Biology/Zoology Q: Engineered supersoldier herbivores?

[Townopolis]

Ok, this is probably the strangest question I've ever asked on a gaming forums, but here goes.

In a world I'm working on, one of the races (firbolgs) is the old "bioengineered supersoldier" schtick. Now, as I was making them, I hit upon the idea that it might be cool to have them be herbivores. My justification for why they would be designed this way is that it's more economical to feed an army of herbivores. This brings me to my 2-part question.

Q: Does it work that way?
Q(a): Is it true that an herbivore requires less land/individual to feed sustainably? (I remember reading/hearing in various places that it takes X sq.' to sustain an herbivore and Y sq.' to sustain a carnivore, and Y was larger than X.)
Q(b): Are there any morphological traits that come with the diet that would affect/inhibit the proposed creature in fulfilling its designed role (soldier)?

Misc. other information: The proposed creatures are supposed to be largish humanoids, designed to withstand long-extremely long periods of significant activity (forced march, fortify camp, take watch, break down camp, forced march, lather, rinse, repeat), and also be capable of short bursts of heightened activity (storm the trenches). They may also have 4 eyes to provide a wider field of vision, although I'm still wondering what other ramifications that might have.

Bonus Q: I understand some animals (horses) develop real issues when fed only once/day. Is it plausible for an herbivore to be able to process 1 meal/day without issue?

[Doomsy]

A herbivore tends to be more dangerous in some ways than a predator. You shoot at a wolf, it is likely to run. You shoot at a cape buffalo and you pray to God you hit it on the next shot because it is coming over to say hello at a full out charge. A lot of them are actually way more aggressive then predators. You do not even want to get close to a hippo, period.

The feeding thing might be an issue. Herbivores, especially large ones, tend to need a lot of vegetation to support themselves. Now, science might be able to help this out a lot if they are engineered - you could use extremely high calorie rations for them, and a highly efficient digestive system.

About the other issue I can think of for behavior is, well. The gender issue. Usually in herbivores gender roles are very, very defined, and you do not often have males peacefully existing in large numbers. You have a few alpha males and their harems. Matriarchy might actually work here better than an army of males.

The four eye thing is kind of weird. I honestly can't think of a higher lifeform with multiple eyes. Maybe someone else can. I know we have our eyes set as we do because depth perception is vital for hunters, while herbivores tend to go for placement that allows for a wider field of vision in general.

[Lyndworm]

Ok, this is probably the strangest question I've ever asked on a gaming forums, but here goes.

In a world I'm working on, one of the races (firbolgs) is the old "bioengineered supersoldier" schtick. Now, as I was making them, I hit upon the idea that it might be cool to have them be herbivores. My justification for why they would be designed this way is that it's more economical to feed an army of herbivores. This brings me to my 2-part question.

Q: Does it work that way?
Q(a): Is it true that an herbivore requires less land/individual to feed sustainably? (I remember reading/hearing in various places that it takes X sq.' to sustain an herbivore and Y sq.' to sustain a carnivore, and Y was larger than X.)
Q(b): Are there any morphological traits that come with the diet that would affect/inhibit the proposed creature in fulfilling its designed role (soldier)?

Misc. other information: The proposed creatures are supposed to be largish humanoids, designed to withstand long-extremely long periods of significant activity (forced march, fortify camp, take watch, break down camp, forced march, lather, rinse, repeat), and also be capable of short bursts of heightened activity (storm the trenches). They may also have 4 eyes to provide a wider field of vision, although I'm still wondering what other ramifications that might have.

Bonus Q: I understand some animals (horses) develop real issues when fed only once/day. Is it plausible for an herbivore to be able to process 1 meal/day without issue?

Carnivores don't require any land what-so-ever, they only require meat, which can often be obtained just by doing a super-soldier's job (killing things made of meat). Herbivores don't technically require any land either, just the food. However, that food takes a lot of land to grow. (The same could be said of carnivores if you think about it. they don't need plants, but they need things that need plants, making the land almost as important to them.)

With the right digestive system, you could get most of the nutrients you need by eating rocks, so the choice between herbivore and carnivore doesn't affect much of the physiology. However, if they're like the modern mammals with which I am familiar, then the herbivores will probably have a stockier build and much larger guts than the carnivores. They need larger guts to give them more time to digest hard-to-digest foods like vegetation.

However, the extra weight isn't necessarily a bad thing. It would slow the creatures down, sure, but it would probably make them tougher, as well. Nature has a way of compensating like that.

