PDA

View Full Version : About carnivores


chowder
04-06-2009, 06:25 AM
As I understand we humans cannot live on a diet of protein alone and I'm assuming that carnivores such as Lions, Tigers, wolves etc are just the same.

So where do these animals get the other foodstuffs from to enable to live?

Chief Pedant
04-06-2009, 07:10 AM
As I understand we humans cannot live on a diet of protein alone and I'm assuming that carnivores such as Lions, Tigers, wolves etc are just the same.

So where do these animals get the other foodstuffs from to enable to live?

Carnivores are taking in blood, fat, bone and meat, along with various organs--a lot more than just "protein" if by "protein" you mean amino acids.

Is your question around trace elements or the need for veggies? Your mom was exaggerating a little when she said you had to eat your veggies. They are good for you, but not absolutely necessary. NB carnivores tend not to live particularly long lives, although on this Board someone will come along shortly and correct me with some exception or another, I'm sure.

twickster
04-06-2009, 07:31 AM
Plus, not all "carnivores" are exclusively meat-eaters -- though the main part of their diet may come from meat, many will not turn up their noses at plant materials that present themselves (e.g., house cats eating grass).

Staggerlee
04-06-2009, 07:52 AM
I asked a similar question some time ago on here - as to how animals aren't constantly malnourished with their monotonous diets. Turned out that the animals in question can synthesise all the right vitamins and things from their samey food intake - although only humans and guinea pigs have lost the ability to synthesise Vitamin C, so need to take it in their diet.

Moral: never take your guinea pig on a long sea voyage.

Shodan
04-06-2009, 07:57 AM
I believe many carnivores will also eat the contents of the digestive tract, so they are getting some semi-digested carbohydrates as well.

Regards,
Shodan

HorseloverFat
04-06-2009, 09:10 AM
Eating a liver is like eating a giant multivitamin. Eating bones is like a hot injection of calcium. Unlike modern human dining, animals tend to eat organs as well as meat. Toss in natural synthesis of vitamins and Mr. Carnivore is doing alright.

chowder
04-06-2009, 09:49 AM
Plus, not all "carnivores" are exclusively meat-eaters -- though the main part of their diet may come from meat, many will not turn up their noses at plant materials that present themselves (e.g., house cats eating grass).

House cats eat grass as an emetic not as a food.

Pleonast
04-06-2009, 10:01 AM
I asked a similar question some time ago on here - as to how animals aren't constantly malnourished with their monotonous diets. Turned out that the animals in question can synthesise all the right vitamins and things from their samey food intake - although only humans and guinea pigs have lost the ability to synthesise Vitamin C, so need to take it in their diet.You're mostly right--most primates cannot synthesize their own vitamin C, so humans aren't really special.

Lemur866
04-06-2009, 10:04 AM
...although only humans and guinea pigs have lost the ability to synthesise Vitamin C, so need to take it in their diet.

Not just humans but all primates have lost the ability to synthesize vitamin C.

Different animals have different nutritional needs. A cow can get everything it needs to live simply by eating grass because its digestive system is organized differently than the human digestive system.

DrDeth
04-06-2009, 11:17 AM
As I understand we humans cannot live on a diet of protein alone and I'm assuming that carnivores such as Lions, Tigers, wolves etc are just the same.

So where do these animals get the other foodstuffs from to enable to live?

You don't need to injest carbs. Your body can metabolize Protiens to get the needed glucose. You do need a small amount of fat.

Here's what you need (in rough order):

A source of energy (Fats, protiens, carbs)
Protiens, well balanced (which meat does)
Fiber (pretty much veg sources only)
Essential fatty acids (EFA) and fats. (Meat has these)
minerals. (Meat is a good source)
vitamins. (In raw or rare fresh meat you can get pretty much any vitamin, vit C has to be watched)
trace nutrients. (phytos, anti-oxidants, etc, mostly in bright and dark colored veggies)

And fiber is the one thing that even total carnivores like cats eat grass for.

As has been said, carnivores tend to eat organ meats etc, also, not just muscle tissue.

chowder
04-06-2009, 11:22 AM
DrDeth

My understanding is that cats only eat grass as an emetic, to make them sick in order to get rid of fur balls.

I may be wrong of course, if I am, someone will put me right

If I'm right, where do carnivores get their fibre from?

DSYoungEsq
04-06-2009, 11:23 AM
Many of the questions asked in the OP are answered in this thread about cats as carnivores (http://boards.straightdope.com/sdmb/showthread.php?t=512700), going on simulaneously. :)

DrDeth
04-06-2009, 11:42 AM
DrDeth

My understanding is that cats only eat grass as an emetic, to make them sick in order to get rid of fur balls.

