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Giraffes in a truck

Nature Accelerates

The giraffe and the pronghorn—genetic cousins—face pressure from humans and environmental changes. Will that stop two iconic species that have run for millennia?

The tallest mammal on Earth is vanishing. Giraffe populations in the wild have decreased by 30 percent in 30 years. Liza Dadone ’97 is part of an elite team that relocated them—to save them.

When loading an awake, agitated, lightly tranquilized giraffe, secure the ropes as brakes and guide the blindfolded ungulate onto the trailer.

Liza Dadone ’97 learned this singular rigging system firsthand, as one of a group of veterinarians working to save wild giraffes in Uganda by relocating them to safer habitats across the southern Victoria Nile.

“We’re trying to move the needle on critical conservation work to save these animals before it’s too late,” says Dadone, head veterinarian and vice president of mission & programs at the Cheyenne Mountain Zoo in Colorado Springs, Colo. “The question is, Can we do it fast enough?”

The Cheyenne Mountain Zoo, home to one of the largest captive giraffe herds in North America, has given Dadone an opportunity to fulfill a lifelong dream of working with wild animals. The zoo’s partnership with the Giraffe Conservation Foundation (GCF), a Namibia-based nonprofit working across Africa, is part of a global effort to save giraffes disappearing in the wild.

“Giraffe are my passion,” Dadone says. “So many species are disappearing at an alarming rate, and we need to up our game if we’re going to give them a chance.”

A curious, patterned periscope, the giraffe is one of the most iconic of all African wildlife. Long-lashed, rubbery-lipped, and seemingly unbothered by squabbles below its knobby-kneed radar, the majestic giraffe moves with a hypnotic, bounding grace. But threats to its survival continue, and are all directly related to human impact: loss of habitat, poaching, and sometimes trophy hunting.

“There is a real possibility that the giraffe could go extinct in our lifetimes, if we don’t start to act now,” says Stephanie Fennessey, director of GCF.

Dadone’s role in the Uganda transport of 37 giraffes involved careful darting, casting with ropes, and climbing onto each roughly 1-ton animal to prepare it for a journey across the river on a truck atop a ferry. The relocations, which began in 2015, and have continued in phases annually, are led by Uganda Wildlife Authority with funding and technical support from GCF, Cheyenne Mountain Zoo, and other organizations.

The first phase that Dadone helped with, in 2016, captured and released 18 giraffes successfully into historic habitat in Murchison Falls National Park, across the Nile River where giraffes had not lived in generations. The following year, Dadone helped the team capture and transport an additional 19 giraffes across the Nile to supplement the founding population. This population is now growing, with several new calves born—an early indicator of success.

In the past four years of reintroductions within Uganda, a total of 66 have been successfully rehomed to new habitats, or to supplement key populations. This ongoing work to restore giraffes to historic habitats in Uganda continues, with another reintroduction planned for late 2019.

“There were definitely moments when I thought I should be running the other way,” Dadone says about the intense experience. “The priority was ensuring patient safety and ensuring people safety. It was an amazing thing to watch and to be a part of.”

Even her queasiness as a teenager couldn’t keep Dadone from a career with animals. Working at a veterinary clinic in West Chester, Pa., she would stand in the doorway of the surgery room, slowly buckling at the knees at the sight of blood. She steeled herself, though, and ultimately outgrew it. At Swarthmore, she majored in biology. A comparative anatomy course convinced her that veterinary medicine was the route she wanted to take. Dadone graduated from the University of Pennsylvania School of Veterinary Medicine and then “got her foot in the door” in the zoo world.

“I loved it from the moment I got into it,” she says. A big part of her work is getting zoos more involved in impactful and relevant conservation efforts.

“Giraffe are not guaranteed a future,” says Dadone. “But there’s a huge reason for hope.”

Still, the task is daunting. According to GCF, in 2018, eight of the nine giraffe subspecies were placed on the International Union for Conservation of Nature’s Red List of Threatened Species. Two subspecies, the Kordofan and Nubian giraffe, are listed as critically endangered, while the reticulated giraffe is considered endangered. The Masai giraffe was added as endangered this year, Fennessey notes.

