What do animals eat? (And how does this relate to an optimal human diet?)


Humans are very clearly omnivores. Our species eats plants and animals alike and proved that it’s possible to survive on only one of the two (with some supplements, maybe and people differ). We aren’t only omnivores, we are very good omnivores, I mean, we don’t need both for survival or even for ideal health in many cases.

I don’t understand how anyone can eat only fruits even for a shorter but not super short time, that’s so crazy, we aren’t hummingbirds, we don’t primarily need sugar…

I have read that some people can make their own B12, do you know if it’s true? :smiley: Most can’t and sadly, no one can make vitamin C, for example (but we can get enough from meat so there’s that. or maybe not everyone, our needs vary, after all).

Vegetarians should be fine with all their animal products (if they eat them. obviously one can do any diet wrong. I was just an ovo-lacto vegetarian and even with my minimal nutrition knowledge, it was easy to get what I needed - but I did eat a ton and whatever I fancied and could, both helped), vegans have the B12 problem. Well not a big problem, they can supplement it. As almost every health-conscious people seem to supplement micronutrients, I don’t think it matters so much that vegans need to supplement at least one thing. It’s normal in our world. (I don’t supplement anything. Lucky me, I don’t need it and never did except on vegetarian keto, a Mg pill here and there.)

(Edith) #22

But that is the point of this discussion… Animals living in the wild, in their natural habit would not be getting supplements. Humans, also, if we were hunting and gathering would not be getting supplements and therefore, if humans ate an entirely vegan diet, we would not have survived BECAUSE we would not have gotten the essential B12.


I suppose there are such animals if we don’t consider accidental critters on the leaves or something.
Many ruminants are known to eat birds occasionally but I would think a koala doesn’t catch a bird :slight_smile: Or a sloth :smiley:

But it’s probably easier to find strictly carnivore animals (prey stomach matter and medicinal herbs don’t count, okay?). If you are a snake, you won’t eat fruits and leaves even in need… And almost all spider species are strict carnivores.

Chickens are very well-known omnivores. Ducks too. I know little about turkeys but no wonder they are the same in this regard.

It’s NOT healthy for most adult mammals, they become lactose intolerant when they don’t need and drink the milk anymore! Most cats are like this, it’s pretty known but interestingly, not all. Probably it helps if they keep getting milk but many still can’t digest it. And we know humans often lose the ability even if they keep drinking milk. Heavy milk drinker anchestors help :wink: (I just can’t form as good English sentences as I wish…)

Of course it would be quite bad for the species if a mother would need to feed their adult offsprings instead of raising more babies… They got milk until they needed it then didn’t and lost the useless ability…

The same species is the best, of course but sometimes some other milk is better than nothing… Of course it should be somewhat similar. Milks are VASTLY different, fat content comes to mind but I suppose it’s just the top of the iceberg… People raise kittens with formula but IDK what it contains. Something fatty and protein rich enough for them, I have read cow milk is too low on both for a kitten. Maybe it would survive but now that we have vets and choices, we should give them the better thing, closer to their mother’s milk. Hand-raising a wild animal, I am curious about that too…

Yes we should eat things animals don’t (I mean if we want and if it’s good for us, we can choose not to do that and it may be fine too). I like my cooked food and my dairy. Even the noble fruits bred for and by humans but I don’t consider that actual good food, it’s just joy in tiny amounts :slight_smile:
We humans use and do very different things from all other animal species. I won’t stop living in a house and use the Internet either… Just because something is new, it may be good. And we want to thrive, not just survive. Some animal has such a messed up natural diet and lifestyle and everything… But it was enough for survival so it has survived, somehow.

Anyway, we are humans. Even our ancient eating isn’t even remotely similar to some of our pretty close relatives. So you can’t extrapolate much from the diet of great apes if it comes to human’s right diet - let alone the other, more distant groups.

Personally I don’t consider it nice and simple to call not berries berries and berries not berries but it may be me. I like scientific terminology. Where vegetables are nowhere I think… It’s a kitchen term. Fruit is scientific, that’s fine.
I know it’s just me and normal people are fine with kichen/greengrocery’s term. I don’t since the day I learned banana is berry and strawberry isn’t :smiley: But it’s fine, I understand your terminology now and if I ever mention berries in this thread again, it will be the common usage even if it’s wrong.