I may be wrong of course, if I am, someone will put me right

If I'm right, where do carnivores get their fibre from?

That is indeed one use of grass. But if you have had cats and allow them access to cat grass, you will see cat scat with grass in it in the litter box. Cats and other carnivores also get grass, ect when they consume the stomach contents.

Here's an article about cats & grass which shows coughing up fur balls to the the secondary benefit.


http://www.pet-food-zone.com/cat_eating_grass.htm

chowder
04-06-2009, 11:45 AM
That is indeed one use of grass. But if you have had cats and allow them access to cat grass, you will see cat scat with grass in it in the litter box. Cats and other carnivores also get grass, ect when they consume the stomach contents.

Here's an article about cats & grass which shows coughing up fur balls to the the secondary benefit.


http://www.pet-food-zone.com/cat_eating_grass.htm

Well I'll be jiggered:smack:

I've had cats for many years, matter of fact my last one died just a few days ago.

I never knew they ate grass for anything other than coughing up fur balls

Lemur866
04-06-2009, 12:54 PM
DrDeth

My understanding is that cats only eat grass as an emetic, to make them sick in order to get rid of fur balls.

I may be wrong of course, if I am, someone will put me right

If I'm right, where do carnivores get their fibre from?

They just don't need the same amount of fiber that humans need. A healthy diet for a human would kill a cow or a horse. We need fiber because our digestive systems evolved to deal with a diet that has a moderate amount of fiber, and if our digestive systems don't get what they evolved to deal with they don't work well. A cow's digestive system presupposes massive amounts of cellulose, if they don't get it they will die. A cat's digestive system evolved to deal with almost no fiber, so they don't need it to stay healthy.

Jophiel
04-06-2009, 01:13 PM
Moving away from mammals, there's a bit in The Life of Birds (http://www.imdb.com/title/tt0175394/) in which David Attenborough remarks that meat is so packed with nutritional goodness that a single successful kill will sustain (some raptor or another) for a full day of flying around and doing bird stuff. This was in marked contrast to the herbivore birds who'd spend all day trying to locate enough seeds, berries, etc.

So I guess you just need the system to extract all the meaty goodness. I'm fairly sure raptors don't supplement their diet with fruits & nuts.

yabob
04-06-2009, 01:27 PM
If you really want a specialized digestive system in a mammal, consider the vampire bat, which lives on blood. I doubt that very many other animals could get away with that diet.

ETA:

At least not warm-blooded vertebrate animals. Plenty of worms, etc, do OK that way.

chowder
04-06-2009, 01:43 PM
If you really want a specialized digestive system in a mammal, consider the vampire bat, which lives on blood. I doubt that very many other animals could get away with that diet.

ETA:

At least not warm-blooded vertebrate animals. Plenty of worms, etc, do OK that way.

Have you seen a vampire bat?

I just Googled, jebus they are ugly buggers for sure

DrDeth
04-06-2009, 02:40 PM
To add something here- for those of you with an indoor only cat(s)*, please make sure he has a little grass to graze on. Specialized "kitty-grass" from the pet store is OK, but a tad over-priced, you can just buy the same sized tub of wheat-grass at your grocery store. Or grow your own, using oat seeds.


* and of course, in general, most cats should be indoor only in todays world. ymmv.

Umbriel2
04-06-2009, 02:45 PM
Conversely, nominal herbivores get some measure of protein from insects and other small animal life (like ground nesting birds) that they consume while grazing.

Stranger On A Train
04-06-2009, 04:53 PM
You don't need to injest carbs. Your body can metabolize Protiens to get the needed glucose. You do need a small amount of fat.Humans can only synthesize a small amount of glucose from proteins via gluconeogenesis, and at the cost of the production of ketones which increases blood acidity and stresses the liver and kidneys. You couldn't live on pure protein and lipids, and you most certainly do need to consume carbohydrates. However, vertebrate muscle tissue is at most 30% protein, and some types of organ meats are upwards of 60% carbohydrates. Most members of order Carnivora are not strict carnivores; the few that are are apex predators which do not engage in extended aerobic pursuit but instead rely on stealth and stalking predation to achieve kills, limiting the need for raw carbohydrate consumption.

