Wednesday, June 24, 2009
But the nose! THE NOSE!! It's the best thing ever. Seriously. Look what it can do underwater:
Don't act like you're not impressed.
Even better than blowing some seriously sweet bubbles though, the nose acts like an eye. It's a bit dark in tunnels, as you will have learned from watching "The Descent", which makes finding food a bit tricky (unless you are a big scary monster with a taste for man-flesh). As you may note, the eyes on these guys are a bit hard to find, and their ears really aren't much better equipped. Sense of smell isn't exactly something to write home about either...but their touch reception on the end of those rays is amazing. Each one of the rays is covered with Eimer's Organs, which are fun little bazoomba-looking nerve endings:
Good stuff. The rays closest to the mouth have the most nerve fibers going to these organs, so these rays are the most sensitive. When I say that the star works like an eye, I really mean it. The moles jam their nose around in their tunnels until it touches something interesting - just like how you would scan bar patrons in search of someone who is not a complete douchebag. Once the prey is located by the peripheral rays, the mole brings the center rays into contact with it to be sure of what it is, or to go back to the bar example, turning your eyes toward the bright red blob in the corner and bringing it into focus (I really don't recommend this, as red blobs almost invariably turn out to be some asshole you met once at a party in college, but I digress).
So, not only do these central rays on the nose act as a kind of tactile fovea for these moles with tons of peripheral nerves supplying it, they also takes up a huge portion of their brain to process the information coming from it. One quarter of the sensory cortex is taken up by just this one ray. To give you some comparison, here is a map of the human sensory cortex where all of the body parts are drawn to scale with amount of representation they have in the brain:
Here's another super-fun representation, just in case you were sleeping too well at night:
Those of you who survived freshman psychology will recognize these as homunculi, which I'm almost positive translates loosely into "Wow, God surely does have a sense of humor to devote so much sensory area to lips and so little to the genitals." Seriously, I was expecting something more like this:
Although something less wrinkly would have appealed to my aesthetic sense a bit more. Also, I can't imagine the data they are losing with this by not including the foreskin...*tsk tsk*
Um, where was I?
Oh yes. Tactile foveation in the star nosed mole. Pretty amazing brain organization for something that most people consider to be quite a simple creature. And...yeah. Mostly I just wanted to post mole pictures. And accompany them with penis pictures. And, well, I have accomplished that, and managed to couch it in something that resembles intelligent discourse. So I win.
Tuesday, June 9, 2009
The upshot of articles written by obsessed researchers is, naturally, that some are unintentionally hilarious (much like rabid fans of anything are unintentionally hilarious; see Trekkies). I'd make more fun, but to be honest, I was indulging my own obsession with monkey feet and their frictional mechanics when I came across this gem: "Frictional adhesion: a new angle on gecko attachment," published by Autumn et al. in the Journal of Experimental Biology (2006, vol. 209, pp 3569-3579). The study itself is pretty damned cool, as they were looking at how geckos manage to stick themselves to anything and everything without having gooey feet (like, say, frogs or insects). Geckos use dry adhesion, which they accomplish through little hair-like projections on their feet called setae, which branch into little spatulate endings. The spatulate endings contact whatever they are standing on and essentially form a bond that is amongst the best known in the natural world. They look like this:
So far, so good. I think these setae are pretty damn cool, and am most jealous that I don't have anything this cool on my toes. The unintentionally hilarious part comes once we get into the methods. Turns out that geckos are surly little bastards. "Bitey" doesn't even come close to describing their disposition. So, the researchers were left trying to find a way to get the little jerkwads to cooperate (which, in all honesty, is the main problem all animal researchers must address at some point. Do you give them a treat for good behavior or just hope and pray that they get over themselves? /snark) Did you know that "normally aggressive and temperamental" geckos become "docile when attached by a single toe to a glass surface?" I didn't either. Apparently they weren't docile enough, though, judging by the position they were attached in and the "muzzle" the researchers made for them:
Yeah. That would be sports tape holding the mouth shut. Ingenious I tell you. I'm actually considering using it on my monkeys, but they're either too smart or too dumb (depending on the day) and would either eat it, hump it and eat it, or throw it at my head. Either way, the tape would be peeled off.
