# Why are cats' tongues designed like that?
**URL:** https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326
**Category:** Factual Questions
**Created:** [July 9, 2004, 6:38pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326 "2004-07-09T18:38:52Z")
**Posts on this page:** 16
**Page:** 2
### Author:  [@overlyverbose](https://boards.straightdope.com/u/overlyverbose)
#### Post date: [July 10, 2004, 2:48am UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/21 "2004-07-10T02:48:30Z")
I was watching a documentary on lions once that said that cats groom themselves so often because they need to be sure to completely wash the blood of a kill of their fur. If they don’t, their prey can smell them, and will be frightened off by the scent of blood. So I suppose that the ability to cough up hairballs is somewhat useful after all - they clean all the blood off, and any hair that gets caught in their digestive tract in the process is regurgitated. I suppose that domestic cats may groom themselves so much as a holdover to when they were wild, and closer to the African Wild Cat, their nearest ancestor. Evolutionarily speaking, 5,000 years isn’t all that long, so it wouldn’t be unreasonable to assume that domestic cats have a lot of unnecessary, perhaps residual, behavior and physical traits in common with their wild cousins.
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### Author:  [@BoringDad](https://boards.straightdope.com/u/BoringDad)
#### Post date: [July 10, 2004, 2:57pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/22 "2004-07-10T14:57:12Z")
> [@RitzyRae](#):
>
> And it also seems that our **long haired** kitty, who grooms everyone else as well as herself, does have hairballs more frequently than others. But…
Well there is your answer right there **RitzyRae**. Long haired cats would likely not have survived in the wild. Hair balls are not nearly as big a problem for short haired cats.
And once again, a nitpick…
> [@overlyverbose](#):
>
> I was watching a documentary on lions once that said that cats groom themselves so often because they need to be sure to completely wash the blood of a kill of their fur.
If the claim was made that cats are smart enough to consciously think “Hey, I better clean the scent off me so that my next prey can’t smell me.” then this documentary may have been true. Otherwise, what is really the case is that the cats where the self cleaning behavior popped up were the ones that survived. Possibly they survived because the cleaning behavior allowed them to sneak up on prey better, or they smelled better to potential mates, or maybe the fur cleaning had nothing to do with their enhanced survival except as a secondary characteristic of the behavor of licking wounds to keep them clean. Or heck, maybe it just feels really good? Evolution does not intentionally give animals behaviors to allow them to survive.
Maybe someday maybe I’ll see a documentary that says “The cats that groom themselves often have been the only cats that survived. Scientists speculate that the enhanced survival of grooming cats is due to the following factors…”
Forgive the continued nitpcking of phrasing, but the “smart evolution” that is stuck in people’s minds is the most powerful weapon that Creationists have to use against science.
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### Author:  [@vetbridge](https://boards.straightdope.com/u/vetbridge)
#### Post date: [July 10, 2004, 3:49pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/23 "2004-07-10T15:49:57Z")
> [@RitzyRae](#):
>
> it still seems like their inability to digest hair is a rather significant design flaw.
Part of the problem is that diets formulated for house cats are low in fiber compared to a cat feeding on fresh kills. Increasing the fiber content will help move hair through the gastrointestinal tract, however it will also cause a bulky stool.
Hills (makers of Science Diet) offer a “hairball diet” with added fiber.
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### Author:  [@overlyverbose](https://boards.straightdope.com/u/overlyverbose)
#### Post date: [July 10, 2004, 4:05pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/24 "2004-07-10T16:05:46Z")
> [@BoringDad](#):
>
> Forgive the continued nitpcking of phrasing, but the “smart evolution” that is stuck in people’s minds is the most powerful weapon that Creationists have to use against science.
ARGH!! This is driving me nuts! Although I may have phrased it in a somewhat simplistic manner, I do not feel that I ever implied that cats made a conscious effort to lick themselves because they thought about it for a while and _knew_, after careful reasoning, they’d need to wash the kill off. You’re right - Darwinian evolution would indicate that cats licking themselves clean of the scent of prey would _happen_ to be the ones to get the food, hence would _happen_ to live to reproduce and pass those traits on to their offspring. I guess I sort of assumed that, because of the intelligent nature of most people who post to this board, everyone here _knew_ that cats couldn’t think at such an intelligent level, and that evolution does not work that way.
I’m very frustrated because I feel as though you are taking my words (and the OP’s words) out of context here. As a former archaeologist, my colleagues and I rarely took the time to say to each other, “Well, I _know_ that they didn’t do it on purpose - it was evolution, you see, which is really a blind process and not controlled by thought, particularly in animals, but it so happens that…” It seems so unnecessary and redundant when you’re talking about science, particularly here where I have yet to see anyone assert that cats sat around pondering the best behavior to ensure their continued existence.
