Okay, I admit it. I find *Man vs. Wild * utterly addictive. If I stumble across an episode I’ve never seen, I have to watch it through to the end. (Same goes for Survivorman, for those of you keeping score. Can’t we all just get along?)
Anyway, Bear eats a lot of disgusting, usually uncooked, creatures in most episodes. Most of these things I could never imagine eating myself unless I was literally in a life or death situation. I’ve got a question in case that type of situation ever arises.
Do I have to actually chew the creepycrawlies to get their full nutritional value? I think I could manage to swallow some of the (dead) worms, frogs, small snakes, fish and other soft-skinned varmints whole – hopefully followed by a gulp of water. Chewing on a live raw tree frog, OTOH, might be one act worth dying over.
Now, I’m assuming the hard-shelled critters, like all the spiders and insects, must be chewed. Is that right? Otherwise they’ll just pass through me undigested, I’m guessing.
Regarding the tree frog, he did explain that you had to kill it with your first bite; otherwise, it’d go wiggling down your throat.
Why would you think spiders and insects would pass through you undigested? Are you thinking they are encased in impenetrably welded armor? I imagine animals that normally eat these critters don’t always (if ever) take the time to chew them before swallowing.
Depends on their size, I think. Animals that are small enough might be sufficiently broken down by hydrochloric acid in the stomach so they could be fully digested in the digestive tract. In fact, anything that is the size of a normal bite of food that you would swallow will probably work. If your stomach can digest a piece of chicken skin, it should be able to digest its way through frog skin. Stuff with scales like lizards might resist digestion a bit more.
Insect and spider exoskeletons are made of chitin, which few animals can actually digest. However, hydrochloric acid again will probably break down the exoskeleton sufficiently so you can extract nutrition from the interal contents, although chewing does help:
panache45, you asked why I think that hard-shelled bugs might pass undigested? Two words: corn and peanuts.
The reason I posted this Q in the first place is that I’m not so sure that the stomach and lower digestive tract alone can do the job even if I did manage to gulp down that little headless lizard I found in my hiking boot. When I was in grammar school they taught us that digestion begins in the mouth where saliva can start breaking down the food. So again, will bypassing that step diminish my body’s ability to digest chunks of unchewed, uncooked “food”?
Humans don’t break down cellulose in the gut, so that plant parts made mostly of cellulose like the skin of a corn kernel or a peanut will pass through mainly unaffected, but the internal contents are often digested. Likewise, if you swallow insects without chewing them, you may see fairly intact bug exoskeletons in the feces but the contents will have been digested out of them through weak parts that dissolved. In fact, the scats of insectivores may consist largely of undigested bits of exoskeleton.
The only part of digestion that happens to any substantial degree in the mouth is the breakdown of starch to sugar by the enzyme amylase, found in saliva, plus the mechanical breakdown due to chewing. But even if you don’t chew, the stomach will churn and mix the food together with stomach acid, making it into a semiliquid before it enters the small intestine. You no doubt occasionally swallow relatively unchewed chunks of steak that are similar in size and digestability to a small frog. While chewing speeds the breakdown of food, it is by no means essential to digestion as long as the chunks aren’t that large to begin with.
Do all species have “hydrocloric acid” in their stomachs? Why do we have hydrocloric acid in our stomachs? Don’t get me wrong, I think that’s cool. I never had biology, as I came up when you could get out of it by taking chemisty and physics in high school.
I think (as you set cozily at your computer) you are underestimating what you would do if you were in a situation that actually required you to eat disgusting things. Exposure and hunger are persuasive motivators.
And regarding Man vs. Wild, give me that job and that paycheck and I’ll gladly munch spiders down.
As far as I know secretion of hydrochloric acid is pretty general among vertebrates, but offhand I don’t know if it is also found in invertebrates. We have it because it’s pretty damn good for breaking stuff down into its components. Of course, such a powerful acid presents problems because it can start digesting the stomach lining itself and produce ulcers. The stomach’s mucus lining generally prevents this.