And speaking of tape being peeled off; that was the main finding of the study. The detachment of gecko feet from whatever they are stuck to in no way resembles the mechanics of peeling tape. Specifically, what the study showed was that gecko setae will always detach when they are angled at least 30 degrees from the substrate they are stuck to, regardless of how heavy the gecko is. Duct tape, however, will peel faster at any angle if you apply more force to it (which, in this context, is the equivalent of having a heavier gecko). Yeah, I know, this all sounds completely inane. But it is actually pretty cool, because it means that there is something out there that has a stronger hold than duct tape, but requires less energy to peel off. This is good news for gecko researchers, who have now stumbled onto a whole new cash cow for research funding, and possibly good for 3M, provided they can patent this mechanism for sticky-notes and those hooks-that-aren't-supposed-to-kill-your-paint-job-but-do-anyway before anyone else does. Bad news for Sherwin-Williams though, although I suppose they could just launch an advertising campaign to encourage the use of nails for hanging pictures and whatnot...
So, there it is: the set-up, the punchline, and the explanation of how I am not as big of an asshole as the opening paragraphs might seem to suggest. But, this article contains and extra-special dose of fun. The authors weren't satisfied with their mathematical conclusion of how setae function (and why should they be? Math is so dull...), so they decided to apply their conclusions to a real-world model. And that, my friends, is what I shall leave you with. Ladies and gentlemen, I present to you, the "StickyBot":
*Tom assures me that geckos lick their eyeball.**
**I am too lazy to look that up, so just nod and smile, even if you know it's wrong.***
***Turns out I'm not that lazy and Tom was right. He's so amazing I still wonder why I am the one in grad school.****
****He says it's mostly because I am a masochist, but also because I have passion for learning and should stop making fun of myself.*****
*****I am putting words in his mouth and he is far too busy killing dragons online to have actually said that, but I'm sure he has said it at some point.******
******I love you Bear. You make my life worthwhile!!
I think it's fair to say that anyone who knows me well has heard me bitch about the capuchins we used to house in the lab. (Well, okay, there are probably those of you who know me well but I refrain from discussing graduate school with...mostly because I would hate to scare you...). For those of you unfamiliar with my woes, suffice it to say that capuchins are a) very smart little bastards, b) amazingly good at finding obscure parts of the wall to hang onto and jump from, and c) incredible crack-shots with monkey urine. My scalp still burns thinking about c. Their only saving grace is their cuteness. And we all know that I am a sucker for cute. And primates in general. Especially their feet. But I digress...
Anyway, it turns out that not only will capuchins pee on your head with only the slightest provocation, they're also lying, cheating little bastards. Or so says Brandon Wheeler (who I am happy to say I know...if only because he makes fun of me and screams obscenities at me from his bike on a regular basis). At Stony Brook, we like to joke about the stuffed carnivores that he used to elicit actual warning calls from the capuchins he was studying, but then again, how are you supposed to assert that they're shouting "Holy shit! BIG F'ING CAT!" if you have no idea what capuchins shout when there is a BIG F'ING CAT! present?
For those of you playing the home game, what Brandon's research found was that low ranking capuchins will often sound alarm calls for no good reason other than to scare high ranking group members away from a food source long enough for them (the low ranking member) to gank some. How do you demonstrate something like this, you may ask? How on earth are we supposed to know they're being deceptive, not being fluent in capuchin and all? Well, first you have to figure out whether the monkeys actually have specific calls for predators, or whether they are just squeaking gibberish. To do this, different models of capuchin predators were placed in the groups daily paths. When a group member gave a call, the call was recorded and the context was noted. Once it was clear that specific calls were given in the presence of certain predators (to the exclusion of just squeaking for the hell of it - there had to be a specific predator present and the call had to elicit evasive behaviors from the rest of the group), the deceptive use of these calls could be examined. As it turns out, low ranking members of capuchin groups will routinely give predator alarm calls when a limited food source is present. High ranking members get to eat first, and, as such, are usually already gorging themselves. When the alarm call is given, they freak out and run, leaving the food unguarded for the low ranking members to help themselves to.
Why on earth is this interesting? Mostly because it's comforting to know that humans are not the only primate who will lie, steal, and cheat their way through life. Lord knows we always need new excuses to justify acting like assholes. But also, because it gives us some insight into the cognitive development of other primates. It's unclear from the current research whether the monkeys lie intentionally, understanding that they are being deceptive, or if they simply associate the call with a food reward. Further research will undoubtedly focus on teasing out this difference, and either way it provides some insight into our own behavior. Is deceptiveness adaptive? Do deceptive monkeys have a higher survival rate than those who never give false alarm calls? Is this behavior genetic or learned? Are we indeed heading toward socialism, or just away from social Darwinism? Lots of important and interesting questions remain to be answered. I almost wish I was a monkey chaser rather than a gooey-jar-monkey examiner!