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### Author:  [@Lynn\_Bodoni](https://boards.straightdope.com/u/Lynn_Bodoni)
#### Post date: [July 10, 2004, 4:12pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/25 "2004-07-10T16:12:22Z")
> [@overlyverbose](#):
>
> I think hairballs depend upon the individual cat. Some cough 'em up more than others, regardless of the length (or lack thereof) of hair. My cats are both longhair/shorthair mixes. I think. I’m not really sure, 'cause I got them from the pound, and they weren’t sure what they were, but both cats have hair that’s a little too long to be shorthaired, and way too short to be longhaired. If that makes any sense. Anyway, they both groom a lot, even groom each other, but neither has problems with hairballs. I think they get them once every two or three months or so. Of course, now that I’ve said that I’ll probably step in one as soon as I leave my office. Yuck.
I’ve seen references to “semi-longhaired” cats. Probably your cats fall into this category. I’ve seen the fur length that you’re talking about…nowhere near as long as a Persian’s, but definitely longer than the average short-haired cat.
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### Author:  [@overlyverbose](https://boards.straightdope.com/u/overlyverbose)
#### Post date: [July 10, 2004, 4:46pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/26 "2004-07-10T16:46:33Z")
> [@Lynn Bodoni](#):
>
> I’ve seen references to “semi-longhaired” cats. Probably your cats fall into this category. I’ve seen the fur length that you’re talking about…nowhere near as long as a Persian’s, but definitely longer than the average short-haired cat.
Yeah, I think they both do. One of them is part-Siamese, too, so her hair is ever so slightly longer than my other “semi-longhaired” cat.
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### Author:  [@BoringDad](https://boards.straightdope.com/u/BoringDad)
#### Post date: [July 10, 2004, 6:17pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/27 "2004-07-10T18:17:53Z")
> [@overlyverbose](#):
>
> ARGH!! This is driving me nuts!
>
> I’m very frustrated because I feel as though you are taking my words (and the OP’s words) out of context here. As a former archaeologist, my colleagues and I rarely took the time to say to each other, “Well, I _know_ that they didn’t do it on purpose - it was evolution, you see, which is really a blind process and not controlled by thought, particularly in animals, but it so happens that…” It seems so unnecessary and redundant when you’re talking about science, particularly here where I have yet to see anyone assert that cats sat around pondering the best behavior to ensure their continued existence.
I could have phrased it better. I did not mean to imply anyone was saying that cats thought about it. What I was trying to say was that the documentary you referenced
> [@](#):
>
> a documentary on lions once that said that cats groom themselves so often because they need to be sure to completely wash the blood of a kill of their fur
seemed to indicate that there was a specific purpose to the cat’s behavior. I was being perhaps impolitely snarky when I tried to say that the only way the documentary could have been right in this phrasing is if the cats did make a decision, and since we know that is not the case, then we know that the documentary gave a misleading impression.
And when you are around scientists, then yes, there would be no reason to pick on this point. But the level of misunderstanding of evolution amongst even quite intelligent people is staggering. So I take it upon myself to be a self imposed very annoying evolution cop. I just can’t help it. And the OP specifically rung a bell with the question about “design” of a cat. To imply that evolution designed cats is what leads many people astray.
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### Author:  [@Spectre\_of\_Pithecanthropus](https://boards.straightdope.com/u/Spectre_of_Pithecanthropus)
#### Post date: [July 10, 2004, 8:34pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/28 "2004-07-10T20:34:26Z")
> [@overlyverbose](#):
>
> I was watching a documentary on lions once that said that cats groom themselves so often because they need to be sure to completely wash the blood of a kill of their fur.
I’ve noticed that every housecat I’ve ever seen washes its front paws and face after eating, even it it was just a can of Whiskas Ground Mealtime. I always did think it was a holdover from the need to wash off the blood after eating prey.
> [@](#):
>
> unnecessary, perhaps residual, behavior and physical traits in common with their wild cousins.
Unnecessary and residual? Definitely not for all housecats. If you don’t believe me, just google “Feline predation” and “songbirds”. There are pages and pages of material on how cats who are allowed to roam outdoors affect the bird population. Not to mention other prey such as rodents, which are more natural for small cats.
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### Author:  [@Darwins\_Finch](https://boards.straightdope.com/u/Darwins_Finch)
#### Post date: [July 10, 2004, 10:07pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/29 "2004-07-10T22:07:17Z")
> [@BoringDad](#):
>
> And when you are around scientists, then yes, there would be no reason to pick on this point. But the level of misunderstanding of evolution amongst even quite intelligent people is staggering. So I take it upon myself to be a self imposed very annoying evolution cop.