Some guidelines to follow would be that herbivores (generally speaking) have worse eyesight, have more clearly defined sex-roles, tend to live and work better in groups, and are going to be slower but tougher than carnivores.

My personal suggestion, of course, would be to go with omnivores. Compared to a strict-feeder one way or the other they might seem boring and unoriginal, but they're far more efficient at adapting. Besides, ravenous creatures that kill me and eat my crops are frightening; Ravenous creatures that kill and eat me are a little bit more frightening; Ravenous creatures that kill and eat me, everyone in the town, all the animals, our rations, the crops, the grass, the trees, and all of our garbage are absolutely terrifying.

As for multiple eyes, I'd suggest giving them the Wide Vision ability.

Wide Vision (Ex): Because of its multiple eyes and wide angle of vision, this creature has a +4 racial bonus on Spot checks and cannot be flanked.
-Taken from the Insectile template from Savage Species.

Zack

[Sstoopidtallkid]

I seriously thought you were doing an Animorphs thing when I read the title. Spoiler if you're interested:

Spoiler

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The Hork-Bajir were a 7' super-strong race created with limited intellect created to keep trees healthy by farming them and eating the bark using naturally-grown blades out of their wrists, elbows, knees, and head. The Yeerks could control the minds of others. When the 2 meet, instant super-soldiers.

What's your justification going to be for why these beings obey their creators? Remember the War Elephants of ancient times? They were as big a danger to their own side as the enemy. Just charging buffalo at the enemy is a guaranteed way to lose your herd of buffalo if the enemy has pikes.

[Ulzgoroth]

Agriculturally produced or naturally occurring food is, in any remotely normal environment, going to produce more plant nutrition than animal per acre, since the animal's meat value is strictly (quite a bit) less than that of the plants they consume.

However, the additional digestive system needed to break down plants, especially the really powerful setups used by animals that live on foliage (rather than, say, nutrient-rich tubers), imposes a definite weight/bulk penalty, and that is a penalty...if there's any side advantage at all, it might possibly give you better water uptake. But I doubt even that. It certainly won't improve your survivability as much as the same mass of some other sort of tissue. Internal organs are all bad things to take damage to. Carnivores, operating on a 'you are what you eat' basis, have much more compact guts.

The heavy penalty is somewhat specific, though. As humans regularly demonstrate, if you're eating the right plant material you can get a lot out of it with a much more modest digestive system. If you don't need your supersoldiers to be able to live off hay and leaves, they don't need a specialized herbivorous digestion. There's probably no reason to make them obligate herbivores, regardless. The ability to digest meat is probably worth whatever the additional cost is. It probably wouldn't be much, especially if you're already giving them strong immune systems (meat has a lot more potential to get you sick than plants).

Four eyes might require some additional brain capacity to process the extra data, but shouldn't have any serious added ramifications. Two eyes is a good, practical number (minimum for depth perception, also conveniently minimum for 360 field of view), but having more shouldn't hurt anything.

[ninja_penguin]

On the biology side of things, it would be more energy efficient for you to have herbivores as your supersoldier instead of carnivores. You can probably handwave the really hardcore biology (i.e. the required intake of protein that you see in more intelligent animals, or the protein needed for efficient building of muscle mass) with either 'A wizard did it!' or making them omnivores. And if they were total carnivores, you'd need roughly 10 times the amount of grain produced to feed them, as the step from primary consumer to secondary consumer is roughly a 10:1 energy loss.

Physically, they're going to have thick flat teeth, which is a fun subversion of the standardized fangs. Some other stuff that you could pull from biology and make super soldiery:

1. Give them multiple stomachs, and let them be able to survive for extend periods of food if they've gorged at some other location. They could possibly strip an area down to the ground, like some sort of locust, before going on a campaign somewhere else.

2. Large size and bulk would make them better suited to colder climates.

3. Re the four eyes: Two eyes should be placed in front for binocular vision, as this is required for depth perception. Place the other two back and slightly to the side, and this will give them a better overall peripheral field of view.

[vrellum]

A couple of comments.
1st Herbavores are more economical to feed. They are primary consumers, while carnivores are secondary, tertiary, etc. Every step you go up the ladder, the more energy is wasted.

However, this might not be as big of an advantage as it sounds like. Plant material is a lot less energy dense than meat. Herbavores need to a lot and they need to eat often. A cow will eat 20 to 30 pounds of grain a day or maybe 60 or 70 pounds of hay, they also drink about a bathtub full of water per day. Granted they're big, probably bigger than your supersoldiers, but still a big herbavore is going to need a lot of food. And they are going to need to eat it often.