But vegs… Are there vegs in Nature at all? I don’t even know where the vegs belong, what is their natural relatives, probably it’s all over the place, some tubers, some green leafy things… Of course the animals with the right needs eat them. If it’s a rabbit, leaves work for them. Carrots are too sugary but they still can eat a little. It’s just not their healthy food, more like candy. But rabbits has nothing to do with us anyway, they would die on my fatty diet in no time… They can’t handle sugar nearly as much as humans either. And they aren’t starch eaters like mice… Their food is mostly greens. But why would it matter if it’s vegetable or not? Green leaves are green leaves, they are somewhat similar I would think… Vegetable is a very wide group, an animal may mostly live on one kind and have problems eating more than a tiny amount of another.


I talked about humans, I know that part wasn’t about animals :slight_smile:

But if we talk about plant eater animals, of course they don’t have our human limitations either…

Possibly but what my ancestors in the wild needed has very little impact on my decisions about my current diet. I know many people seemingly want to adapt some ancient diet (good luck to that in this modern world) but I am not among them. I just want a diet that is healthy for me, I don’t care what it would have done to ancient humans without supplements…
(Not like I would supplement - or would ever need it, probably - but that’s not my point :upside_down_face: My point is that I see no problem with a human diet just because there is a need for some tiny, easy supplementing. If one has circumstances where it’s hard to get supplements but animal products are available and affordable, they shouldn’t be vegans. And if both animal food and supplements are out, bad for them. It’s good people are so sturdy or else even more people would die in malnutrition. I am already amazed how poor diets are able to keep people alive for pretty long.)

(Geoffrey) #25

As one who raises livestock I can tell you that the only reason that animals stop suckling is because the mother cuts them off. She stops the feed when it’s time. Otherwise the young animal would stay on the teat. I have seen many calves over a year old that would still suckle if the momma allowed it. I have often witnessed a yearling nursing right along it’s newborn sibling. So the same applies to humans. We are the only species, to the best of my knowledge that allow our children to continue drinking milk long after they no longer need it. I also know of women who allow their children to suckle as long as 2 years and even one who went 6 years.

In my experience, no. While I have not done it personally I do know of many farmers and I have relatives who keep nurse cows. These are kept on a lactation state in order to raise calves who have either been orphaned or bought young and pulled of their mommas too young. They are then put on a nurse cow so they will gain the weight they need and not be stunted.

But we know that animals eat vegetables, of course unless you want to break down the definition of vegetable and vegetation. I personally don’t really see a distinction. Most ruminants with eat mostly the vegetation on the vegetables. We consider the leaf as vegetation but don’t we consider lettuce a vegetable even though it’s a leaf? Nearly all ruminate animals will eat vegetables as well as the vegetation. Corn, carrots, sugar beets just off the top of my head. Because we are not ruminants and what little nutrients in plant matter is not bioavailable to us I’m in the camp that says they are not essential for our health and sustainability do I say no, we don’t need to eat them.

(Bacon is a many-splendoured thing) #26


(Couldn’t resist :rofl::rofl::rofl::rofl:)

(B Creighton) #27

Well, I know the fat, domesticated ones eat processed, refined foods from the kitchen…
and the cows regarded as Prime USDA beef eat lots of GMO grains to increase their weight and sale value… and then most Americans pay extra to buy the trimmed cuts or leaner ground beef…
does that help?


I think the real story as to what wild animals eat begins and ends with scarcity. Much like our ancertors. Scarcity is the norm, meaning that you are not actually eating according to your preferences, and the net result of this is to force diversity/variety into the diet.


Very funny (my kind of humour!) but Im not even sure thats always true! Ive just read that mice sometimes eat their own poo - does that count as food? And Ive read that deer sometimes eat earth / mud - is that food?


Hi everyone, thanks for playing. Really glad to see how many people have commented - I wasnt sure how many people would be interested in this topic.

I read every comment with interest and will try to reply to as many people as possible time permitting.

Ill leave people to comment for a few days and then we can try and see what hypothesis the discussion leads us to regarding what food may be optimal for humans to eat via looking at the animals diet.


