eat. But, for the most part, the animals we eat  don't eat animals – at least not only animals;  

humans basically only dine on herbivores and  omnivores. Why do we steer clear of carnivores? 

Hi, I'm Kate, and this is MinuteEarth. I'm a lover of carnivores and food, so when  

I sank my teeth into this question, I thought I  already had a pretty good idea of what the answer  

was going to be. But there are actually several  really interesting possibilities out there about  

why we generally keep carnivores off the menu. The first reason we might avoid eating  

carnivores – and this was my go-to hypothesis  before this video – is the safety, or really,  

the un-safety, of their meat. As animals  live their lives, they pick up potential  

nasties – things like parasites, microbes, and  heavy metals – some of which can hang around in  

their bodies and cause harm. When one animal eats  another, it adds that animal's nasties to its own  

nasties. When that animal-eater eats another  animal, it'll ingest all that animal's nasties.  

And if something should eat the eater, it'll  nom up ALL those animals' nasties. The idea is  

that eating animals that eat lots of other animals  might expose us to more nasties – and that's not  

great. We do know that certain animal-eating  species do contain high enough levels of  

certain nasties that make them potentially  dangerous for certain humans to consume,  

but we don't have evidence that this problem  applies to humans eating carnivores in general. 

So let's move onto the second hypothesis:  deliciousness; maybe animals that only eat  

other animals just don't taste all that good.  And, because we're dealing with deliciousness,  

I'm gonna hop over into MinuteFood-land for  this one. Now, there are a few reasons why  

carnivore meat might not be particularly tasty;  the first is texture. Carnivores tend to be lean,  

mean hunting machines – they have to be in order  to catch their prey. The leaner and stronger an  

animal is, the less juicy fat it contains and  the thicker its bundles of muscle fibers are,  

so the tougher its meat is likely to be…and in  general, humans aren't big fans of tough meat.  

Then, there's flavor, because what an animal eats  can affect how it tastes – that's why some people  

care whether they're eating grass-fed or grain-fed  beef. Maybe something about eating lots of other  

animals – like the urea critters tend to contain,  or the icky compounds produced when meat sits  

around – makes a carnivore's meat taste gross.  And there IS some anecdotal evidence for this;  

people who've eaten bear during different seasons  of the year tend to say that spring bears – which  

have been gorging on berries – are way tastier  than fall bears, which have been feasting on fish.  

Speaking of fish though, there's a big exception  to this whole “humans don't eat carnivores” thing;  

several of the fish species we eat only eat other  animals, and they don't taste bad – quite the  

opposite, in fact. So I'd go so far as to  say that the taste hypothesis doesn't hold  

up – at least not broadly across all carnivores. Let's go back to MinuteEarth-land to chat about  

the third hypothesis: inefficiency. At least in  modern times, producing enough meat to feed big  

groups of big, hungry humans has generally  required raising animals for their meat,  

and doing this with carnivores doesn't make that  much sense. There's the matter of them seeing us  

as food, but the bigger problem is that raising  carnivores is kind of a waste. If you feed, say,  

a cow 10,000 calories of grass, most of that  energy goes into keeping the cow alive – only  

about ten percent of it goes into building body  mass. So from all this grass, you'll only end  

up with something like 1000 calories of beef –  that's basically just a couple steaks. And if you  

feed those 1000 calories of beef to, say, a tiger,  you'll get only 100 calories of tiger meat. It's  

way more efficient – and easier – to just eat the  beef yourself! It's even more efficient to eat the  

plants yourself, but that's a whole other video.  This hypothesis – inefficiency – is the only one  

that's actually supported by the weird fact that  we do eat carnivorous fish. The very same energy  

loss happens in the ocean too, but since we've  spent most of history just opportunistically  

catching fish – rather than raising them ourselves  – inefficiency here hasn't really mattered to us. 

But there's still one more hypothesis for why  humans don't generally eat carnivores: religion.  

Judaism does not allow the eating of predators,  and the Quran bars eating animals with fangs or  

talons– which discounts lots of animals that eat  only animals. It's not unusual for behaviors to  

start out as religious practices, then spread  outwards and become relatively commonplace;  

humans' avoidance of carnivores as a food source  may have followed a similar trajectory. Although  

note that it's possible – likely, really –  that religious rules about eating carnivores  

are rooted in other reasons to avoid eating  these animals; for example, unsafety – or  

at least people's perceptions of unsafety –  could lead to these kinds of restrictions. 

Deliciousness, too, could be related to  the other hypotheses; like, if carnivore  

meat was risky to consume, it's likely that  we'd evolve a distaste for it – just like  

we've evolved to dislike bitter foods, many of  which contain potentially-dangerous compounds. 

In other words…this carnivorous culinary conundrum  is…complicated. And since nobody out there is  

actually studying it, we don't have a solid  answer for why we gobble up cows and chickens,  

but steer clear of tigers and eagles. But  this question is good food for thought,  

and I, for one, have enjoyed  chewing on the possibilities.

Since we got on our carnivore kick, we've been  having a blast playing Beast Lord: The New Land,  

which sponsored this video. It's a basic  strategy game where you need to explore,  

find resources, and build alliances, but  with a cool ecological twist - which you  

know we love! You can choose from more than  500 animal characters to unlock and play as,  

each of which uses characteristic natural  behaviors to help the team. And let me just say:  

the art is amazing! We're big fans of the lion  character - which you can get once you log in  

for 2 days in a row. In this game, lions act like  squad captains - so when you put one in your team,  

it amps up the rest of the squad's expedition  skills. When the lion's leading the pack,  

its attack powers get boosted, too. And as  your lion gains experience, it increases the  

rest of the team's attack and defense skills  simultaneously, making the whole beast squad  

even more effective. So join more than 10 million  other folks who have downloaded the game, and  

start playing today - get started at the links in  the description. If you use the code MINUTEEARTH,  

they'll hook you up with a bunch of extra  resources right at the start. Thanks Beast Lord!