2nd herbavores do not eat meat. That's by definition. So if you come across a bunch of meat, it's not any help to you.

3rd. Carnivores and omnivores can eat more energy dense foods (meat) and they don't need to spend as much time eating.

4th. Predators tend to have better natural weaponary and they know how to use it better. Granted cape buffalo, hippos, bison, etc. are very dangerous, but a 2000 pound tiger would also be pretty scary (not to mention a 4000 pound one, if it was hippo-sized).

I think it would make more realword sense to make your super soldier an omnivore. Eat a wider variety of food. Wouldn't need to eat as often. Food is lighter.

[Fishy]

If you're really looking for energy efficiency, use bugs. Mammals have to burn a lot of energy just too keep their body temperature up and run their circulatory systems, whereas bugs cheat. The German Water Cockroach converts something like 42% of its food directly into body mass.

The problem, of course, is scale. If you double something's height, you multiply its surface area by a factor of four, and its volume by a factor of eight. Bugs 'breathe' through a network of tiny holes in their carapace, and if they suddenly had more thickness than surface area, that stops working.

But on the other hand, GIANT BUG SOLDIERS!

[Suzuro]

4th. Predators tend to have better natural weaponary and they know how to use it better. Granted cape buffalo, hippos, bison, etc. are very dangerous, but a 2000 pound tiger would also be pretty scary (not to mention a 4000 pound one, if it was hippo-sized).

Remember, though, that these are genetically engineered, so this is a moot point, they could give them any weapons they wanted and make them blood-thir....well....killy...

And, yes the energy required for primary to secondary consumers is indeed an exponential through the power of ten, so they require less, theoretically. But the problem, as others have said (I always end up reiterating other people...) is that vegetation is less dense in nutrition/energy.

That being said, I think it definately would be cool to have herbivore soldiers, it gets a cool kind of ironic two sides, the killer soldier, and then the (normally) docile herbivore.

I would also second giving them multiple stomachs, and, since you're already talking about genetic engineering, it probably wouldn't be too much to either make their digestive systems/storage systems much more efficient or created some type of supermeal for herbivores.


-Suzuro

[vrellum]

Remember, though, that these are genetically engineered, so this is a moot point, they could give them any weapons they wanted and make them blood-thir....well....killy...

And, yes the energy required for primary to secondary consumers is indeed an exponential through the power of ten, so they require less, theoretically. But the problem, as others have said (I always end up reiterating other people...) is that vegetation is less dense in nutrition/energy.

That being said, I think it definately would be cool to have herbivore soldiers, it gets a cool kind of ironic two sides, the killer soldier, and then the (normally) docile herbivore.

I would also second giving them multiple stomachs, and, since you're already talking about genetic engineering, it probably wouldn't be too much to either make their digestive systems/storage systems much more efficient or created some type of supermeal for herbivores.


-Suzuro

It depends on how much you're going to genetically engineer them. Also, for example, carnivore teeth generally need to be deadly to be functional. Herbavore teeth could be, but pointy teeth that are capable of slicing and tearing generally wouldn't work well for a herbavore, genetic engineering or no.

[Greenfaun]

Well, first of all, if they're bio-engineered, you don't really have to worry about what goes with what in nature, because they're not subject to evolutionary pressure and their creators can give them whatever they want them to have.

Other people have already gone over the herbivore/omnivore problem. One more thing, though- are they meant for a defensive or a conquering army? If they're defensive troops for garrisoning agricultural villages, making them herbivorous is fine, because they're right next to their food source. On the other hand, if their owners want to conquer territory with them, that means they need a supply train, and that means it's more efficient to feed the army energy-dense high-calorie foods like nuts and grains and meat.

If, on the other hand, you want them to be able to live off the land wherever they are, then being grazers who can eat low-density foods like grass and bark is good. If that's their diet, though, they do need to eat a lot of it. They could be like locusts (or elephants), wiping every bit of living plant matter out of an area and then rolling on to the next one.

This could mean they could desert their overlords' army rather easily though. If loyalty is an issue, perhaps their designers made them able to eat only one particular kind of magic bean, and it doesn't grow anywhere but in lands they already control.