I thought its about time that post my answers to the game (I didn’t want to influence anyone’s answers at the beginning):

  1. Other animals (eg meat, seafood, reptiles, eggs, insects)
    Lion -3, anteater -3, shark -3 = 9 points (easy)
  2. Grasses (and related plants)
    Cow -3, sheep -3, horse -3 = 9 points (easy)
  3. Leaves, shoots, trees
    Panda -3, elephant -3, beaver -3 = 9 points (OK but a bit more difficult)
  4. Nuts and seeds
    Squirrels -2, birds -2, mice -1 = 5 points (a lot more difficult than I expected)
  5. Fungi
    Wild pig/boar -1, deer -1, bears -1 = 3 points (very difficult as expected)
  6. Berries
    Turkeys -1, foxes -1, bats -1 = 3 points (a lot more difficult than I expected)
  7. Fruit
    Fruit bats -3, monkeys -2, bears -1 = 6 points (a lot more difficult thanI expected)
  8. Vegetables
    Rabbits -1, wild pig / boar -1, mice -1 = 3 points (really difficult, absolutely the opposite of what expected)
  9. Dairy
    As adults -0 = 0 points (as expected)
  10. Honey
    Bears -1, racoons -1, martens -1 = 3 points (a little bit more difficult than I expected)

My score: 50 points
Maximum: 90 points

I tried to vary the animals in my list to make it a bit more interesting. My score could probably be beaten by a few points by choosing specific animals eg choosing specific species of bird or mice etc.
As for the vegetables category I think my answers may even be stretching it a bit and I think its quite possible to argue that no animals really eat vegetables in their natural environment for optimal health! I really cant quite believe thats the case, maybe someone will counter this finding.
Look forward to seeing what the top score will be. Good luck everyone.


Can turtles get diabetes?


Hi Geezy, thanks for your great insights - that’s really interesting about the milk. I would tend to conclude from what you’re saying is that the reason animals stop drinking milk is not that it is bad for them (rather the opposite) but that for some reason the mother stops it. I wonder why that is then? It is not bad for cows to lactate long term so one may be able to extrapolate that to other animals. So why then? Is it something to do with the suckling process - development of teeth maybe?

Regarding the definition of vegetable and vegetation I definitely do want to make a distinction. Humans don’t eat grass or tree leaves as we dont have the stomachs to digest them. But we do eat vegetables (e.g. cauliflower, tomatoes, carrots), and I want to know how many animals eat these types of vegetables. From my research so far it’s very few and only as a very small part of their diet - and even this may not really be in their natural habitat as it tends to be from gardens or agricultural crops.


Hi Shinita, thanks for your very detailed and interesting input. It’s great to read everyone’s differing points of view. I think it’s one of the best ways to learn. I wont answer most of your points as you made a good case for your opinions. So I’ll limit myself to what I think are two of the most interesting points. Firstly, I think you are in the vast majority with your view that humans are omnivores. As I said before, until very recently (the last few weeks) this was my opinion too. But the more I look into it the less I am convinced that this is the case. When I look at true omnivores like bears, deer, wild boar, mice etc I am not sure we fit in the same category. I am starting to think that the only way we can be considered omnivores is due to our learned ability to cook (fire) and ferment food (storage).

With regard to supplements I agree that in our modern world we may need them to compensate for our nutritional depleted food supply, poor soils, certain health conditions etc However Im trying to work out what constitutes an optimal human diet and if supplements are needed then I don’t consider that diet to be optimal. That’s why for me a vegan diet cant be considered to be optimal for human health.


An interesting point of view, but I’m not really sure I agree. Apart from human induced scarcity which is a different matter, I’m not really sure that naturally food scarcity is a problem for most animals. Maybe at some points of the year such as winter food is scarce but most animals have strategies to deal with that. Some will diversify their diets, others like bears will fatten up then hibernate.


A very good point Janie. While researching my answers to the game I was really surprised to see what diverse omnivores turkeys are, and I included them as one oy answers. We used to have ducks and geese and I once saw one of them eat a dead mouse!


It certainly does help, but not for this thread as want to see what animals eat naturally. However in the future I would like to do a thread about how animals health is affected when they are fed a diet that is not their natural one. I think that could prove very interesting.


Very interesting post Edith, thanks for that. Carnivore sheep - who would have expected that! Just recently discovered the Peak Human podcast - an instant favourite - Ill be sure to look up that episode. Thanks for the recommendation.

(KM) #39


I take it you’ve never personally tried to grow any of these vegetables. There are LOADS of animals more than happy to eat them, from squirrels to deer to pretty much every insect on the planet. And what you call vegetables are human-created hybrids. Animals in the wild do not eat “vegetables” because these items basically only exist in gardens.

This discussion is interesting, but I’m wondering where you’re going with it. Every animal eats according to its physiology and evolutionary niche, which has to do with availability and conditions over very long periods of time. Saying we can figure out what people should eat from what animals eat is the equivalent of saying we can figure out how to breathe under water by carefully observing fish.

(Doug) #40

Indeed they can, though out-of-whack endocrine systems are said to be more rare in reptiles than mammals.