Why will dogs eat these things?

July 19, 2009 5:25 PM

Given their acute senses, why do dogs eat gross things?

If smell and taste are related, and dogs have excellent senses of smell, then it would make sense to me that they would have acute senses of taste. Like, stronger taste buds than humans. Why, then, do they eat things that I can't imagine would taste good? My dogs really enjoy eating and/ or chewing things like stinky shoes, bark and cat poo (we keep them from it, but if we forget to close the door it's the first thing they go for). I would think one would only want to eat those if they had NO sense of smell/ taste. How can these things taste good to them?

posted by roxie5 to Pets & Animals (27 answers total)

Other people will eat things/wear scents that I find horrendous. I'm no surprised in the least that animals have different tastes from humans in what kind of scents/flavors they like.
posted by HFSH at 5:29 PM on July 19, 2009

Why do dogs bark rather than speak? They're a different species, and comparisons with humans are kind of futile. You're only imagining that cat poo doesn't taste good, you've probably never tried it and I presume you've never been a hungry dog. That said, humans are programmed to reject and fear things that will cause them harm or make them ill; spiders, out of date food, excrement, scorpions, etc - dogs don't operate with such sophistication. On a basic level cat shit probably tastes good because it contains cat food.
posted by fire&wings at 5:35 PM on July 19, 2009 [1 favorite]

Well, dogs do "reject and fear things that will cause them harm or make them ill" such as rotting flesh.

But they may not understand that cat shit is digested matter, just like babies don't understand that their feces ought not be played with.
posted by dfriedman at 5:37 PM on July 19, 2009

They are hungry.
posted by caddis at 5:37 PM on July 19, 2009

They don't eat gross things. They eat things that are gross to humans. They do this because they are not humans.
posted by Flunkie at 5:38 PM on July 19, 2009 [11 favorites]

Dogs are scavengers as well as hunters and will eat anything that might give them a small cushion against starvation. Cat shit, which is nothing more than gently used cat food, might give them such a cushion.

Our instincts tell us to avoid eating things that smell rotting or infectious. Dogs' instincts tell them to eat whatever seems even remotely edible because it might be all they get for a very long time.
posted by balls at 5:43 PM on July 19, 2009 [9 favorites]

A dog's taste isn't heightened like its smell is. They have, according to one source at least, 1/6th the number of taste buds we do. Maybe that explains some of their indifference?
posted by tybeet at 5:48 PM on July 19, 2009

Obviously, they can detect the hidden and subtle deliciousness of the chicken-juice diaper pads that have been left in the garbage for two days. Their finely tuned sense of smell lets them know when it's ripe.
posted by Jon-o at 5:51 PM on July 19, 2009 [2 favorites]

Easting (and rolling around in) smelly stuffy also hides their own smell from other animals with excellent senses of smell.
posted by Etaoin Shrdlu at 6:13 PM on July 19, 2009

I read somewhere (sorry, can't remember or I'd gladly cite) that dogs basically categorize all smells into "interesting" or "bad." A dog's idea of "bad" has very little overlap with what humans would consider offensive. Whatever is left (e.g. 'interesting') is fair game for tasting, eating, and rolling around in.
posted by contessa at 6:15 PM on July 19, 2009

Smelly stuff like feces and butts can impart a tremendous amount of information with a more nuanced sense of smell than what we have. Animals eat feces specifically in part because it lets them consume nutrients that might have passed through the first time. I've always assumed that a dog's penchant for eating "gross" stuff has to do with one or the other of these facts.
posted by PhoBWanKenobi at 6:19 PM on July 19, 2009

According to an article I read a year or so ago in The Bark, it can also be a learned behavior from their mothers. If they are born in an area that isn't kept clean (i.e., the whelping takes place in the wild or it's neglected by the breeder) then the mother will often eat the feces of the puppies to keep the area clean.
posted by Ufez Jones at 6:28 PM on July 19, 2009

One thing is that dogs can and do puke up anything that their stomach takes the remotest exception to.

So if a bunch of cat poo smells like a protein-rich treat (and it is, cats have inefficient digestions) then the dog can hoover it up, and if there's anything their stomach can't handle, up it comes again, no harm done.

Cf other carrion eaters like hyaenas and vultures. Great pukers all.
posted by i_am_joe's_spleen at 7:33 PM on July 19, 2009 [3 favorites]

I'm with Ufez - it's about cleaning up. My cat (yes, totally different species, but still...) will grab my hand after I've wiped goop out of her eyes or ears so that she can lick it off my finger/washcloth. I don't for a second believe that cat ear wax tastes good, but I totally believe it'd be a strong instinct. If the dog thinks poop tastes terrible, how will it ever keep its butt clean?
posted by aimedwander at 7:44 PM on July 19, 2009

I imagine dogs wonder the same thing about blue cheese, boogers and earwax.
posted by flabdablet at 8:18 PM on July 19, 2009

I heard from friends once that the reason dogs like to eat human shit is that human shit is only partially digested, and tastes like yummy food to a dog.

Plus, as visiting some exotic locales have demonstrated to me, "gross" is a largely cultural designation, not so much a biological one.
posted by telstar at 8:33 PM on July 19, 2009

I've always thought that the broadened sense of taste and smell that dogs have means that there's just a whole new world there, just like the sensitivity and richness of our sense of sight means that we can immerse ourselves in things like movies and television shows.