Additionally, the Thornicroft’s giraffe is listed as vulnerable, while the Angolan is under least concern. Both the West African and Rothschild’s giraffe were down-listed from endangered—to vulnerable and near threatened, respectively—due to targeted conservation efforts in their core habitats.

In Colorado, Dadone’s efforts with giraffes are aimed at preserving the species as well as helping develop medical advancements, such as improving giraffe neonatal care and stem cell therapy for geriatric giraffes. She plans to continue the work with wild giraffe relocation and conservation in Africa. Her role at the zoo is a critical way to hopefully ensure the future of this keystone species, she says. “They are one of the species people connect with the most,” she says. “They symbolize a view from above.”

She fondly recalls one of her first patients: a giraffe with whiplash—the result of an injury during a transport. “Zoos had started to rethink how we care for our animals,” says Dadone, who contacted a chiropractor who worked with horses. Knowing captive zoo giraffes were trainable with positive reinforcement, she worked with the zookeeper team to train the giraffe for physical therapy exercises. The giraffe soon learned to do neck stretches when cued, and would do multiple repetitions on each side daily in exchange for his favorite treats. The stretches worked: The neck injury healed.

“They are extremely intelligent,” she says, and they like to learn. “If you can train a giraffe to do yoga, what else could be possible?”



Earth’s second-fastest land mammal is on the move. John Byers ’70 chronicles their flight—and plight.

Some clues as to what may still haunt the collective subconscious of the pronghorn lay buried in Wyoming’s Natural Trap Cave.

There lay the fossilized remains of American cheetahs, an animal that once rocketed across grasslands in pursuit of prey. Beside them, the scattered bones of dispatched pronghorn.

Hunter and hunted, entombed in the Late Pleistocene after being caught unaware by a hidden cave mouth and a deadly drop. Those cave discoveries revealed, among many other evolutionary delights, that over the course of 10,000 years, the remarkable limbs of Earth’s second-fastest mammal have remained unchanged.

And though its ancient predators are long dead, the pronghorn is still running scared.

“It’s a breathtaking sight to see them run,” says zoologist and author John Byers ’70, who after 38 years of studying the pronghorn remains mesmerized.

Byers, who retired last year from the University of Idaho, has researched and written about their behavior on 

the National Bison Range in western Montana since 1981. His 2003 book Built for Speed is both a detailed story of his fieldwork and an ode to the animal that captured his attention and ran away with it.

Pronghorn are the sole survivor of a once-more-numerous mammal family, the Antilocapridae, he says. At the extinction event that ended the Pleistocene era, a dozen or so Antiocaprid species were decimated to a single survivor, Antilocapra americana, known colloquially as the American antelope. Why this species survived when all others went extinct remains a mystery. But one thing is certain: The animal’s ability to accelerate is a masterful adaptation.

In a sea of thundering hooves, glistening eyes, and compact frames, a running group of pronghorn is both sturdy and elegant. In flight a herd moves in collective shifts and straightaways, capable of reaching speeds of up to 60 mph. Their hooves fairly float above their shadows.

They can outrun a helicopter, but they don’t like to jump fences.

“I find almost everything about pronghorn interesting,” says Byers, who has embraced the gritty, demanding, and sometimes dangerous work of studying in the wilderness. “But I suppose that their most amazing talent is running. When a group is truly frightened, the individuals pack into a rather tight mass—like a school of fish, or a flock of starlings—that flows over the ground at startling velocity. Pronghorn have three high-speed gaits, but within a running group, there is almost perfect synchrony.”

Their ability to accelerate for several miles at 40 mph is biomechanics at work: “Individuals have the ability to transport prodigious amounts of oxygen to the muscles,” Byers says. The skeletal elements aid in speed, too. The pronghorn hand (its front foot) is a single shaft, about 9 inches long and the diameter of a human index finger.