Basically, to come to my general point, decide what characteristics the people who made them wanted, and give them those characteristics. Don't be afraid to go dark. A bio-engineered race of slave-soldiers is already pretty dark, don't start pulling your punches now. :)

Also, I like the four eyes thing. Have you considered eyestalks? Human soldiers have to resort to tricks like a mirror on a stick to look around corners or over walls without exposing their heads to fire, but with eyestalks your firbolg could just peek over, and they could look in any direction the rest of the time. Plus, y'know, scary mutant appeal. :)

[Danin]

Although I'm not much for biology, I do know what its like to eat in the field. Namely, you eat a lot. An average soldier during regular operations will require between 3500 and 6000 calories a day, or roughly twice as much as a normal human. This number, under extreme conditions, can jump to as much as 9000 calories a day. This is a lot of food. Being that veggies and the like are typically not nearly as calorie dense as meat, this is going to require a lot to feed them. Remember to take this into account. If they are exceedingly large creatures, this number is going to be even higher. The idea of multiple stomachs is probably a good one, and the ability to store energy energy somehow would be critical in the development of super soldiers.

I think one thing that would be of note is that if they did have a great amount of muscle mass and a body genetically engineered to replace muscle mass quickly, this can be converted into energy during long periods of inactivity. While this does mean that their muscles would atrophy, if they had a mechanism of replacing this quickly, they could theoretically remain inactive/minimally active for long periods of time and last for days, maybe even weeks.

As to 4 eyes, it would probably grant uncanny dodge or the like and a bonus on spot checks. Herbivores generally have poorer vision but a much greater field of vision as their eyes are on the sides of their head, as opposed to carnivores which generally have great vision but a more narrow field of vision.

[Fishy]

Well, first of all, if they're bio-engineered, you don't really have to worry about what goes with what in nature, because they're not subject to evolutionary pressure and their creators can give them whatever they want them to have.

You don't need to worry about nature, but you do need to worry about chemistry and physics.

If, you know, you decide to worry about chemistry and physics.

[Suzuro]

If, you know, you decide to worry about chemistry and physics.

Who says?


-Suzuro

[Doomsy]

A superdense form of ration might work, if you focused purely on raw calories and enriched the sucker a lot. It might or might not be good for them long term, but they're basically replaceable if you can make them in sufficient numbers to field armies. I came up with something similar once as 'fuel' for some devices that worked on digestion to generate power, but it was pretty much a processed grease/fat mix that would probably...well, do very very bad things to an organic system that actually was more than just a power generation source.

For something like this, you'd probably need something based purely on vegetable matter. Peanut butter esque, maybe, but condensed and hardened into pucks. Legumes, tubers, potatoes, starches. Carbs instead of protein or raw vegetable matter.

[Leewei]

If we're talking D&D here, just make them Plant type. :)

[Sstoopidtallkid]

You don't need to worry about nature, but you do need to worry about chemistry and physics.

If, you know, you decide to worry about chemistry and physics.

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[Lemur]

I'm not sure if anyone's mentioned it yet since I haven't carefully read every post, but pure herbivores are also at risk of scorched-earth tactics. If you're invading and you're enemies get desperate (which seems likely if they're dealing with supersoldiers) then they might very well burn their fields and granaries as they retreat, just to keep it from your hands (plus ruining the fields for years for future use if they also salt their fields)

There's also the issue of transporting the food. As others have mentioned, herbivores generally need to eat a greater mass of food to function, even if the total land used to produce that food is less. This is going to be important if your army is on the move. If they're just sitting pretty as castle guards, perhaps not so much, but there's still the issue of food during sieges.

Omnivore seems like a good bet to me, particularly if they can eat any type of meat (including cannibalization). Humans, for one, have been able to go without food longer if they've previously gorged on meat. Someone mentioned eating rocks and dirt as well as a possibility. If you engineered a symbiotic fungus or bacteria type that lives on or inside them, you might be able to increase either their digestive capacity to rotting material or even fecal matter.

[Greenfaun]

For something like this, you'd probably need something based purely on vegetable matter. Peanut butter esque, maybe, but condensed and hardened into pucks. Legumes, tubers, potatoes, starches. Carbs instead of protein or raw vegetable matter.

Lembas! [/oldschool] :)

[Asbestos]

This could mean they could desert their overlords' army rather easily though. If loyalty is an issue, perhaps their designers made them able to eat only one particular kind of magic bean, and it doesn't grow anywhere but in lands they already control.

Since we're already designing these guys... why not just make them unable to produce some random amino acid/vitamin? Obviously not something common like pantothenic acid, but something that's a little harder to come by. Since these guys are apparently going to have high nutrient demands they'll have higher demands for said hard to get vitamin as well.

