A fossil skeleton such as this Mosasaur takes years to assemble, costs millions to buy.

Rocky Mountain Dinosaur Resource Center

Woodland Park, Colorado

If you've been to a natural history museum in the past 20 years, even one in a relatively small city or university, you've probably seen a dinosaur skeleton, or at least a dinosaur skull. And if you've been to as many museums as we have, you start to wonder: where did all of these dinosaur bones come from?

Toothy T. rex: your Dinosaur Resource Center greeter.

Turns out, a lot of them came from here.

The Rocky Mountain Dinosaur Resource Center (RMDRC) is a kind of greatest hits collection of dinosaurabilia, because its bones and bone casts are in hundreds of museums worldwide. Eric Goderis, a long-time tour guide at the Center, told us that the RMDRC is the largest commercial paleontology lab in the U.S., and that its staff unearths prehistoric skeletons at sites across the Great Plains and the American West, and makes money by selling them.

The museum part of the RMDRC, while satisfying to the dinosaur-crazed public, is also a showroom for potential customers. If you have a million dollars and want a mounted dinosaur skeleton, you visit here first to see if you like how it looks.

Aquatic, extinct creatures swim overhead in the Marine Gallery.

Eric enlightened us on the business of dinosaur display. First, you don't call the duplicates made at the RMDRC "replicas." They're "casts," precision copies, indistinguishable from the real thing. The RMDRC makes casts of all of the dinosaurs that it finds, and can sell multiple copies to multiple interested buyers. Eric said that a trick to spotting a genuine fossil skeleton in a museum is to look for the steel frame that holds it together: if it's carefully wrapped around the bones, they're original. A cast copy's bones, however, has its framework drilled right through them.

Dima, the mummified baby mammoth.

An upright dinosaur skeleton can contain several tons of rock, which is another reason to have a cast instead of an original: it's comparatively lightweight, it's less expensive, and if it breaks the RMDRC can just make a new one. But Eric said that the prestige of possessing an original skeleton often outweighs concerns of frailty, budget, and bulk. The Center has no shortage of customers for its genuine bones, and limits the unique and "scientifically significant" ones to buyers from public institutions.

A tour around the RMDRC showcases a mostly terrifying prehistoric menagerie. A Daspletosaurus named Pete is posed chewing on a Ceratopsian plant-eater named Ava, while Stan the T. rex -- a cast of the most expensive fossil in history; $31.8 million according to Eric -- towers over the main exhibit hall. "Mildred," a Xiphactinus horror-fish 18.5 feet long, was a visitor favorite until she was sold to an attraction in Florida, although the Center has several others nearly as huge.

Reconstructed face of a Xiphactinus horror-fish.

Sticking out of a wall like a trophy mount is the head of a Pachycephalosaurus Wyomingensis, which resembles a creature from a bad 1980s sword-and-sorcery movie. Visitors can pose, screaming with mock fright, inside a Megalodon shark's massive open jaws. A mirthfully named "Rex Biscuit" is a Triceratops femur that has clearly been gnawed by something big and scary, while artwork of a giant prehistoric crocodile killing a raptor is accompanied by a description explaining that, "Real life is sometimes not pretty."

Examples of antediluvian cuteness are also on display. Grinning Brachiosaurs and Brontosaurus skulls are posed side-by-side. "Dima," a mummified baby Mammoth, sports tufts of hair on her tiny legs. A genuine T. rex tibia is set out for visitors to touch; an accompanying sign points out that it has the same bone construction as a chicken drumstick (if that chicken was 15 feet tall). The RMDRC also has the second largest dinosaur gift shop in the U.S., according to Eric, and is the nation's principal supplier of consumer-ready dinosaur teeth and claws.

Too colorful? When it comes to dinosaurs, no one knows for sure.

One common misperception about prehistoric skeletons, Eric said, is that they're found pretty much as you see them mounted in a museum: kind of stretched out, maybe a little bent, but mostly ready for reassembly. Instead, as several exhibits in the Center make clear, they're usually found in chaotic piles of hopelessly scrambled, half-smashed bones. "Take the worst puzzle you can imagine," Eric said, "paint all the pieces the same color, and then try putting it together." The staff at the RMDRC has to transform this rocky debris into accurate, action-posed dinosaurs. The Center's "lab tunnel" of viewing windows lets visitors see the paleontologists at work: cleaning, stabilizing, restoring, molding, casting, sanding, painting, and building the fossil fragments into recognizable creatures. Eliminate all of this behind-the-scenes effort, Eric said, and most museum dinosaurs would be just "a drawer full of busted-up bones."

A display of slowly rotating ancient Earth globes shows how the continents have changed over millions of years, so we asked Eric how the RMDRC addressed Creationist visitors who believe that the world is only a few thousand years old. Eric said that a shared love of dinosaurs usually defeats any differences. "We don't have to talk about how old the Earth is," he said. "We can just talk about dinosaurs!" After all, Creationist museums probably get at least some of their dino bones from the RMDRC, like nearly everyone else.