Photos of the day: real tweets and a felid

July 17, 2014 • 2:03 pm

Here is what tweets should really be instead of those 140-character snippets of self-promotion, beach selfies, and rage-fighting that afflict us on Twi**er:


The books were found by my friend Andrew Berry from Harvard, teaching an evolutionary biology course at Oxford this summer.

And, as lagniappe, a local sign. Cave Hollow Village is apparently near Hannibal, Missouri, home of the young Mark Twain. Here’s its sign:


My question is this: Why not “Pop. 7“?

h/t: Gregory

18 thoughts on “Photos of the day: real tweets and a felid

    1. JAC is probably typing with one finger, while trying to book the taxi for the airport with one hand and tighten the straps on the suitcase of Hili-treats with the other three hands. Feet. Limbs. Whatever.
      Isn’t that what graduate students were invented for – being professorial dogs-bodies (/contra/ cats-bodies, requiring constant fussing over and provision of treats. And tuna.)?

      1. Apparently so. Just as well; it was a link to some sensationalist “wacky story of the day” item about a couple who had trouble with a newly-adopted cat.


        1. Thanks for the clarification. Also the apparent confirmation that quotes are no longer nesting where they should be.

  1. Please tell me where I can read more about the genetic makeup of Chihuahua and Great Dane. In your discussion of ring species, I thought you said the Chihuahua and Great Dane cannot inter breed.

    1. I think you might be operating under a bit of a misconception.

      First, to address your first sentence, this would be a good place to start:

      However, the juxtaposition of those two sentences implies that you think that speciation occurs when some sort of genetic mutation happens that prevents male and female germ cell chromosomes from stitching up. While that’s one path to speciation, I don’t think it’s at all common.

      With Great Danes and Chihuahuas, the problems for interbreeding are first mechanical; consummation of the act might not be physically possible. Next, even if you resorted to artificial insemination, it is unlikely that a Chihuahua mother would survive the pregnancy.

      There are many wild animals that exhibit similar barriers to interbreeding, with cats being a good example. There have been successful lion / tiger hybrids, but it’s notorious for being a tricky challenge.

      That brings us to the most important criteria for speciation: even if it would be possible to hybridize the organisms in a laboratory environment, if there is no evidence of actual gene flow in the wild, you’ve got two separate species. And, often, in the real world, this happens for reasons only indirectly related to genetic mutation. A typical example would be a species separated by geography, such as the salamanders Jerry discussed in his recent post on ring species. Another common example is for sexual selection, often coupled with geographical variation, to lead to individuals from one subpopulation preferring to mate with each other, and for those preferences to grow more significant over time. Eventually, that subpopulation only ever tries to mate with those matching those characteristics, even though it would produce perfectly viable offspring with its close relatives if those behavioral barriers weren’t in place.

      Hope that helps….



      1. it is unlikely that a Chihuahua mother would survive the pregnancy.

        I’m not aware if (or why) anyone has actually tried the obvious experiment, but isn’t it also plausible that the pups would not survive the pregnancy, being unable to get sufficient nutrition for their growth from the bitch? Which would lead to low birth weight, or slow development of an undersized litter.
        Do canids (or felids, for that matter) do the same re-absorption of unsupportable foetuses that rabbits do (the only mammals with which I have practical experience of breeding ; I should re-phrase that, before the wife hits me)? Come to think of it, how common is that strategy in mammals in general?

        1. Were there any notorious Nazi veterinarians? It’d be right up their alley, doing such experiments down at the concentration pound.

          1. From what I have read, Hitler was an animal lover and was opposed to experimentation on animals. People of course, were fair game.

  2. With a population of 6, that sign should read at least “and 4 cats.” And that’s only because I give some allowance for allergies.

  3. Tweet of the day is what I hear when I first turn on the radio in the morning. Today was the tree pipit.

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