Other things to consider. Possibly have these guys capable of a sort of ability to hibernate/estivate (didn't see if someone suggested this) for when these guys are 'in reserve', otherwise they're going to be a completely ludicrous drain on resources. I mean, a tank when it isn't warring isn't really using up that much, a war horse is burning resources 24/7.

Digesting rocks is pretty much out of the question, the energy needed to do it at any reasonable speed probably surpasses the energy gained.

I can't think of how many calories these guys are going to eat up, but thanks to their size they might not have to spend as much on thermal regulation as smaller animals. Also, I think the metabolic efficiency of insects, if I recall, is size related. Therefor its pretty much irrelevant that roaches are more efficient than elephants.


I'm agreeing with the people voting omnivore.

And I'm curious, what's the life-cycle for these things?

[Coidzor]

They're dependent upon herds of plant-type warbeasts that are magically capable of growing only so long as their evil overlords desire them to grow (or in certain actual terrain types or something) for their nutrition.

Like... They eat the nuts or flesh of their mounts and warmachines. Which can grow back or... y'know, just grow anew from the ground.

[Asbestos]

They're dependent upon herds of plant-type warbeasts that are magically capable of growing only so long as their evil overlords desire them to grow (or in certain actual terrain types or something) for their nutrition.

Like... They eat the nuts or flesh of their mounts and warmachines. Which can grow back or... y'know, just grow anew from the ground.

Now, rather than denuding the landscape, we're depleting the soil... which is going to make it pretty worthless for the conquerors (if they want to grow anything anytime soon)

[Coidzor]

Now, rather than denuding the landscape, we're depleting the soil... which is going to make it pretty worthless for the conquerors (if they want to grow anything anytime soon)

Hey now, if people are able to do anything with the land after they burn down the rainforests, it's not like this is going to instantly turn fertile croplands into dry-bones dusty deserts or anything.

Depending on how high the magic is, anyway, the plants would mostly be needing water and sunlight except for bivouacking at night during extended campaigns/healing growth. No magic and the system becomes unworkable anyway, since it seems more trouble than it's worth to make mobile, sentient plant warmachine-beasts with super science.

Besides, it's not like they'd be depleting every acre of the soil, just where they're physically bivouacking, which just makes it all the more hardcore when they salt the earth after destroying a city.

[Fishy]

Someone mentioned eating rocks and dirt as well as a possibility. If you engineered a symbiotic fungus or bacteria type that lives on or inside them, you might be able to increase either their digestive capacity to rotting material or even fecal matter.

Again, if we decide to care about chemistry, the energetic content of your average rock is basically nothing. It's fine for minerals to create exoskeletons and things, but your metabolism needs to be fueled by something else. If we don't care, rocks are rich sources of Elemental Earth energy, part of this complete breakfast.

Fungi are awesome, though. I've been thinking, on and off, about a fungal fantasy race- they grow until they hit a certain size or density, then give birth to some sort of Monstrous Humanoid thingie that lays waste to the surrounding countryside, then collapses into a puddle of spores and digests the remains. Like slime mold, but with berserker warriors.

[Prometheus]

The comments about evolution not be a consideration and the spoils of war being a major consideration are dead on. More to the point, if your PCs don't know biology than you need only to concern yourself with common perceptions about biology.

I say not only make them herbivores, but herbivores that can digest just about anything that isn't meat and have a voracious appetite. As they sweep across the land, the farmlands are dredged to feed the army. It's not just harvested, there is literally not a bit of the original roots system. When the retreating forces burn their crops to deter the army, they find the army shoveling the ash into their mouths. As they pass through forests, they tear down trees. As they pass through cities, they pull the planks from the houses. These foe play total warfare, and they aren't concerned about what is left to be conquered. How does this work? Magic. Or if you want a better explanation, they are able to pass rock and dirt through their system but only gain nutrients from plant matter that is found in it.

It reminds me a lot of the koloss from the Mistborn series. If you make them anything like them, than you have an awesome army.

[dspeyer]

Is there any connection to the Firbolgs of Irish mythology?

As for food, the basic rule is that fat is twice the energy density of protein, starch or sugar (which are equal). How cellulose fits in depends on how the digestive tract works. Whether the nutrient is animal, vegetable or chemical in origin doesn't matter.

Yes, meat requires a lot more sunlight of original input per calorie to produce, but this probably doesn't matter. No army carries an agricultural society with them -- they carry rations (see above). Even if they "live off the land", this mainly means robbing the local populace, which may be farmers, herders or some combination.

