Photos by Moffat Photography
It’s midnight, and a small wooden boat glides silently through the reeds along the Peruvian shore of Lake Titicaca. A man from the Uros tribe, which inhabits a nearby cluster of floating islands, expertly manoeuvers the boat with a long pole. His son perches on the bow brandishing a small hand net and flashlight, peering ahead at a duck with a speckled breast and bright blue bill. As the boat drifts to within arm’s reach, the boy swipes the net down and traps the bird, yanking it into the boat. Their quarry tonight is the Puna teal, yet this father-son team is not hunting dinner. Their efforts are a vital part of UBC zoologist Bill Milsom’s latest project.
The Puna teal is common here, and outwardly there’s nothing unusual about it. Yet to Milsom, a comparative physiologist, the bird is intriguing. He is here to study five species of duck and their unique adaptations to altitude. Lake Titicaca is nearly 4,000 metres above sea level, where oxygen levels drop to about 65 per cent. Visitors can expect to experience a few days of headaches, difficulty sleeping, and shortness of breath. But the birds don’t seem to notice. They fly, paddle, and dive effortlessly, when a short flight of stairs leaves their human observers breathless and dizzy. This discrepancy fascinates Milsom. “The big question,” he says, “is how do they do it?”
The team has assembled a lab in a hotel on the shores of the lake. Large cylindrical gas tanks, flow meters, and pressure transducers are primed, and the captured duck sits in a small chamber, hooked up to a heart rate monitor and gas analyzer. The researchers experimentally decrease the oxygen levels in the chamber and measure cardiorespiratory responses – or the degree to which the bird increases its breathing and heart rate to overcome the effects of less oxygen. They take a small blood sample to measure the oxygen-binding capacity of the duck’s hemoglobin, and also measure the volume of its lungs.
How do lizards, amphibians, and fish cope with rivers that undergo massive seasonal variation?
Milsom has spent the best part of five decades studying the cardiovascular and respiratory adaptations that allow species to live in a variety of unusual and extreme environments. How do lizards, amphibians, and fish cope with rivers that undergo massive seasonal variation, for instance – from floods in the wet season, to drought in the dry season? And as global warming increases the temperature and acidity of rivers, how are the resident fish affected and how well can they adapt to the changes?
Milsom has attempted to answer questions like these since his first expedition as a graduate student. He was a late addition on a trip to the Antarctic to study giant albatrosses and penguins for a project that adorned the cover of the November 1971 issue of National Geographic. He’s been travelling to the habitats of his research subjects ever since. His interest in altitude led to his highly acclaimed work on bar-headed geese. Two weeks before arriving at Lake Titicaca, he was on the Mongolian grasslands catching bar-headed geese, working from a makeshift lab in a yurt. These birds perform an extraordinary migration over the Himalayas. Using radio telemetry devices to track them, the researchers found that some geese soared as high as 7,000 metres, and they have spent years studying the remarkable adaptations to the wing shape and respiratory responses needed to undertake such a taxing migration. He also studies these geese at Lake Qinghai in China. Otherwise, look for Milsom in Brazil in the Amazonian city of Manaus or on the Pantanal River, studying caimans, pit vipers, rattlesnakes, turtles, anacondas, boas, pythons, tortoises, tegu lizards, and various fish. He also has ongoing projects in the Peruvian Andes with Andean geese and crested ducks. Closer to home, he is studying how Okanagan squirrels change their respiratory patterns to cope with hypothermia during hibernation. His chosen field is not without its hazards. “One of the challenges of being a respiratory biologist is that you’re constantly putting your hands in animal’s mouths and working around the nasty bits,” says Milsom. “Over the years, I’ve probably been bitten by almost everything I’ve ever worked on.”
Climate change may force tropical species to seek cooler temperatures, possibly by heading to higher elevations. But how will they fare with less oxygen?
Milsom recently stepped down as head of Zoology at UBC and is approaching retirement. However, this is unlikely to be his last trip to Peru. He sits back on a cement pier jutting out into Lake Titicaca, looking across the bay at the town of Puno. The hum of boat traffic drifts across the water while countless birds flit in and out of the reeds. “Most of us are driven by curiosity and we do curiosity-based, discovery research,” says Milsom, reflecting on his life’s work. “Of course, you’d like to think that there is going to be application of what you do.” Climate change may force tropical species to seek cooler temperatures, possibly by heading to higher elevations. But how will they fare with less oxygen? How will fish and amphibians cope with warming water, or rising carbon dioxide or acidity? “A lot of that depends on us knowing how much plasticity there is within a species,” Milsom says. “Which are the ones that can adapt? Which are the ones that can’t?” Since he studies animals that have evolved to cope with low oxygen environments, his findings could also shed light on asthma and emphysema, diseases characterized by oxygen limitation. However, Milsom maintains that the factors leading to important discoveries can be unpredictable. "Basic research should be supported for no other reason than that it provides a knowledge base so that things can be applied later," he says.
The easy-going atmosphere in the lab in Peru is a testament to the importance Milsom puts on relationships – with colleagues and students, and with the local people for their expertise in where to find the animals and how to capture them. “The most rapid advances in science are multi-disciplinary and come from collaborations. We bring expertise together,” he says. For this project alone, Milsom’s collaborators include his former UBC doctoral student and now associate professor at McMaster, Dr. Graham Scott, as well as colleagues and students from Florida, Alaska, Australia, Peru, and Colombia. They each tackle the question of adaptation from a different angle – from a molecular and evolutionary perspective, to pulmonary mechanics and ventilation.
Even nearing the end of a long and distinguished career, Milsom talks excitedly about the results of each project. Whether he’s describing how the wing shape of the bar-headed goose affects its trans-Himalayan migration, or discussing the tracheal volume of high altitude ruddy ducks, his curiosity and passion never wane. When asked what has mattered most to him in his career, after years of research, and dozens of expeditions to far-flung parts of the world, he pauses, then smiles. “It’s the pleasure of the places we’ve been,” he says simply, “and the experiences we’ve had.”