Then you might want to pick your fights. There’s a big difference between comments about intelligently-guided evolution and the selective pressures which, _do_, in fact, direct evolution. The documentary comment was indicative of the latter, not the former. Perhaps the documentary in question _could_ have stated that “selective pressures were such that those felines which engaged in self-cleaning behavior had greater success during the hunt, and such a behavior in turn tended to impart differential reproduction favoring those individuals, and thereby increased the relative frequency of that particular trait within feline populations”, but I think most folks would probably have fallen asleep halfway through that sentence. Heck, some readers here probably just did. Thus, the shorthand version of saying the same thing: “the _reason_ for the behavior is…”. It does not imply that it is the result of conscious choice, either on the part of the cat or of nature or evolution in general. It’s simply a statement about the underlying pressures which favored the selection of the trait.
Granted, often such reasons are difficult to pin down and are, as a result, largely speculative (a particualr problem in human paleontology and some areas of anthropology, I might add…), but they are, for the most part, also falsifiable statements. If it is shown that felines which don’t clean themselves do not hunt well, and are thus less likely to reproduce, while those cats which do clean themsleves get the kills and the lady cats, then it is not necessarily incorrect to say, “cats clean themsleves in order to aid in hunting”. If the opposite is found to be the case, or if no correlation between cleanliness and hunting success or reproduction were found, then it would be an incorrect statement.
Hey, I’ve been plenty nitpicky about evolutionary details (look up any recent thread which mentions dinosaur extinction, for example, or threads about natural selection - I don’t know how many times I have to intervene and mention that NS is more than just culling the weak!), so I understand where you’re coming from. But militants don’t win converts. One can be informative without being annoying.
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### Author:  [@USCDiver](https://boards.straightdope.com/u/USCDiver)
#### Post date: [July 10, 2004, 10:13pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/30 "2004-07-10T22:13:32Z")
> [@vetbridge](#):
>
> Part of the problem is that diets formulated for house cats are low in fiber compared to a cat feeding on fresh kills. Increasing the fiber content will help move hair through the gastrointestinal tract, however it will also cause a bulky stool.
>
> Hills (makers of Science Diet) offer a “hairball diet” with added fiber.
I assume from your user name you’re involved in the veterinarian field, but can you explain how a diet of ‘fresh kills,’ essentially all meat, is high in fiber?
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### Author:  [@1010011010](https://boards.straightdope.com/u/1010011010)
#### Post date: [July 10, 2004, 10:23pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/31 "2004-07-10T22:23:57Z")
> [@USCDiver](#):
>
> I assume from your user name you’re involved in the veterinarian field, but can you explain how a diet of ‘fresh kills,’ essentially all meat, is high in fiber?
Wild animals generally don’t gut their prey, thus whatever the prey’s last meal happened to be ends up getting eaten as well.
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### Author:  [@overlyverbose](https://boards.straightdope.com/u/overlyverbose)
#### Post date: [July 10, 2004, 10:30pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/32 "2004-07-10T22:30:48Z")
> [@USCDiver](#):
>
> I assume from your user name you’re involved in the veterinarian field, but can you explain how a diet of ‘fresh kills,’ essentially all meat, is high in fiber?
Oooh! Ooh! Me! I know the answer to this one, too! 😃
I know your question wasn’t directed at me, but if you don’t mind, I’ll answer anyway. Most cats, particularly wild cats, eat some plants. Scientists aren’t quite sure why they do it - most wild cats are able to get their fiber through the contents of their prey’s intestines (in fact, it’s probably easier for cats to do it this way because the fiber has been turned into a more digestible form for the cat - I’ve been told that cats don’t really have the chemical equipment to digest plants well, so it’s easier if they get it pre-digested); however, scientists speculate that feline plant-eating might supplement meager fiber intake. Getting more fiber would result in fewer problems passing hairballs, or it might help the cat barf the hairballs right up, providing immediate relief for any indigestion. Or cats might do it because the plant tastes good or because it has pleasurable effects like catnip.
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### Author:  [@StarvingButStrong](https://boards.straightdope.com/u/StarvingButStrong)
#### Post date: [July 11, 2004, 3:03am UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/33 "2004-07-11T03:03:09Z")
About the roughage: long ago we had a cat who was an absolute terror at catching birds. He would crouch down near trees or bird feeders and wait for some poor bird to fly by too low, at which point SPROING!! with a magnificent leap and a mouthful of bird almost always resulting.
