Cats

By Razib Khan | February 9, 2007 11:54 pm

cat.jpgThe “domestic” cat, Felis silvestris catus, has been with us for nearly 10,000 years. Recently, a 9,500 year old burial of a human and their companion cat was discovered on Cyprus. Cats are not indigenous to the island, so it seems that the presence of this cat must be owed to human intervention in some manner. Though we are used to thinking about how humans shaped cats through selective breeding the recent data on Toxoplasma gondii suggests that cats might have an impact on human behavior that could explain cultural differences! Some intellectuals have posited that the selection of companion animals (i.e., cat cultures vs. dog cultures) is reflective of their values, but the irony might be that the animals (cats) might shape those values. A friend once quipped that we did not domesticate the cat, the cat domesticated us. Though functional explanations that cats served to rid agricultural communities of vermin are plausible (the extermination of cats in Medieval Europe might have encouraged plague becaues of the reproduction of black rats), it may also be that the domestic cat’s “niche” is the human propensity toward small friendly furry creatures. In any case, it seems that the dominant ancestral contribution to the domestic cats the world over is from the North African Wildcat, Felis silvestris libyca, though contributions and admixture with other subpecies of Felis silvestris, such as the European Wildcat, seem likely (certain European breeds exhibit tabby markings remiscient of local wild populations, and hybridization is common through the range of the two species where they overlap so admixture and introgression has occurred).


green.jpgThere are differences between the domestic cat and its wild cousins and ancestors. Like most domesticated subspecies its brain is smaller, and it is also relatively social and naturally tame. We are used to considering cats solitary creatures, and in the wild the various silvestris subspecies tend to be loners unless mating or raising kittens, but the existence of feral cat colonies attests to the fact that there are important behavorial differences between domesticated cats their wild cousins. Unlike wildcats domesticated cats can live together (as attested by tens of millions of cat owners), even if they are not pack animals such as dogs or herd animals like many herbivores. Some evidence exists that hybridization with European Wildcats results in offspring who tend to be less naturally tame or sociable than the domesticated cat, implying some level of recessiveness to these characteristics (perhaps because of loss of function mutations which can be complemented by one “wild type” allele at various loci in the heterozygote hybrid ). Another interesting hypothesis regarding the nature of domestic cat evolution is that they have been bred for neotenous characteristics. The same evaluation has been made of dogs, and yes, even humans. Not only do many cats exhibit the morphological characteristics of kittens, some of their behavorial biases might be due to a retention of the necessity of toleration of others in the litter.
HAH.jpgOf course cats come in many varieties, and there are official “breeds.” I’m to understand that though there are some ancient physical types (e.g., the Persians are an old breed), the vast majority of certified breeds emerged within the last 100 years, though some were conscious attempts to resurrect the physique of older lines and there is often ambiguity in regards to the question whether these breeds are partially descended from their model antecdents. Because of the interest in breeding (for cat shows, etc.) we know a few rules of thumb in regards to cat genetics. First, the “longhair” type seems to be recessive to the “shorthair.” That is, shorthair cats may produce longhair offspring in the litter, but longhair cats bred together should only produce longhairs because their genotype is homozygous. Wildcats are invariably shorthaired, and it seems that the reason here is clear, as longhairs tend to require a great deal more daily grooming, and owners of these breeds are often advised to aid in cat hygiene through regular brushing. The fitness implications of being longhaired seem pretty unambiguous, though there is some speculation that a few breeds, such as the Norwegian Forest Cat, might have developed longhair because of its superior insulation properties. Another interest of cat breeders is color and pattern of coat, and here there is one locus which exhibits a dominance-recessive inheritance pattern, the Agouti gene. In short, the “tabby” pattern which is common in many cats and is also the norm in the wild is dominant to “solid” color patterns. Agouti is a peptide which is an antagonist to the MC1R locus (which has a central role in the regulation of various pigment production genes), and the banding patterns exhibit a similar genetic architecture throughout mammalian taxa. The camouflage value of a striping pattern is well known, so it is reasonable that in the wild this would be the norm. There are also many color genes which have been localized for cats. The polygenic nature of this characteristic shouldn’t be particularly surprising, humans are less varied in skin pigmentation (i.e., we modulate one pigment, the two forms of melanin, to generate a black to white range in a scalar manner) and that trait is polygenic. One can see a truncated chart of the genetic architecture for cat coloration here (the reality is more complex, but you can conceptualize the nature of polygenic multiallelic inheritance). An interesting point to note is that white blued-eyed cats are more likely to be deaf, and this tendency toward greater likelihood for deafness among depigmented individuals is found across mammalian taxa, evidence of deep seated pleiotropy in the genetic pathways.
Note: I have used the terms dominant and recessive promiscuously in this post. I do so with some trepidation, but the terminology is so ingrained in cat breeding that I was hesitant to introduce what I feel would be a more precise lexicon.
final.jpg