Running speed is a consequence of two variables, says Byers: stride frequency (the number of times per second that a foot is moved forward) and stride length (the distance across the ground covered by each stride).

“Pronghorn stride frequency is about typical for mammals of this body mass,” or about three per second, he says, “but stride length is exceptional, mainly due to highly modified hands and feet.”

As expertly as they run, it’s no longer a necessity. Their closest threat, the coyote, couldn’t touch their top speeds.

“Pronghorn only needed to cooperate 10,000 years ago, when they were chased by nasty predators,” says Byers. “They don’t need to fight for anything now. In their day-to-day lives, they have no reason to run fast. But even with the pressure removed, pronghorn can’t get rid of that instinct.”

First described by explorers Lewis and Clark, and later celebrated in the classic folk song “Home on the Range,” the pronghorn’s range today extends from Canada through the United States and into northern Mexico.

Even without modern predators, new threats have emerged.

Climate change and increasing human activity, including fences built on migration routes, are putting pressure on the ungulates, a genetic cousin of the giraffe.

“Pronghorn did not evolve with fences and so cannot deal with them,” says Byers. Though they could easily jump over most fences, they avoid it whenever possible.

“I’ve seen them jump and land on their hind feet,” says Byers, who guesses that is their method of protecting damage to the long, delicate shaft bone in their front limbs. “The more you find out about them, the more you want to learn.”

They can also crawl under a fence that is built at least 18 inches off the ground, but landowners do not always follow this management recommendation.

“Fences built by cattle and sheep ranches in Wyoming have blocked historic migration routes and killed many pronghorn,” says Byers. “With climate change, pronghorn populations will shift to the north. The southernmost populations, in Arizona and northern Mexico, will likely become extinct.”

Byers’s interest in studying social development in a species of intermediate sociality initially drew him to the pronghorn. The species’ emotional distance seemed appropriate, he thought.

“Adult pronghorn dislike each other and form groups only because they have to,” says Byers. National Bison Range offered him a chance to observe up close the one instance in which they do bond—as mothers and fawns. “There is no bonding between the adults. But the mother contributes everything to the fawns.”

There is so much still to learn, says Byers. Reflecting on his research (shared in three books and 70 journal articles), he says he is most pleased that he was able to prove that pronghorn females, in an exacting and sometimes comical process, actively shop for and choose mates.

They pay a high energy cost to do so, he says, and that mostly converges in their choice on a population subset 

of males that have high values of what biologists call “breeding value for offspring performance.”

Seeing the male’s vigor, a female is willing to mate with him. Byers has watched a male defend his harem from incoming males for half a day without rest. The females encourage—and watch for—that stamina and strength.

The most frequently chosen males sire offspring with higher growth rates and higher probabilities of survival, Byers says. Now, he hopes to test his hypothesis that these chosen males are genetically different from the males that females reject.

“Once you get to know an animal well for a while, you know them as individuals,” he says. “Because they really are individuals.”

Mating theatrics aside, life for the pronghorn is often brutal. Between 150 and 200 pronghorn fawns are born on the National Bison Range each spring. Some years, though, none of them makes it into adulthood. The number of those that live to weaning in late August has hovered at 5 percent over the past decade.

“Pronghorn seem to be kind of grim most of the time,” says Byers. “Every instant of their life is work to survive.”

His career has allowed him to reap the wonders of observation, and even the thrill of escape. Once while observing a pronghorn mother in Yellowstone, Byers noticed that something was “freaking her out.” Moments later, a huge male grizzly came into view. The bear did not veer off and instead came directly toward him.

“It was simultaneously beautiful and really scary,” says Byers, who, unlike the pronghorn, did not run. Instead, he relied on his training, avoided eye contact with the bear, and ultimately walked (briskly) back to his truck.

“Spending thousands of hours in the field allows one to see many incredible events,” says Byers, now working on a campaign to create Great Plains National Park. “You never know when you’ll see one, but if you are out for long enough, these events will unfold before you.”