Bakker Blogs: The kleptomania continues with a Sid Vicious Julieraptor — Dino Rustlers Part II

Part Two: Julieraptor — The raptor rescued from rustlers.

Small and mid-sized raptors swarmed over the landscape in the Late Cretaceous. Velociraptor, as heavy as a coyote, haunted the sand-dunes of Mongolia. The Rocky Mountain states hosted Bambiraptor, a predator no bigger than a rotisserie chicken. Here is our cast of “Julieraptor,” a close relative dug from near Malta, Mont.

julieraptor
Courtesy of Black Hills Institute of Geological Research, Inc.

These mini-raptors were big-brained by dinosaur standards — as smart as a wild turkey (not the dumbed-down domestic version).  Their eyes were huge — an adaptation for chasing nimble prey, like furry mammals and tree-climbing lizards. The extra-long arms and fingers gave the raptors three-dimensional abilities — they could scramble up trees quadrupedally, grabbing branches with claws on front and back paws. Long feathers on the arms and legs let the raptors glide from branch to branch like dino-flying squirrels.

Even little raptors could be dangerous to larger dinosaurs — these carnivores were armed with the standard raptor-fighting claw on the hind leg, a weapon that could inflict ghastly wounds.

“Julieraptor” played a central role in a modern-day case of dino-rustling. The original specimen was found in 2002 by a crew of talented amateurs working with the local non-profit museum in Malta, Mont. Mark Thompson, a leader of the group, nicknamed the animal after his sister, Julie. Mark picked up some finger bones and claws and bits of the skull. These fossils were lying on the surface where the rock had been washed away by rain and wind. He suspected that most of the skeleton was still buried in the ground, but he didn’t dig down.  Since the spot was on a private ranch, the fossils actually belonged to the land owner, so the crew would have to wait until the museum and the land owner could negotiate a full excavation. The original box of fingers and bits stayed in a museum drawer.

A few years later, another individual working with the Malta museum claimed to have found a second raptor from a totally different spot in another Montana county. He planned to make money for himself by selling replicas of the skeleton, which he nicknamed “Sid Vicious.”

But the folks from the Malta museum became suspicious. This “new” specimen was exactly the same size as Julieraptor. And the anatomy was exactly the same, too. Even the color of the bones matched perfectly. The two specimens seemed to be from identical twins. Finally, the museum crew compared the finger bones of both specimens side-by-side. The broken ends of the bones of Julieraptor fit precisely onto the hand of “Sid Vicious.”

Then museum investigators went out to where the original Julieraptor bones had been picked up from the surface. There was a huge hole. Clearly, someone had snuck in and excavated the rest of the skeleton.

Case closed! There was no second Sid raptor. All the raptor bones came from one and the same specimen. The fellow who claimed to have found “Sid Vicious” was a raptor-rustler! He admitted his crime and spent several months in jail. The skeleton was returned to the land owner, who arranged to sell the specimen to the Royal Ontario Museum, a non-profit institution which specializes in Late Cretaceous dinosaurs.

Our cast of Julieraptor was made by the Black Hills Institute of Geological Research, who worked closely with the land-owners.

Could T. rex catch a duckbill? And other dino questions answered.

[Ed. note: Recently, a reader named Wyatt left a comment on the blog asking HMNS Curator of Paleontology Dr. Bob Bakker a few questions about dinosaurs for a high school paper. We thought we'd share the answers with everyone - as well as wish Wyatt luck with his paper.]

1) Which predatory dino was the largest?

T-Rex Dinosaur
Creative Commons License photo credit: Scott Kinmartin

The longest probably were the North African spinosaurs or the Argentine giganotosaurs; both families pushed 50 feet.

But tyrannosaurs were chunkier – thicker neck and torso. So tyrannosaurs would be heavier for any given length. A 40 foot long tyrannosaur would be heavier than a 50 foot spinosaur.

Strongest bite was had by the tyrannosaurs – much wider across the back of the head than giganotosaurs or spinosaurs.

2)  Which would dominate?

That depends on the habitat, geography and geological time. Big tyrannosaurs didn’t live with spinosaurs or giganotosaurs. Tyrannosaurs are restricted to Mongolia, China and North America. Tyrannosaurs did live with many kinds of raptors – including Velociraptor, Bambiraptor, Dromaeosaurus, Saurornitholestes. 

All raptors are smaller than all Late Cretaceous tyrannosaurs. The smallest tyrannosaur is Nanotyrannus, Late Cretaceous of North America, about 1,000 pounds in weight. The biggest raptor of the time was only 100 pounds or so.

Tyrannosaur
Creative Commons License photo credit: matsuyuki

But…..there were many more raptors alive at one time than Nanotyrannus. Just like today – there are many more coyotes than grizzly bears. Raptors were too small to attack adult Triceratops or duck-bills. But tyrannosaurs were too big to capture small, nimble prey, such as furry mammals, birds, lizards, and little herbivorous dinosaurs like Parksosaurus.

Spinosaurs have teeth like those of big crocodiles and probably ate fish and ocean-going reptiles like sea-turtles. Even if spinosaurs and tyrannosaurs lived in the same spot, they would have eaten totally different food.

So, who is “dominant” depends on what sort of prey is being hunted.

3) How do we find out what a big predator ate and how it caught it’s food?

By careful comparison with the design of living animals and analysis of the habitat clues left in the rocks.

Example:  Tyrannosaurus rex.

Commonest prey animal in the same sediment: the duck-bill Edmontosaurus.

Could T. rex catch a duck-bill?  Some scientists say that T. rex was a stumble-bum, limited to a slow walk. They say that we could walk away from a charging T. rex.

Bio-mechanical test:  Among big animals today, faster animals have longer ankle bones (they’re called “metatarsals.”) Look at a lion and a cheetah. Both are cats. The cheetah is much faster. Check out the hind legs. Who has longer metatarsal ankle bones, compared to the thigh?

The cheetah does.

Now let’s compare a duck-bill with a T. rex. The hind legs are built to the same general bird-like plan. Who has longer metatarsal ankle bones?

The T. rex.  So we can conclude that a T. rex really could chase down a duckbill.

How could the duck-bill get away?  Here’s one theory: The abundance of turtle fossils, gators, crocs, and salamanders show that the habitat was warm, wet and supported dense thickets and woodlands.  A duck-bill didn’t have to run away. It could hide in tangled vegetation.