CATEGORIZED UNDER: Genetics
ADVERTISEMENT
  • http://www.idiocentrism.com John Emerson

    The fishing cat looks much like a house cat but has special fur which makes it comfortable in the water. Seeing a happy cat in the water looks bizarre.
    I read once long ago that most American cats have been shhown to have been descended for the cats of a single port city in England, possibly Bristol. The article explained that American cats’ coats were controlled by only a few genes: stripe, agouti, tortoiseshell/calico, and a few for color. Can’t find the article — Natural History or the Smithsonian, I think.

  • http://truthspew.blogspot.com Tony P

    I’ve had cats all of my adult life. Matter of fact I won’t keep live in a house without a cat.
    They aren’t as aloof as people make them out to be. At this moment, my little Angie is asleep in my lap. But she’s also a grand champion mouser and living on restaurant row, the area is littered with mice and rats.
    So yes, she’s a companion animal that earns her keep. It’s a win-win if you ask me.

  • Francesca

    Thanks! This is a very good article. I have found information on how cats behave in colonies. There are some interesting papers on it.

  • http://www.accidentalblogger.typepad.com Ruchira Paul

    The smallest feline is a masterpiece. – Leonardo Da Vinci
    Thanks Razib, for doing what I have refrained from doing (with considerable effort) so far – writing about cats. I read somewhere that modern blogging has its roots in a group of cat lovers posting pictures and snippets about their cats on the web. Tempted as I have been to run a regular “Kat” column of my own, the only time I posted a picture of my cats on the blog was an artist’s rendition (my own) of my two cats. I invite your readers to visit.
    Yes, definitely there are cat people and dog people.
    Some famous cat lovers:
    Leonardo Da Vinci, Isaac Newton, Lord Byron, Tagore, Charles Dickens, T.S Eliot, Mark Twain, Edgar Allen Poe, Hemingway and many more of the creative types.
    Notorious feline haters:
    Alexander the Great, Julius Caesar, Ghenghis Khan, Napoleon, Benito Mussolini and no surprise, Adolf Hitler.
    But mostly people are not clearly either/or in this matter. Some are equal opportunity animal lovers like me, with greater propensity towards one or the other. Others are indifferent, with no particular likes or dislikes. But I have noticed that cat lovers tend to spread their affection more liberally towards other species. Fervent dog lovers on the other hand are more likely to be “dogmatic” about withholding their kindness towards animals with a greater sense of their own autonomy. (In other words, some tend to be control freaks.)
    As a life long cat lover (I love dogs too), I find all feline activities charming, even when they are doing nothing, which is often. So naturally, I derived much enjoyment from the antics of this fastidious cat.

  • http://thegreenbelt.blogspot.com The Ridger

    Here’s the opening of Twain’s Pudd’nhead Wilson:

    The scene of this chronicle is the town of Dawson’s Landing, on the Missouri side of the Mississippi, half a day’s journey, per steamboat, below St. Louis.