Once the bird was caught, and thoroughly dead, he would bring it back to our house, come in through the pet door, travel down the hall to the laundry room, and deposit dinner into his food dish as nicely as you could please. This always freaked out our mother, so she would close the door to the laundry room to keep the cat from making a mess or hiding parts of it elsewhere.
The thing is, when we’d open the door an hour or two later, we would find a contented cat and MAYBE a stray feather or two. Mostly not even that: the cat ate the entire bird, beak to toes to tip of tail, all bones and guts and feathers. Feathers at least gotta count as roughage, right? I mean, if the cat could digest feathers, it could digest its own hair, I’d think, since they’re made from similar molecules.
BTW, as for vomiting up the hairballs being a detriment to the cat in evolutionary terms, either by causing distress or loss of food: nope. Have you ever seen a cat vomit? They can upchuck as quickly and easily as they swallow. And if they DO happen to vomit shortly after a meal, meaning a lot of food coming out, the little darlings won’t hesitate to re-eat the food.
(You really wanted to know that, right?)
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### Author:  [@BoringDad](https://boards.straightdope.com/u/BoringDad)
#### Post date: [July 11, 2004, 3:55pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/34 "2004-07-11T15:55:19Z")
> [@Darwin's Finch](#):
>
> Perhaps the documentary in question _could_ have stated that “selective pressures were such that those felines which engaged in self-cleaning behavior had greater success during the hunt, and such a behavior in turn tended to impart differential reproduction favoring those individuals, and thereby increased the relative frequency of that particular trait within feline populations”, but I think most folks would probably have fallen asleep halfway through that sentence. Heck, some readers here probably just did. Thus, the shorthand version of saying the same thing: “the _reason_ for the behavior is…”.
Or it could have simply said “The cleaning behavor aids in many things, one of which is reducing smell of prey animals on it’s fur.” Thereby not being boring and also indicating that the cleaning behavior, while aiding hunting, is not done specifically in order to aid hunting.
> [@](#):
>
> But militants don’t win converts. One can be informative without being annoying.
I was not trying to win converts, (and really, can you call it a “converting” when it is just educating them about the science?) but to prevent the dissemination of impressions that give people a skewed idea of evolution. And, sadly, while one may be able to do this without being annoying… I cannot. My friends would all agree that being annoying and unable to stop myself even when I know I’m being annoying is one of my many flawed personality traits. However, I do appreciate corrections if I get my facts wrong (my scientific background is not evolution).
To summarize, I am sorry for being picky and annoying, but am unlikely to stop being either.
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### Author:  [@BoringDad](https://boards.straightdope.com/u/BoringDad)
#### Post date: [July 11, 2004, 4:00pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/35 "2004-07-11T16:00:04Z")
> [@overlyverbose](#):
>
> Oooh! Ooh! Me! I know the answer to this one, too! 😃
>
> I know your question wasn’t directed at me, but if you don’t mind, I’ll answer anyway. Most cats, particularly wild cats, eat some plants. Scientists aren’t quite sure why they do it - most wild cats are able to get their fiber through the contents of their prey’s intestines (in fact, it’s probably easier for cats to do it this way because the fiber has been turned into a more digestible form for the cat - I’ve been told that cats don’t really have the chemical equipment to digest plants well, so it’s easier if they get it pre-digested);
Cool! I never knew that. So if eating the gut and contents of the prey give the cat more fiber, I wonder what my cat gets out of eating the head first?
> [@StarvingButStrong](#):
>
> Feathers at least gotta count as roughage, right? I mean, if the cat could digest feathers, it could digest its own hair, I’d think, since they’re made from similar molecules.
The feathers my cat eats either are puked out later, or pass through relatively undigested. I would guess that the feathers are easier to pass since they won’t knot up like hair?
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### Author:  [@overlyverbose](https://boards.straightdope.com/u/overlyverbose)
#### Post date: [July 11, 2004, 5:10pm UTC](https://boards.straightdope.com/t/why-are-cats-tongues-designed-like-that/254326/36 "2004-07-11T17:10:13Z")
> [@BoringDad](#):
>
> To summarize, I am sorry for being picky and annoying, but am unlikely to stop being either.
Hey, I still like you. 🙂
So, your cat eats the head first? Impressive. Whenever my cats find something to kill, they usually just play with it until it’s dead, then deposit it at my feet. Which is quite considerate of them if they’re trying to feed me; however, I still hate it, because they usually find these abnormally long centipede-like things. I’d far prefer a headless bird or mouse - anything with more than 6-8 legs really freaks me out.
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