A wildlife biologist is using many techniques to find out how animals adapt to the cold.
Our Earth has unimaginable diversity, from seascapes 8,000 meters below the ocean’s surface to landscapes 8,000 meters above it. Its physical beauty comes in inconceivable living varieties. Some mammals lay eggs; some lizards are legless. Bats catch fish. Birds catch bats. Wood frogs in Alaska survive through winter even as two-thirds of their body tissues turn to ice.
But as climate alters habitats to which animals have spent thousands of years adapting, snow disappears more quickly now in some places and deepens in others. Receding sea ice strands polar bears on land and reduces the length of their hunting season. As permafrost at the bottom of Siberian lakes cracks, water drains into the ground; fish die.
My research focuses on conserving large species adapted to life in cold places, including the Northern Rockies, Central Asia and on permafrost in both Asia and Alaska. This winter, for the 11th straight year, I am returning to the Arctic. I want to understand how changing temperatures may be impacting muskoxen — animals that once roamed with extinct woolly mammoths.
To address this issue, I need to discern population trends and possible stressors, and to gain insights into these animals’ physiology, reproduction, predators and food sources. The overarching umbrella is a story of ice, snow and temperature.
Earlier this year scientists from NASA and the National Oceanic and Atmospheric Administration released a sobering finding: According to independent studies by both agencies, 2016 was the third year in a row to set a new record for global average surface temperatures. Warming patterns are most extreme in the polar regions, particularly in the Arctic.
One of the most striking trends we are observing in the Arctic is an increasing occurrence of winter days when temperatures never drop below freezing. Precipitation falls as rain, melting snow on the ground. This can be more serious than it sounds. In 2002 a winter rain-on-snow event on Canada’s Banks Island encased the ground in ice and prevented muskoxen from reaching their food supply. Some 20,000 animals died.
Cold-adapted species are feeling the heat. Moose experience more ticks, caribou more pathogens from the south. As northern vegetation grows more profuse, some species lose habitat. Red foxes displace Arctic foxes.
We know of the enormous changes in polar environments because of creative interdisciplinary collaborative studies by teams of scientists from dozens of countries. But at fine-scale levels, we know less about how these changes are affecting individuals, or how much flexibility many species have to adapt.
Research on American ice
Logistics related to traveling in the Arctic are significant year-round, and especially complex in winter. In Alaska I work with two assistants and we travel light. Typically, it is just Fred Goodhope Jr. (a Native Alaskan whose ancestors survived here for 12,000 years), a bio-technician, and me. Fred knows these lands like the back of his hands, whether he is fixing the throttle of a snow machine with dental floss at 10 degrees below zero or navigating ground blizzards without GPS.
Muskoxen occur in tightly knit herds, at times 50 kilometers apart. We navigate the tricky ice and tundra between the groups and gather data. For years my colleagues and I used helicopters to pursue, tranquilize and radio-collar muskoxen. This was a very useful way to garner biological insights, but I abandoned it five years ago because about 5 percent of the animals that we radio-collared failed to reconnect with their herds when the drugs wore off. Instead they sheltered alone in snow-holes for safety for up to two months.
I wanted more compassionate ways to collect data, so I continue to gather and analyze frozen poop sans radio-collaring. It contains iced hormones that we can assess to infer stress levels (gluco-corticosteroids) and pregnancy rates (progestagens). We know from these data that isolated females experienced stress levels three to six times greater than their companions back in the herd. The change to gentler tactics has been well worth it.