So for a dog, eating rat feces is like how watching a bad movie would be for us; yeah, it's bad, but at least it's something interesting to experience, and there's just enough sensation to it that we can put the fact that it's actually really bad out of our minds.
posted by koeselitz at 8:56 PM on July 19, 2009 [1 favorite]

No clue about cat (or dog) digestive tracts, but there are some bacteria in the lower part of the human gut that synthesize vitamin K, too far along for people to absorb it as it's being produced. Draw what conclusions you will about the fussiness and/or cleanliness of our evolutionary forebears.

Further, the volatile component that smells literally like shit, skatole, is complicated an interesting. It's pleasant to the human nose in very low concentrations (see the wikipedia article), so who's to say that dogs don't register it as lovely? Furthermore, its indole chemical structure is clearly a derivative of and in lower organisms is a component of trypophan synthesis. No clue if dogs are able to synthesize that amino acid, probably not, but maybe their gut flora do? Weirder things have happened.
posted by Sublimity at 9:14 PM on July 19, 2009

While dogs may have acute senses, the don't have acute squeamishness.
posted by ActingTheGoat at 11:18 PM on July 19, 2009 [1 favorite]

A similar question was posed by my girlfriend the other day: if dogs have such a great sense of smell, how come their own farts don't make them gag? I have to guess, along with others, that it's an adaptation in favour of not passing up food. Presumably, for most of the time that dogs have had their evolution shaped by their relationship with humans, they have been fed leftover that the humans didn't want to eat - gross by definition.
posted by primer_dimer at 2:22 AM on July 20, 2009

This has puzzled me, too, for quite some time.

I have a beagle, Spawn of Satan, (my wife, however calls it Tippy). Her screening criteria is whether or not a substance contains any carbon molecules. If so, fair game.

If I died during dinner, the dog would be there to first consume whatever I left uneaten, then would start on me.

I loan her my own squeamishness by preventing her from sucking up cat puke as it is being produced (much to the chagrin of my cat) and shield her from kitty litter constipation by locating it in an inaccessible recess.

I swear this dog would eat a concrete sculpture of food. WTF?
posted by FauxScot at 3:18 AM on July 20, 2009 [2 favorites]

Which is weird, because there aren't a lot of carbon molecules in concrete.
posted by flabdablet at 3:51 AM on July 20, 2009 [2 favorites]

LOL FauxScot, my half-beagle has much the same appetite. Never, ever, will that dog appear to be full or refuse food.

She even likes the fireplace pebbles and volcanic grill rocks (but those have yummy meat juice on them).

We've tried a couple of deterrents that she ends up liking: bitter apple keepaway sauce and hot sauce.
posted by toastchee at 5:21 AM on July 20, 2009

We left the Laundry room door open one afternoon and our Male Beagle gorged himself on Cat poop until he was physically ill from eating so much..then he threw it up. I still have nightmares about the clean up.
.....

The short version is, if you can swallow it, digest it, extract some nutrients from it, and not die, then it is food. Hell, actually digesting it and getting some nutritional value are optional as well. Dogs just have fewer hangups
posted by Lord Widebottom at 6:45 AM on July 20, 2009

Great question; I've wondered about this for a long time, too, particularly the excrement eating.

Reading this thread, it occurs to me that it might be an instinct-driven part of a hunting strategy.

If a dog or a pack of dogs is pursuing some prey animal, it could be very advantageous to have a mouth full of pathogenic bacteria. If a dog with a filthy mouth manages to run in and break the skin, say on the leg of the prey, then a day or two later after the infection sets in, that animal is not going to be able to keep up with the herd or effectively run away, or even competently do the kind of spinning and kicking hoofed animals do to stave off attacks, and becomes easy meat.

Lions do something weird that could be seen as a parallel, perhaps. When a pride brings down an animal, it typically shits itself in extremis, and the rest of the pride has been observed to immediately defer to the dominant male, who then proceeds to consume the besmeared hindquarters with evident relish.

Some hunters and gatherers have smeared their spear points with offal for the express purpose of causing infected wounds, apparently.

Maybe cats are scratching around in the litter box to turn their claws into bioweapons, as well.
posted by jamjam at 10:14 AM on July 20, 2009

Here is the excellent (and graphic!) Nathan Myhrvold photo essay on lions from which I learned about their excrement eating proclivities:

Lions don't wait to kill the animal before starting the process of eating it—as soon as the buffalo stops thrashing, lions start to eat. This is much harder than it sounds however, because the hide is very thick. The prime spot to start is always claimed by the dominant female, or if the male is there, he takes the prime spot. The prime spot is not what you might thing—it is the rectum. Believe it or not, the king of beasts starts his dinner by carefully licking the rectum clean. Since the buffalo defecates while dying this is a bit messy. The lion then works very hard to gnaw through the skin and get an incision open.
posted by jamjam at 12:10 PM on July 20, 2009

Wild dog mothers keep the dens clean by eating the feces of their pups, until they are old enough to be "den-trained". This keeps down the smell (since the pups are vulnerable to predators whenever mom is out), and of course the hygiene of the den.

By extension, I've noticed large, domesticated dogs will happily eat the poop of virtually any housemember (cat, puppy, baby human) that is smaller than them. An ex-girlfriend had a toy chihuahua; he had no interest in the litter box of the relatively larger cats at all.

FWIW, I suspect the poop-eating is a mothering instinct.
posted by IAmBroom at 12:22 PM on July 20, 2009