Stranger

DrDeth
04-08-2009, 12:41 PM
Humans can only synthesize a small amount of glucose from proteins via gluconeogenesis, and at the cost of the production of ketones which increases blood acidity and stresses the liver and kidneys. You couldn't live on pure protein and lipids, and you most certainly do need to consume carbohydrates. However, vertebrate muscle tissue is at most 30% protein, and some types of organ meats are upwards of 60% carbohydrates. Most members of order Carnivora are not strict carnivores; the few that are are apex predators which do not engage in extended aerobic pursuit but instead rely on stealth and stalking predation to achieve kills, limiting the need for raw carbohydrate consumption.

Stranger

Well, the Master disagrees, one can exist safely on a all-meat diet:


http://www.straightdope.com/columns/read/2374/traditionally-eskimos-ate-only-meat-and-fish-why-didnt-they-get-scurvy

Most meat contains 0 carbs. It's true, as you say that meat isn't all proteins, it does contain a significant amount of water, and of course fat. Some does contain a tiny amount of carbs.

http://en.wikipedia.org/wiki/Meat#Main_constituents

"Adult mammalian muscle flesh consists of roughly 75 percent of water, 19 percent of protein, 2.5 percent of intramuscular fat, 1.2 percent of carbohydrates and 2.3 percent of other soluble non-protein substances. These include nitrogenous compounds, such as amino acids, and inorganic substances such as minerals.[35]

Quercus
04-08-2009, 04:43 PM
Yeah, Stranger, I'm afraid I want cites about the need for carbohydrates (and about significant carbs being present in animals). An all-protein diet can lead to starvation ('rabbit starvation'), but as far as I know, fats can easily provide enough calories with no carbs at all in the diet. There are many, many examples of humans living for years in Arctic or Antarctic conditions subsisting entirely on animal products.

I understand for some of them the lack of fiber led to constipation, but not life-threatening conditions. So I think fiber is more in the 'optional' category than 'required'. (as opposed to vitamins and other trace minerals which you don't need much of, but definitely do need).

Markxxx
04-08-2009, 05:36 PM
Look at those animal shows and you can see the lions and hyenas and other animals go straight for the organ meats first including the gut. If a lion eats the stomach he's also eating grass and whatever else the prey has eaten.

Animals aren't horribly fussy. A cow in a field basically grazes and puts everything in his mouth. He will swallow it and he learns "that made me sick, don't eat that." Otherwise he will. Then he learns to put stuff in his mouth and spit out what he shouldn't eat.

Most animals at some stage, especially as babies, eat bugs which are full of protein. Even hummingbirds which are nectar machines eat tiny bugs.

If you look at digestive systems of cows they take a long time to digest their food. This is because the food has to stay in the cow a long time so, the cow can extract all the vitimins and nutrients in it. If a human eats the same food, it shoots through them so fast there is no time for the human body to extract the nutrition.

When we send food to starving countries, we don't send them fresh veggies and a variety of food stuffs. We simply send them a mash of soy and oatmeal and other protein rich foods. You can easily live on the same food day in and day out. It's monotomous but fully do-able.

Spectre of Pithecanthropus
04-08-2009, 06:33 PM
Animals aren't horribly fussy. A cow in a field basically grazes and puts everything in his mouth. He will swallow it and he learns "that made me sick, don't eat that." Otherwise he will. Then he learns to put stuff in his mouth and spit out what he shouldn't eat.


"The cow...HE will eat"? What is this, a cock and cow story?

In response to the general question, mammalian carnivore families vary widely in how exclusively carnivorous they are. Some kinds of bears are almost entirely vegetarian (pandas for instance, now again generally considered to be in the bear family after years of being exiled among the raccoons). Most other bears seek berries and other vegetable foods in season, and the greed for honey is factual. Moving on to dogs, I never met a dog that didn't love sweets, like one that we had for years who demanded TicTacs whenever we had them. He needed them too. Cats are the most carnivorous, and they are not horribly fussy either. I had always wondered how a cat goes about actually eating a mouse. I'd assumed it first makes some effort to dress it out, as it were, by removing the skin and fur to reveal the choice parts. But no. Having had the opportunity to watch some YouTube clips, that isn't what happens; instead, they generally chomp down on the whole thing from one end to the other, as you or I would eat a Danish! This is so utterly unlike the cans of Medley that my three boys yip and mewp and pester me for!

Send questions for Cecil Adams to: cecil@straightdope.com

Send comments about this website to: webmaster@straightdope.com

Terms of Use / Privacy Policy

Advertise on the Straight Dope!
(Your direct line to thousands of the smartest, hippest people on the planet, plus a few total dipsticks.)

Copyright 2018 STM Reader, LLC.