    In 1830 it was a snug collection of modest one- and two- story frame dwellings, whose whitewashed exteriors were almost concealed from sight by climbing tangles of rose vines, honeysuckles, and morning glories. Each of these pretty homes had a garden in front fenced with white palings and opulently stocked with hollyhocks, marigolds, touch-me-nots, prince’s-feathers, and other old-fashioned flowers; while on the windowsills of the houses stood wooden boxes containing moss rose plants and terra-cotta pots in which grew a breed of geranium whose spread of intensely red blossoms accented the prevailing pink tint of the rose-clad house-front like an explosion of flame. When there was room on the ledge outside of the pots and boxes for a cat, the cat was there– in sunny weather–stretched at full length, asleep and blissful, with her furry belly to the sun and a paw curved over her nose. Then that house was complete, and its contentment and peace were made manifest to the world by this symbol, whose testimony is infallible. A home without a cat–and a well-fed, well-petted, and properly revered cat– may be a perfect home, perhaps, but how can it prove title?

    How can you deny it?

  • http://thegreenbelt.blogspot.com The Ridger

    About tabbies – Oliver Lawson Dick writes in his Life and Times of John Aubrey (in the University of Michigan edition of Brief Lives):

    Even tabby cats were once newfangled novelties. W. Laud, A. B. Cant. was a great lover of Catts, Aubrey reports, He was presented with some Cyprus-catts, i.e. our Tabby-catts, which were sold, at first for 5 pounds a piece: this was about 1637, 0r 1638. The fashion thus started resulted in a change which Aubrey strongly resented. I doe well remember, he says crossly, that the common English Catt, was white with some blewish piednesse: sc. a gallipot blew. The race or breed of them are now almost lost.

    I had one of those “common English catts” once – now I have a silver tabby. Interesting how things like this change, isn’t it? And can you imagine paying 5 pounds for a cat in 1637!

  • LK

    “can you imagine paying 5 pounds for a cat in 1637!”
    My fuzzy little thing was free to any home willing to take him. Can’t imagine anyone paying me for him.

  • dougjnn

    Razib–
    Some intellectuals have posited that the selection of companion animals (i.e., cat cultures vs. dog cultures) is reflective of their values, but the irony might be that the animals (cats) might shape those values.
    I’d love to hear more about that. Though I realize most or all of it is likely to in the nature of non-scientific evidence and anecdote and speculation.

  • http://www.accidentalblogger.typepad.com Ruchira Paul

    Where is my comment on Cat gone? Please find it Razib.

  • http://www.scienceblogs.com/gnxp razib

    Where is my comment on Cat gone? Please find it Razib.
    the ‘spam’ filter seems be rather strict of late…
    I’d love to hear more about that. Though I realize most or all of it is likely to in the nature of non-scientific evidence and anecdote and speculation.
    click toxoplasma gondii above. it isn’t non-scientific, though speculative.

  • http://www.xenogere.com jason

    As someone who’s lived with cats for many years, this was a great post, Razib. I’m always happy to learn something new about my feline owners.
    While I knew about the blue-eyed white cat propensity for deafness, is that similar to the calico tendency to be mostly female with only sterile males? I doubt it goes back as far but am curious if we’re talking about the same genetic function, especially since that’s also related to color.

  • http://www.scienceblogs.com/gnxp razib

    calico genetics here. deafness is diff. cuz it doesn’t seem deterministic, there is an increased propensity, but not an inevitability. that suggests that the pleiotropy is embedded in a complex genetic network with a lot of other factors that need to occur. the depigmentation is likely one factor which increases the chance of some genetic pathway breaking. calico color though is a pretty straightforward mendelian trait i seems (x-related).

  • http://akinokure.blogspot.com Agnostic

    Some famous cat lovers:
    and many more of the creative types.

    Probably has to do w/ the Toxoplasma bug dialing up their level of Neuroticism — you know how those emotionally tempestuous artist types can get! Scientists are usually more mellow, but the upper crust might be more in the direction of artists’ level of emotionally instability.
    Re: white spots & deafness — could this be a balanced polymorphism that protects against a pathogen that enters the melanocytes of the skin / inner ear? There is suggestive evidence that congenital deafness in humans is probably a protection against a skin infection. The Wikipedia article says that the deafness-albino link is pretty widespread among mammals — maybe one of us started it, and after coming into contact w/ each other, it jumped species, increasing selection pressures for lighter skin?
    If we knew roughly when the loss of function alleles began rising in frequency in the various species, we might be able to find out who started it all.

