with a far deeper understanding of the interrelationships of our fellow Earthlings, and a greater appreciation for how powerful the evolutionary model actually is.  If I had to recommend one and only one book on the subject of biology for any science-minded person to read, The Ancestor's Tale would be it.

[If you purchase the book from Amazon using the image/link below, part of the proceeds goes to supporting Skeptophilia!]