Main description:

After travel through Alaska during the Second World War, in 1947 I went to Barrow with a very lively group of biologists. From their productive research developed the Arctic Research Laboratory. While we examined the rather surpris ingly modest metabolic rates of arctic warmblooded animals in cold, PER SCHO LANDER proposed and then carried out measurements of metabolism of some tropi cal animals in Panama. The differences could be formulated to show the basis of adaptation to arctic cold and to tropical warmth. Imagination and logic were required to formulate the comparison so that it could become a part of science, but the essential measurements were derived from animals and plants in their own arctic and tropical environments. Characteristics that adapt the forms of life to climatic conditions of various environments appear clear in the large dimensions of extremely differing climates. At the time of my arrival in Alaska many of the arctic Eskimos were still largely dependent on natural resources of their immediate and local environment, in which great seasonal changes in temperature and solar radiation appeared as dominant factors. The living environment on which they subsisted was also mar kedly affected by the changes of the seasons, in particular by the change in state of water to ice that terminated summer and by the melting that brought the late transition from winter to summer.

Contents:

1 Introduction.- 2 Environment of Arctic Life.- Geographical Characteristics.- Small Extent of Polar Regions.- Geographic Asymmetry between Arctic and Antarctic.- Eurasian and American Arctic Compared.- Arctic Seasons.- Isotherms: East-West Asymmetry.- Annual Solar Cycle.- Freezing and Prolongation of Winter.- Permafrost.- Spring Breakup.- Sea Ice.- Ice Caps and Glaciers.- Areas Occupied by Life.- Tundra.- Taiga.- Similarity in Circumpolar Arctic Conditions.- History of Arctic Climates.- Pleistocene Glaciation.- Land Bridge between Alaska and Siberia.- Refuges in Glacial Periods: Beringia.- Migrations of Man to America.- Early: Indians.- Eskimos.- Extinction of Large Land Mammals.- Adjustments of Climatic Change.- References.- 3 Mammals of the Arctic.- Palaearctic and Nearctic Regions.- Arctic Native Human Populations.- Russian Arctic Settlement.- Northern American People.- Arctic Mammals.- Polar Bears and Arctic Foxes.- Survey of Arctic Land Mammals.- Migrations by Arctic Land Mammals.- Sea Mammals.- Seals.- Numbers of Seals and Ice-breeding.- Ice-breeding Harbor Seals and White-coated Pups.- Gray Seals.- White-coated Pups of Other Arctic Seals.- Migrations of Arctic Seals.- Harbor, Ringed, and Bearded Seals.- Harp and Hooded Seals.- Walrus.- Whales.- Arctic Residents.- Migrants to Arctic Waters.- Arctic Mammals of the Late Pleistocene.- Resettlement of Lands as Wisconsin Ice Caps Melted.- Resettlement from Beringia.- Post-Wisconsin Invasion from a North Greenland Refuge.- Recapitulation of Views upon Post-Wisconsin Populations.- References.- 4 Arctic Land Birds and Their Migrations.- Birds Resident in High-arctic Latitudes.- Winter Birds of the Alaskan Tundra and Adjacent Forests.- Tundra.- Margin of Arctic Forest.- Survival in the Beringian Refuge.- Migrations of Birds.- Migrations to Arctic Alaskan Tundra.- Winter Residence Places of Arctic Migrants.- Migrations Along Western American Coasts to Nest on Interior Alaskan Tundra.- Migrations Overland in North America.- Oceanic and Asian Migrations to Alaska.- Migrations from Europe to Greenland.- Stability and Extent of Eskimo Knowledge of Birds.- Indications for Changes in Range of Birds.- Changes in Habits of Birds.- Wisconsin and Post-glacial Migrations.- Land Birds.- Maritime and Oceanic Birds.- Organization of Migrating Populations.- Sex and Age Organization of Willow Ptarmigan.- Central Point in Migration of Willow Ptarmigan.- Survey of Composition of Flocks.- Migrations in Other Parts of Alaska.- Organization of Migrating Lapland Longspurs.- Migration Over Approaches to Arctic Alaska.- References.- 5 Maintenance of Arctic Populations: Birds.- The Influx of Birds to Breed on Arctic Lands.- Some Common Limitations on Arctic Life.- Birds of the Interior Tundra.- Duration of Arrival.- Interval from Arrival to Nesting.- Number of Eggs Laid in a Clutch.- Duration and Warmth of Incubation.- Newly-hatched Young.- Success in Arctic Breeding.- Nesting in the High Arctic.- Birds of High-arctic Lands.- Colonial Maritime Birds.- Sea Birds that Nest in Arctic Colonies.- Nesting on Arctic Atlantic Shores.- Diversity in Schedules of Breeding.- References.- 6 Maintenance of Arctic Populations of Mammals.- Marine Mammals that Breed on Ice.- Seals and Walrus of Bering Sea.- Seasonal Conditions and Exposure of Pups.- Condition of Pups at Birth.