  • keil

    Interesting. My brother has a cat born from a fairly old feral population, and it does seem less tame and more rugged.

  • Patricia

    This is extremely interesting. I have 25 cats, 20 of which (whom for those of us who think our cats are people) are members of an extended family. I have noticed that cats love being in family groups. They are extremely sociable, and are happy to interact affectionately with the two resident dogs. I think we force isolation on cats by taking home one little kitten and expecting it to grow up happy and well balanced. Another plus for my family group – they do not wander and they do not hunt, as my garden full of native birds will attest. I have also discovered other fascinating facts, like toms make very loving fathers if allowed to bring up their litters. And they still like to go to their mothers for a cuddle even when fathers themselves. I could go on forever, but I won’t. Best wishes to all cat lovers everywhere.

  • http://birdadvocates.blogspot.com/ Bird Advocate

    Thank you, scientific based information about felines is almost rare as hen’s teeth. So much published “fact” about them is filled with rhetoric caused by differing agendas.

  • http://www.mythusmageopines.com/wp Alan Kellogg

    More recently people have breed domestic cats to species of small African cat other than the African Wild Cat. The savannah cat for example is a mix of domestic with serval. The breed started with experimental breeding aimed at producing domestic cat/serval hybrids that could breed true, then tweaking things to produce an animal with the general appearance of a serval and the behavior of a house cat.
    Where feline behavior is concerned, note that among wild species individuals range from completely antagonistic, to animals that rather enjoy human company. One example of this being a pair of cloud leopard brothers at the San Diego Zoo. One would tolerate people, but wouldn’t put up with any untoward familiarity, the other loved attention, and would let himself be cuddled from time to time. Were we to breed cloud leopards for companion animals it’s far more likely we’d be breeding animals like the friendly brother.

  • Randy Stillwater

    I HATE U AND UR CATS !!!!!!!!!! JK I LOVE CATS BUT NOT UUUUUUUU !!!!!!!!!!!!!!!!!!!!!1

  • erin

    i love ur cats so much , but my cats are very unek ! and i like my better than urs sorrryy !

  • http://ero.com eli

    fags

  • David Harmon

    Uh-oh — Alan, did you close the screen-door after you? Looks like we got some squirrels in here…. 😉
    Ridger: can you imagine paying 5 pounds for a cat in 1637!
    Well, this CFA FAQ indicates that purebred cats today go for $300-$500 or so, and I imagine exotic breeds would be more. (I know purebred dogs can range into four and five figures!)
    Regarding the sociality of wild cats, it’s worth remembering that several of the “big cats” are quite social. My guess is that most of the cat family can choose different social structures, to suit their ecological pragmatics. That is, widely scattered food yields solo or paired hunters, while large prey or defensible feeding sites (dumps) let them assemble into prides/clowders, and so forth.

  • David Harmon

    I like that silver longhair… it reminds me of a “dorm cat” back in college, who was so fuzzy that it took the residents several years to realize that “she” was a “he”….

  • http://dog courtney

    Cuteeeeeeeeeee!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

NEW ON DISCOVER
OPEN
CITIZEN SCIENCE
ADVERTISEMENT

Discover's Newsletter

Sign up to get the latest science news delivered weekly right to your inbox!

Gene Expression

This blog is about evolution, genetics, genomics and their interstices. Please beware that comments are aggressively moderated. Uncivil or churlish comments will likely get you banned immediately, so make any contribution count!

About Razib Khan

I have degrees in biology and biochemistry, a passion for genetics, history, and philosophy, and shrimp is my favorite food. In relation to nationality I'm a American Northwesterner, in politics I'm a reactionary, and as for religion I have none (I'm an atheist). If you want to know more, see the links at http://www.razib.com

ADVERTISEMENT

See More

ADVERTISEMENT

RSS Razib’s Pinboard

Edifying books

Collapse bottom bar
+