How do dogs recognize each other? And other random thoughts.

How do dogs recognize each other?
You know what I’m talking about: dogs will ignore other species, but bark at and interact with each other. Now that doesn’t sound like an impressive recognition task, but consider that dogs have been bred over the last few thousand years into a staggering variety of subspecies, with radically different features, sizes, and proportions. How does a Great Dane know that a Chihuahua is a dog? (And vice versa; the chihuahua essentially has the brain of a wolf in the body the size of a rodent. That must be confusing.)

The first explanation that comes to mind is smell: dogs smell the same, and they have great noses, so it’s easy to tell if another animal is a dog. But I’ve seen many dogs bark at others – from behind a closed car window. So it’s something more sophisticated.

More possibilities: smell is first, sight is second, dogs only bark at similar-looking dogs if they can’t smell, etc.

Google didn’t come up with much. The best I could find is “Dogs too have their own scent and smell to establish who is who, sniffing around each other’s bodies. Dogs also use sight to first look and decide if it is a dog they are looking at and then sniff to find out if they know each other.”

I don’t have a dog (though I think they are awesome), so if you do I’d love to hear your thoughts.

Shopping by calories
I don’t know what the deal is with my metabolism, but I have to eat a ton of food each day. If I don’t eat breakfast, I won’t survive till lunch, and even after a big lunch I’m hungry by 4pm. When I go to a convenience store to grab some snacks, I often find myself shopping by calories: which item will give me the most calories per dollar? This sounds perverse, but I can’t help it. And I’ve found lately that I do this subconsciously even when I’m shopping in a grocery store! Weird. Does anyone else do this? Kent?

Obama’s Egypt speech
A thing of beauty. Read the transcript (it’s easy and pretty short). It’s nuanced, bold, and inspiring. Some people have been complaining that it’s all words, no action. But the speech itself – just words – is a huge step forward. I can’t imagine Bush even attempting this. Progress has to start somewhere.

An A-Z Music Project update
Earlier this year I started listening to all my music in alphabetical order. I had the ambitious goal of finishing by the end of the year. Well, there’s no way that’s going to happen. True, I had a very busy semester, one that didn’t leave much time for listening to music, but I’m now only halfway through the Bs (Bonnie “Prince” Billy, to be exact, and 70 hours done of 90 total in the Bs). My new projected end date: Jan 2012. Really?

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10 Responses to How do dogs recognize each other? And other random thoughts.

  1. Anonymous says:


    Dogs and many other mammals are much more sensitive to body language than humans. Despite differences in body shape, I suspect that certain body language cues are still universal among dogs. The raw size difference between a Chihuahua and a Great Dane is not an order of magnitude different from the ratio between a wolf puppy and an adult wolf. So maybe a dog is something that moves like a dog, regardless of size.

    A way to test this hypothesis would be to measure how fast a dog recognizes e.g. a crippled dog or a dog-shaped dummy vs. a healthy dog.

    • aj says:

      Re: dogs

      Yeah, and also my initial observation may be way off. Maybe dogs behind car windows bark at tons of stuff.

  2. Anonymous says:

    calories / dollar

    Have you visited NYC lately? Any chain restaurant in the city now has to show the number of calories for each item on the menu, so you could have a lot of fun optimizing. This Talk of the Town from a couple weeks ago also mentions using the measure at the new Yankee stadium:

    BTW, do you find that a calorie is a calorie, or that some food is more filling than others even with the same calorie count? I’ve found, for example, that chips seem not to be as filling as the calorie count suggests.

    • Anonymous says:

      Re: calories / dollar

      Here’s a clickable“>link for the article.

    • aj says:

      Re: calories / dollar

      Thanks for the link — I’m perennially a few months behind in my New Yorker reading. Of course, in a convenience store, the prices are lower, so you can get something like 1200 yummy calories for $2 or less if you’re careful.

      I wrote a little about calories a while back. Though it seems that what you’d really want is a notion of “functional calories”: the amount of energy you actually get from eating something. My guess is that functional calories are the product of:
      (a) the bomb-calorimeter based total caloric content
      (b) the percentage of such calories that are human-digestible (e.g. fat vs. gasoline)
      (c) the efficiency of your digestive system: the percentage of human-digestible calories that you can personally extract. (I think this varies nontrivially between people; if you give two people the same food, I anticipate that they will excrete different amounts.)
      (d) the inverse of your metabolic rate. If you have a fast metabolism, you may need to eat more.

      I am sure that nutrition scientists have a better handle on this. I’d love to measure (c) and (d) for myself. I’m guessing that I have a low-efficiency digestive system and a high metabolic rate. I’d be toast out there in the savannah.

      Though I think you’re bringing up a different question: do different foods impact satiety in different ways? Apparently the answer is yes; in particular, protein seems to fill you up more. Many modern diets (Atkins, etc.) seem to rely on this phenomenon.

      Chips are mostly carbs and fat, right? So that might explain it…

  3. snafuuu says:

    Hey, I just caught that you have a account! What’s your user name? Brandon and I can add you and determine how compatible you are (I bet you have some overlap with both of us).

    • aj says:

      Hey, it’s ajshankar. But keep in mind that I’m only scrobbling from MediaMonkey, which is where I’m playing my A-Z songs. So the selection is very skewed =).

  4. judytuna says:

    i thought it was a beautiful speech, too. such a relief after all that “axis of evil” -mongering.

    i don’t think in calories at all.

    maybe dogs act that way because they get dog-like responses. maybe like if i was in a room full of people that were only speaking in japanese, and i went around saying “hello,” and one person said “oh hey, how’s it going?” i would stop and talk to that one because we spoke the same language.

    my friend posted a thought about confining birds that this reminds me of, kinda:
    also her art is great.

  5. walther says:

    wow, shopping to maximize calories per dollar? that is hard core. i give you much respect for that. i definitely consider a utility per dollar measure when i buy food (my usual bases of comparison being a $1 McDonalds double hamburger for savory foods and the current price for a 1.75L carton of the cheapest tolerable ice cream carried by my nearest grocery store for sweet foods), but i heavily weight taste and the overall eating experience in my evaluations of utility. although, i suppose i subconsciously consider calories in that i have an overall goal of eating enough food to sustain my body and not die. actually, now that you are getting me thinking about this, maybe calories/dollar considerations do drive most of my food purchasing decisions, since 90% of what i eat these days is ramen, rice, oatmeal, beans, eggs bought in bulk, or cheap meats like Spam and hot dogs. hmmm…

    as for non-hot dog dogs, one thing i loved to do was to sit Krisy’s dog Choo in front of my laptop and show him YouTube videos that people posted of their barking dogs. i thought this was hilarious and quite interesting, since Choo would go nuts and have his full-out barking spaz attacks (like he does when he sees real dogs or rabbits) until he exerted himself to exhaustion. i don’t remember how/when i discovered this, but he always barked at grunting pigs on TV too.