Robert Bakker: RAPTOR RED

The Early Cretaceous witnessed an escalation in brainpower among the carnivores. Raptor braincase bones were voluminous compared to the standards of Jurassic predators, and equally large-brained were the two other groups of carnivorous newcomers, the ostrich dinosaurs and the bantam-sized tro-odonts.

It was a time of ecological flux, when land bridges opened the gates to successive invasions from one region to another. The iguanodonts and gastons dug from the Black Hills in the Lakota beds match those from Utah very closely, and both sets of American dinosaurs are nearly identical to skeletons from the south of England. Such exact resemblances between America and Europe could only occur when a free and easy avenue of bio-geographical exchange had been opened between the two continents.

We will never know all the details of this grand intercontinental exchange of evolutionary products, but we can be sure that each dinosaur species that made passage across the Atlantic or Pacific carried with it a deadly cargo of viruses, bacteria, and parasites. Epidemiological warfare is a certainty whenever and wherever faunas mix across the world. In Wyoming today the threat of foreign disease is taken very seriously by my friends in the state fish and game commissions. Over the last few years, they’ve closed down several ranches that were breeding Asiatic deer because such exotic game can release pathogens that would devastate our native Wyoming deer and antelope.

We know that the life of dinosaurian hunters was hard. Most skeletons we excavate have clear marks of old wounds - broken and healed ribs, cracked limbs, and lower back vertebrae fused together by injury. To survive and raise their young, the predators needed more than sharp teeth and strong claws. They needed social bonds. How did Utahraptor choose their mates? How did they guide their offspring into adulthood? We do have clues.

Fossil trackways of acros found in Texas show them hunting in pairs, trailing herds of multi-ton astrodons, and it’s reasonable to suppose that these pairs represent mates working together. Since raptor brains were far larger for their body size than those of acros, we can surmise that the raptor society was more complex as well. I like to think that Utahraptor emotional ties between male and female, parent and young, were exceptionally strong and rich.

Three hours north of our Lakota quarries we have sites from the end of the Cretaceous, sixty-six million years ago, when that most famous of dinosaurs, T. rex, played the top predator role. The great ty-rannosaurs are cousins of the raptors, and the tyrannosaur data matrix helps us look into the mind of the raptor. My colleague from the Black Hills Institute, Pete Larson, has discovered a remarkable thing about the gender roles in rex. The biggest, most powerfully muscled specimens are female, as shown by the structure of the bones around the base of the tail.

Female dominance is a powerful piece of evidence that permits us to reconstruct the private lives of Cretaceous predatory dinosaurs. A family structure built around a large female is rare in meat-eating reptiles and mammals today, but it’s the rule for one category of predatory species -carnivorous birds. Owls, hawks and eagles have societies organized around female dominance, and we can think of tyrannosaurs and raptors as giant, ground-running eagles.

On late spring mornings, when the sun has just begun to warm the bedlands, I like to walk quietly along a line of twisted fenceposts, their barbed wire long ago fallen away into rusted uselessness. This is where I see the golden eagles. They perch on the tallest posts, facing east, with wings half open to catch the light. Usually the two of them are together, the female easily identified by her larger size. They’ve been together for five years. Lifelong monogamy is the rule for eagles.

The eagles watch me from a hundred yards away, but they seem to view me and all other humans with disdain. After their bodies have been warmed and the first thermal upwellings start to rise in the air, they take off and ascend in widening spirals.

They fly together and hunt together, and I’ve seen them feed their brood together at their nest on an isolated pinnacle of Lakota sandstone. I found the nest by accident one day when I was stooped over a string of eroded allosaur backbone in a gulley. My paleontological reverie was cut short when I saw huge shadows pass over the ground in front of me. I looked up and saw the female eagle’s face staring down from ten yards above.

She had the most amazing eyes, very clear and intelligent, and very fierce. When I imagine Raptor Red, she is looking at me with eyes like those.

THE END

Acknowledged as a rebel in his field, Dr Robert T. Bakker acted as an unofficial consultant for the special effects artists who created the dinosaurs for the film Jurassic Park. He is the dinosaur curator of the Tate Museum in Wyoming and the author of the groundbreaking nonfiction book The Dinosaur Heresies. He is most famous for proposing the stunning theory that dinosaurs weren’t cold-blooded, sluggish, solitary creatures we once imagined them to be, but were instead warm-blooded, active, and social animals. Thus he began a revolution that caused scientists to completely rethink their ideas about dinosaurs. He is considered to be one of the world’s foremost paleontologists.