Assuming that we could teleport an adult Tyrannosaurus rex into a present-day zoo, how much would it cost to feed it? How would this cost compare to what it costs to feed other modern-day terrestrial predators typically found in zoos (lions, wolves, etc.)?
If I’m reading the auction reports here, correctly. Then it looks like beef cattle are selling for about $140/head. (Admittedly, this seems low to me, but I know diddly about the beef industry.) Now, if T. Rex has a slow metabolism like a lizard does, then you could probably get away with feeding it a cow a day (this would be ideal, because people would pay big bucks to see a T. Rex chase down Elsie the cow and chow down on some rare burger), which means it’d probably cost you about $50K/year to feed the thing. An expense easily recouped by the increase in ticket sales that having a T. Rex on hand would net a zoo.
They already do this with Rosie O’Donnell. 
I know even less about the cattle industry than you do, but I think the prices are quoted in hundred weights. So a 750 lb steer might sell for $125/cwt or a bit under a $1000.00. So you’d be paying more like $300K-$400K/year to feed the T-Rex. It would be cheaper to set up an amusement park and randomly cut power the electric fences.
It’s going to be pretty hard to guess what the caloric intake of a T-Rex was. Last I heard, there was still some dissent about whether they were cold-blooded or warm-blooded. If cold-blooded, I imagine they could just eat one cow and then go bask in the sun for a couple of weeks.
If warm-blooded – well, a T-Rex might weigh a bit more than a large elephant, and elephants seem to only eat about 400-500lbs of vegetation/day. I’d guess that animal protein is denser in calories, so you might get away with half a cow per day.
Then again, I’ve heard that birds are the nearest descendents to actual dinosaurs, so feeding a T-Rex might just cost chicken feed.
IIRC, birds eat something like twice their weight or more a day. (Oh yeah, your analysis of the prices makes more sense than mine does.)
No, not nearly that much. Even hummingbirds may only consume about their own weight in nectar in a day, and most of that is water.
Remember that energy requirements are proportionately much greater for small animals than they are for large animals. Elephants consume only about 5% of their body weight per day. (For a 5-ton elephant this is equivalent to about 500 pounds, as mentioned above.) As Finagle mentioned, meat is much more energy-dense than vegetation, so a T. rex might only need a few hundred pounds of meat a day.
In John Kessel’s Corrupting Dr. Nice, a scientist brings a dinosaur to the present. Kessel does a great deal of examining the food and waste problems that entails.
What’s the largest land based carnivore species currently alive, and how much does it eat? Actually whats the largest overall, and the largest in both cold and warm blooded categories?
The sperm whale is the largest currently-living carnivore, the saltwater crocodile is the largest cold-blooded carnivore, and the polar bear is the largest land-based predator.
psychonaut, thank you for asking such an interesting question! I’ll be here, on the sidelines, watching the action.
Other considerations besides cold vs warm bloodedness, are climate adaptations, like hibernation. Cold weather animals require higher fat layers than their warm weather counter parts.
That’s all I have.
Nothing. Let it loose in NYC and let it feed for itself. 
Well, food wouldn’t be the only expense, I imagine the insurance premiums would be quite high to cover the possible lawsuits if it breaks out and eats the park visitors or runs rampant through the city.
Not a problem. I would assume anyone that had a pet T Rex and was wondering how much per day in meat it costs to feed an archosaur, wouldn’t really worry about the insurance cost, as they would be an “evil villian” and wouldn’t pay insurance anyway.
Hey! What do you think you are? Some kind of bird expert? 
True. Not knowing the metabolic rates for a T. Rex makes answering this question difficult. It’s entirely possible that dinos could have a metabolic rate with which we’re totally unfamiliar with. Hopefully, some evil genius will figure out a way to clone one and we’ll know for sure.
But silenus! Think of the poor beast’s welfare!
New York is much too cold for T. Rex’s good health!
Calfornia has a much more suitable climate.
An arm and a leg.
I’m sure they could cover a lot of the cost if they did it like petting zoos do. Have those coin operated food dispensers that allow visitors to feed the animals themselves. Of course, in this case they wouldn’t dispense those little food pellets kids feed to the goats and pigs at the petting zoos. At the T-Rex pen the dispenser would probably contain goats and pigs.
[Leela] Remember, keep your palms flat! [/Leela]
I think this is more a question for the Christian community. Just ask them to check their records.
Well, let’s say, for argument’s sake, that T. Rex behaves a lot like a modern big cat - That is, to say, that it can eat hugely when food is available, then lounge about for some days afterwards. Alternatively, if fed daily, they can eat considerably less at each go, and still be happy.
In fact, let’s just go with the big cat metabolism as a starting point. It’s as good a guess as we’re going to get, IMO. Now, a BIG big cat can chow on up to 25lbm of meat a day. This is up to 7% of body mass, daily. In captivity, the big cats lead a mode sedentary life, and consume an upper limit of 6% of their mass per day. I think it’s safe to presume that our captive thunderlizard will be leading a pretty tame life.
T. Rex may have weighed as much as 8 tons. But that’s problematic. Some researchers, looking at bone structure and other features of T. Rex fossiles hypothisize a weight as low as four tons. I’m going to say 6 tons, to split the difference
If we do a simple direct scale, then our zoo-bound T. Rex could be eating as much as 720 pounds of meat a day. Or basically, one large steer, daily. If, however, you were going to go with the gorge-n-snooze approach, T. Rex could be eating a small herd of cattle at a go!
Looks like Finagle called it, IRT cost. Or at least as best as can be guestimated, knowing what we currently know.