Earth_Magazine_October_2017

T. rex and is really beat up, so people
thought she could be anywhere from 100
to 200 years old. I was stunned to find she
was so young. I often say T. rex was the
James Dean of dinosaurs; they lived fast
and died young.

BA: You’ve been involved in a lot of
documentaries and even hosted some
shows. How did that begin?
GE: When I was getting settled as a
new professor, around 2000, I got a call
from a producer at National Geographic
who told me they were working on a film
about a 110-million-year-old crocodile,
called SuperCroc (Sarcosuchus impera-
tor), the largest member of the crocodile
family. They had a lot of footage of the
scientist digging up the skeleton, but
needed more material for the two-hour
special. The producer asked if I could
figure out how to estimate the bite force,
which had never been done before. I
said, “Yes, and the way to do it would be
through the testing of bite forces in living
crocodilians.” But I told them I couldn’t do
it. I was a new professor and didn’t want
to appear like I wasn’t serious about get-
ting tenure by running off and doing this
“cowboy science.” I also mentioned that I
didn’t have a grant, which is required to
advance in academia. The producer told
me that National Geographic has grants
[available]. I received the one-page appli-
cation, submitted it, and heard back in a
day that it was approved. My first grant
— I wish they all were so easy!
I did the research, and after that film,
another producer from National Geo-
graphic called me up, said she liked what I

said and how I said it, and asked if I would

host “Hunter & Hunted.” I was able to

travel to exotic places like Komodo Island

and Kodiak Island. It was really exciting.

Since then, I’ve done about 135 films.

I never expected TV to be part of my

career. And I have to admit, when I first did

the show, I didn’t tell any colleagues. I was

flying up to D.C. on weekends to film the

episodes. I was worried about tenure, and

also what my professional colleagues would

think about me being a TV presenter. Actu-

ally, a number have talked to me about it

since, and said they wish there were more

professional voices for science on TV.

BA: How do you determine the bite

force of an extinct giant crocodile?

GE: For that work, I teamed up with

engineering colleagues to design bite force

meters specifically for use on crocodilians.

Unfortunately, we had only six weeks to

get them ready for the film, so the race

was on! We first tested a growth series

of alligators at the St. Augustine Alligator

Farm Zoological Park, lassoing them, and

holding or strapping them down. They

were more than happy to crush down on

the meter. We recorded a 964-kilogram

bite force for a large adult alligator —

the highest bite force ever measured in

an animal at that time. We then caught

wild alligators to compare them to captive

ones, and found they have the same bite

force. That gave me a green light to use

captive animals as models for [species’

behavior] in the wild. When I wanted to

do other species of crocodilian, my team

went to Australia and tested some 5-meter

crocodiles and got a world-record bite

force of 1,678 kilograms. Ultimately, we

determined that the SuperCroc had a bite

force of about 8,165 kilograms. That’s like

setting a semi-trailer truck on top of those

jaws — crazy.

BA: What are you working on now?

GE: I’m co-director of the Arctic Pale-

ontological Research Consortium with Pat

Druckenmiller, curator of earth science at

the University of Alaska’s Museum of the

North in Fairbanks. We’re trying to unlock

the mystery of how dinosaurs lived at high

latitudes. Although the world was warmer

then, there still would’ve been five to six

months of complete darkness and it would

have snowed on them. In Alaska today,

it’s rainy and cold, and the bones we find

in the Arctic are actually in permafrost.

It is rough fieldwork. So, just like we are

dealing with rough conditions up there,

so were the dinosaurs.

It’s like a lost world in the Arctic —

almost every dinosaur [we find] is a new

species. We put out a theory a few years

ago that the Arctic dinosaurs were a cold-

adapted group and that’s why they are all

different from other parts of the conti-

nent. We never find turtles or crocodiles

— no ectotherms. This supports the idea

of dinosaur warm-bloodedness. No one

realized there was a cold-adapted fauna

of dinosaurs, and that’s really exciting.

Also, we recently began exploring

Denali National Park. Last year, we found

thousands of dinosaur tracks, includ-

ing from raptors. We also found the

first dinosaur bones in the park. We’re

trying to learn more about the popula-

tion biology.

BA: What are some of the big unan-

swered questions in dinosaur biology?

GE: We’ve been stymied trying to fig-

ure out how to sex dinosaurs because we

can’t do it from just looking at skeletons.

There have been a few theories that didn’t

pan out or are still on trial. A few years

ago, a paper came out saying you could

look at the tailbone to determine sex,

which would be shorter in females rela-

tive to males, so she could pass the eggs.

But I did a study with alligators, showing

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