The Arctic is a region that’s gripped the attention of people living in a world that’s warming. The changing environment there raises crucial questions related to our survival: How are animals vulnerable to changes happening in their environment? What conditions do they need in order to successfully reproduce and live?
To answer those big-picture questions, scientists must delve into the details of how birds, fish and mammals are born, what they eat, how they choose mates and breed, where they range, when or if they return — the countless factors that determine whether creatures flourish or suffer.
UAA Professor Jennifer Burns chose long ago to study marine mammals — seals — but rather than journeying north from Anchorage to do her research, Burns travels 9,774 miles south, to Antarctica and approximately 2,000 Weddell seals that live in her study area 20 miles away from McMurdo Research Station.
“Up here in the Arctic, the species are harder to study logistically,” she explained. “We’re asking those types of questions with the population down there because they’re very easy to work with.”
Enhancing the quality of research
One reason Arctic seal species are hard to study? They’re skittish, because humans and polar bears hunt them.
“They see terrestrial things as a threat,” Burns said. “The seals in the Antarctic don’t have terrestrial predators in any shape — there are no polar bears in the Antarctic, despite what [a Coca-Cola ad] says. We can walk up to individual seals in that environment and they will not move away from us. It’s much easier to approach and find animals.”
Not only are Weddell seals docile, but Antarctica also provides an almost ideal in-the-wild research laboratory for Burns’ work.
In the Arctic, almost all the seals that reproduce on ice do so on pack ice, which is floating and mobile and unpredictable in its location. So where the seals are going to be, year in and year out, varies.
“They’re hard to find,” Burns said. “In Antarctica, we work on fast ice, which is ice that’s attached to land. Down there, it forms predictably every year — the seals are in pretty much exactly the same location every year — so we can find the same animals again and again within a season and we can find the same animals year to year across seasons.”
And, in Antarctica, a long-term tagging project has helped even more.
“Eighty percent of the animals down there carry flipper tags, little ID tags with a number on them,” Burns said.
What this means is that Burns and members of her research team — which includes Skyla Walcott, a UAA master’s student in biology; Amy Kirkham, a UAA/UAF Ph.D. student in fisheries; Roxanne Beltran, a UAA/UAF Ph.D. student in biology and wildlife; and Michelle Shero, a UAA postdoctoral researcher — can walk up to an animal and know who it is, know how old she is and how many pups she’s had rather than just randomly targeting individual seals.
“For this study, we’re looking for females of prime reproductive age, that we know can produce pups, that we know had a pup last year,” she said. “[Because of the tags,] we reduce the variability in our study so hopefully the variability we see is a result of important things related to our science questions.”
Burns says there’s another huge advantage to conducting research in an environment that holds a known population of a certain land mammal:
“It allows us to ask much more detailed, higher-resolution, more-refined questions than we could if we were just taking an icebreaker up into the Arctic and taking whatever seals we could get our hands on.”
The docile, predictable creatures of Antarctica
Antarctica is home to about 800,000 Weddell seals, which make the continent’s rim of “fast ice” their home. They’re named after James Weddell, a British sealing captain who, in the 1820s, led expeditions to a part of the Southern Ocean known as the Weddell Sea.
They’re big, 8.2 to 11 feet long, and burly, weighing between 880-1,360 pounds. Pups first swim at 1-2 weeks and are on their own as soon as they can hunt and accumulate enough fat to help them tolerate the frigid water. They’re mature at age 3 and can live up to 30 years. They can produce up to 49 different types of sounds.
Weddell seals lounge in small groups around cracks in the ice and stay in water to avoid blizzards, with only their heads poking through breathing holes in the ice. The chubby beasts feast on Antarctic cod, cephalopods, krill, fish and crustaceans; and, in the Antarctic winters, rely on their sense of touch from whiskers — sense organs with more than 500 nerve endings that enable seals to detect the wakes of swimming fish and capture prey.
The seals have no natural predators while they’re on fast ice, though killer whales and leopard seals are known to attack juveniles and pups at sea or on pack ice.
Seal research could save human lives
So why should nonscientists care about research in the Antarctic?
Understanding humans’ actual and potential impacts on the world is vitally important, so we can determine the best decisions to make about conserving and allocating its natural resources.
“I would love to think people value intact and healthy ecosystems, and I think a lot of us do, but we also need food resources and fishing and all the rest of it,” she said. “Figuring out how to minimize the negative consequences of what we’re doing is important, and to do that, we need to know how animals work in the environment.”
The big picture of the world’s impact on animals, fish, birds and insects is important, Burns said, but perhaps even more so is peering closely at the animals themselves — examining the infinitesimally small picture — in ways that could save or improve the lives of humans.
“A lot of wild animals that do really neat things physiologically have the potential to shed light on questions of medical importance,” Burns said. “They’re mammals, we’re mammals. There are some really interesting biomedical linkages when we start thinking about how some traits may be applicable to humans.”
At some points of the year, Weddell seals are almost 50 percent fat. They can gain or lose kilograms of body mass a day. How do they do that and stay healthy?
The seals can reach depths of close to 1,800 feet when they dive and forage in the wintertime, holding their breath for 20 minutes or more with no ill effects.
“How does their brain function with reduced blood flow?” Burns asked. “How are they able to shut off blood flow to keep working muscles or other tissues and then come back and breathe? A heart attack, essentially, is extremely reduced blood flow to the heart. Ischemia. When we have ischemia in our tissues, our kidneys, our liver, that causes cell death and damage. Seals do this repeatedly.”
Burns says it’s hard to make a “linear link” between seals and the development of, say, a drug that reduces the likelihood of heart attack, “but there are people who are working on the various steps along that pathway.”
One of Burns’ students is interested in another possible tangent of seal research.
“My postdoc’s very interested in whether we can figure out hormone receptors that are predictive of the probability of getting pregnant or not from an [in vitro fertilization] perspective,” she said, referring to Michelle Shero. “Human fertility is informing wildlife conservation, zoos’ captive-breeding programs. And some of the results coming out of captive-breeding programs are shedding light on things that might be useful within a human context — there’s cross talk back and forth.”
Written by Tracy Kalytiak, University of Alaska Anchorage