- Development through Weaning.- Special Condition of Walrus Pups.- Geographical Variation in Development of Pups of Harbor Seals.- Mammals that Breed on Land.- Musk Oxen.- Reindeer and Caribou.- Caribou of Canada.- Caribou of Alaska.- Lemmings.- Distribution of Taxa.- Fecundity and Cyclic Variations in Numbers.- Explanation of Cyclic Variations in Numbers.- American Lemmings.- Lemmings at Baker Lake.- Lemmings at Barrow - 1949.- Lemmings at Barrow and Their Predators.- Periodic Southward Invasion by Snowy Owls.- Population Cycles and the Northern Catch of Furs.- Arctic Foxes.- Traditional Use of Dens and Distinction of Taxa.- Polar Bears.- Dens and Cubs.- Scope of Wandering by Bears.- References.- 7 Warm Temperature of Birds and Mammals.- Early Reports from Arctic Explorers.- Warmth of Arctic and Other Animals.- Arctic Mammals.- Birds.- Contrast of Environmental and Animal Warmth.- Variations in Temperature of the Body.- Birds.- Mammals.- Temperature of Sleeping Men.- Elevation of Temperature in Exercise.- General Observations on Temperature in the Body.- References.- 8 Maintenance of Warmth by Variable Insulation.- Insulation of Arctic Animals by Fur and Feathers.- Insulation of Tropical Mammals.- Size and Insulation.- Insulation of Birds.- Aquatic Birds and Mammals.- Formulation of Thermal Balance with Environmental Temperature.- Model of Heat Production by Regulated Warmth.- Maximum of Variable Insulation.- Formulation of Economy of Animal Heat.- References.- 9 Metabolic Supply of Heat.- Comparison of Specific Metabolic Rates.- Metabolic Rates of Northern and Tropical Mammals.- Metabolic Rates of Marine Mammals.- Basal Metabolism of Birds.- Human Basal Metabolic Production of Heat.- Adaptive Value of Basal Metabolic Production of Heat.- Lower Critical Temperatures of Mammals.- Variation in Critical Temperature.- A View of Behavior of Wild Mammals.- Heat of Small Mammals.- Lower Critical Temperatures of Some Tropical Mammals.- Lower Critical Temperature of Birds.- Effect of Wind.- Conversion of Food to Heat and Activity.- Daily Activity of Arctic Willow Ptarmigan.- Bioenergetics of Snowy Owls.- Summary.- Internal Temperature.- Basal Metabolic Production of Heat.- Resting Metabolic Production of Heat.- Metabolic Thermogenesis Induced by Cold.- Insulation.- References.- 10 Heterothermic Operation of Homeotherms.- Gradients of Temperature from Depth to Surface.- Bare Legs of Arctic Aquatic Birds.- Circulation through Cold Webbed Feet.- Vascular Heat Exchangers.- Adaptation of the Gull Foot for Cold.- Adaptation of Peripheral Nerve for Cold.- Thermal Gradients Over the Body.- Persistence of Cold in Extremities.- Heterothermic Operations in Mammals.- Feet of Porcupines and Dogs.- Extremities of Arctic Mammals.- Maintenance of Warmth in Feet Standing on Ice 143 Operation of Nerves in Heterothermic Mammalian Extremities.- Comparison of Homeothermic Internal and Heterothermic Peripheral Nerves.- Peripheral and Internal Nerves of Seals.- Reactivity of Heterothermic Arteries to Adrenaline.- Tolerance of Cold by Nerves.- Cellular Activity in Heterothermic Tissues.- Melting Points of Fats from Heterothermic Tissues.- Insulation of Mammals without Fur.- Adipose Tissues as Insulators.- Insulation of Swine.- Insulation of Seals by Heterothermic Tissues.- Thermal Gradients through Blubber.- Thermal Gradient in Flippers.- Topographic Variation in Surface Temperature.- Insulation of Polar Bears.- Seasonal Change of Insulation.- Thermoregulation in Walrus.- Thermoregulation in Whales.- Ontogeny of Effective Thermoregulation in Seals.- Size and the Use of Adipose Tissue for Insulation.- References.- 11 Size and Seasonal Change in Dimensions.- Temperature in Production of Heat.- Size of Animals and Their Economy of Heat.- Climatic Rules.- Seasonal Flexibility of Insulation.- Use of Posture to Vary Insulation.- Differences in the Distribution of Fur.- Small Mammals in Winter.- Weight and Stature of Arctic Willow Ptarmigan.- African and South American Large Mammals.- Size and Reserves of Heat and Energy.- Natural Fasting in Hibernation.- Fasting Periods in Normal Life Cycles.- Fasting by Mammals.- Seasonal Change in Myoglobin.- Ontogeny of Thermoregulation.- Birds.- Altricial Young Mammals.- Calves of Caribou.- Some Conclusions.- References.- 12 Insulation of Man.- Historical Use of Clothing.- Early Contact with Arctic Eskimos.- Shelter and Clothing of Eskimos.- Urban Man's Adjustment to Cold.- Adjustments of Men Native to Cold Climates.- Physiological Tests.- Warmth in a Cold Night.- Examples of Special Adjustment for Cold.- A Nepalese Pilgrim.- Immersion in Cold Water.- Swimmers Racing Across the English Channel.- Warm Hands of Arctic People.- True Tolerance of Cold Hands and Feet.- Comments on Insulation of Mammals without Fur.- References.