Carnivores are usually smarter. If you're tacking on human-like intelligence anyway, this may not matter.

Herbivores are usually bigger. Again, genetic engineering lets you do whatever you want.

[Townopolis]

Aight, so lots of opinion that we should probably go omnivore, but also some interesting ideas for an herbivore. The main issues I'm seeing are getting lots of calories to these guys on campaign, and the amount of real-estate that'll be taken up by their digestive tract.

Regarding the eyes, I was planning on the first pair having normal human placement, and the second pair being slightly lower and around where our cheekbones might be, the idea was to grant a wider field of vision, with depth perception throughout. However, having "eyes on the backs of their heads" would be cool as well.

Hibernation mode is also quite interesting and promising.

I also once had an idea for a symbiotic plant which grew where hair normally does and collects bonus calories via photosynthesis, but I abandoned that for lack of having any idea how it would work.

Now, some lore.

The world of Hibernia (Hey, if Fable can use Albion, I can use Hibernia, dammit) is currently a post-apocalyptic one, except it's so post that the apocalypse is only legend and it's basically back in the middle ages. It's a fantasy world where the "gauntlets of blasting" you found in an ancient tomb are actually high tech, not just magic. Actually, a lot of tech is magitech, and higher magic than is available in the present (since elves took most of the magic behind the veil with them).

But I'm trying to avoid any magic pills here.

The firbolgs were originally built pre-apocalypse. When they were designed, they were pretty much intended to replace human soldiers for a few, powerful human nations (humans and elves are the only original races). Their primary purpose was as a defensive army, but they are intended to be able to act in almost any function that you would find America's military acting in. This pretty much necessitates an easy way to get lots of rations to them, either a suped-up power bar, or whatever else we could think of.

The world of their creation was (obviously) more advanced than even modern Earth (they have precise bioengineering) but perhaps that's just because they have the benefits of magitech (again, not for handwaving). The world is notably better off environmentally than modern Earth, but with notably more political/military problems (it ends with an apocalyptic species war between humans and elves), these guys would be pretty active.

The method of control I was going to go with was going to be psychological. One idea was to take space for the extra optical processing from the segment of the brain normally devoted to long-term planning (again, not a neurologist), thus making firbolgs poor at thinking strategically, making them reliant on human generals and society. Ideally, they would also be designed so that they are social creatures of habit, while not destroying their adaptability. They are supposed to have human-grade intelligence overall.

Currently, it's a middle-ages style setting, this means they'll need to be able to support themselves. On the other hand, this also means they're mostly operating on their own terms, or as part of someone's guard, or as part of a much smaller scale of army. I'm imagining most firbolgs will become territorial, with only a small percentage preferring to adopt a more migratory/vagrant lifestyle.

I'm planning to build these for 4e. Firbolgs will be medium creatures with the oversized trait.

[hewhosaysfish]

Their primary purpose was as a defensive army, but they are intended to be able to act in almost any function that you would find America's military acting in.

From what others have been saying, this sort of flexibilty would be best supported by equal flexibility in their diet. So, ominvore? Also if they were intended to operated in different climates and on different continents then the whole "eat absolutely everything" idea also gains traction.

One idea was to take space for the extra optical processing from the segment of the brain normally devoted to long-term planning (again, not a neurologist), thus making firbolgs poor at thinking strategically, making them reliant on human generals and society.

Poor enough at long term planning that have to they rely on humans... but not so poor that they don't see the undesirable consequences of deciding to crush the puny humans who keep bossing them around...
This is why I don't genetically engineering things to be stronger and tougher than me in every way. (That and my complete lack of biology qualifications or high-tech labs).

[Epinephrine]

Re: energy density.
Fats are roughly 9 Calories per gram, both Carbohydrates and Protein are roughly 4 Calories per gram. That being noted, transporting food with a vegetable fat (oil) ratio as high as meats have animal fats, and with a carbohydrate portion as large as the protein portion for meats would provide the same energy per weight.

I wouldn't worry too much about speed, herbivores can be plenty fast. The two fastest land animals in the world are the cheetah (carnivore) and the pronghorn (herbivore), and they're not that different in speed. The pronghorn doesn't quite have the top velocity that a cheetah has, but can sustain it much longer.

[JBento]

Sidenote: You may want to consider the option of making them reptilian, or some other ectothermic creature. Though this will suck ass (big time) if you want to invade cold climates, temperate and warm climates will allow your critters to subsist with substantially less food - a lion eats 10 times as much as a crocodile, and most of that goes to internal temperature control