Ethology and Behavioral Ecology of Sea Otters and Polar Bears

Description

Sea otters and polar bears are carnivorous marine mammals that still resemble their terrestrial ancestors. Compared with Cetacea (whales and dolphins), Sirenia (dugongs and manatees), and Pinnipedia (seals, sea lions, and walrus), they are less adapted for an aquatic life and the most recently evolved among marine mammals. Sea otters are amphibious but seldom come ashore, and polar bears primarily occur on sea ice or along the shore. When at sea, both species spend most of their time swimming at the surface or making short, shallow dives when foraging or pursuing prey. Indeed, polar bears rarely pursue seals in water. Nevertheless, polar bears are powerful swimmers and will stalk seals from the water. As with many other large carnivores, they are solitary hunters. Although sea otters are gregarious and form aggregations at sea called rafts, they are primarily asocial. Except during mating, the principal interaction among sea otters occurs between a female and offspring during the six-month dependency period. In large carnivores (e.g., wolves and lions) that feed on ungulates, sociality and cooperation are favored because of the need to capture large prey and defend carcasses. Polar bears, which are the largest terrestrial carnivore, are solitary hunters of seals and are neither gregarious nor social. Males and females briefly associate during courtship and mating. During this time, males aggressively compete for females. At other times, males generally avoid each other except for aggregations of males that form while summering on land, and females with cubs avoid males, which are known for infanticide. As with sea otters, the interaction of polar bears outside of mating occurs between a female and her offspring during the 2-3 year dependency period. This interaction is critically important when altricial cubs are born in the winter den. This book provides new insight into the ethology and behavioral ecology of sea otters and polar bears. Each chapter reviews the discoveries of previous studies and integrates recent research using new techniques and technology. The authors also address historic and current anthropogenic challenges for their survival as climate change alters entire marine ecosystems. Introduction to the Series Preface Contents Chapter 1: Introduction 1.1 The Behavior of Sea Otters and Polar Bears in the Marine Environment 1.2 Chapter Sequence References Part I: Ethology and Behavioral Ecology of Sea Otters Chapter 2: Taxonomy and Evolution of Sea Otters 2.1 Taxonomy 2.2 Early Evolution of Mammals 2.3 Emergence of the Carnivora 2.4 Mustelidae and the Otter Clade 2.5 Sea Otters References Chapter 3: Sea Otter Behavior: Morphologic, Physiologic, and Sensory Adaptations 3.1 Morphology 3.1.1 Craniodental Morphology and Feeding 3.1.2 Axial and Appendicular Skeletal Morphology, Prey Capture, and Locomotion 3.1.2.1 Axial Specialization 3.1.2.2 Appendicular Specialization 3.1.2.3 Aquatic Locomotion 3.1.2.4 Terrestrial Locomotion 3.2 Physiology 3.2.1 Respiration, Lung Volume, Buoyancy, and Oxygen Stores 3.2.2 Effects of Pressure 3.2.3 Adaptations for Breath-Hold Diving 3.2.4 Metabolism and Thermoregulation 3.2.5 Sleep 3.3 Sensory Systems 3.3.1 Vision 3.3.2 Audition and Sound Production 3.3.3 Sense of Touch and Vibrissae 3.3.4 Olfaction (Smell) 3.3.5 Gustation (Taste) 3.3.6 The Multimodal Sensory Perception (Umwelt) of Sea Otters References Chapter 4: Sea Otter Foraging Behavior 4.1 Sea Otters: Marine Specialists But Diet Generalists 4.2 Evolution of Sea Otter Foraging Behavior 4.3 Foraging Dives 4.4 Diet 4.5 Prey Capture 4.6 Daily Foraging Duration 4.7 Carrying Capacity and Foraging Behavior References Chapter 5: Social Structure of Marine Otters: Inter and Intraspecific Variation 5.1 Patterns of Social Behavior and Cooperation in Otters 5.2 Marine Otters 5.3 North American River Otter Sociality 5.3.1 Social Interactions Among Males 5.3.2 Social Interactions Among Females 5.3.3 The Role of Latrines in River Otter Sociality 5.3.4 Social Behavior at Latrines 5.3.5 River Otter Social Network Structure 5.4 Sea Otter Sociality 5.4.1 Interactions Among Males 5.4.2 Interactions Among Females 5.4.3 Sea Otter Social Structure 5.5 Conclusions and Future Directions References Chapter 6: Reproductive Behavior of Male Sea Otters 6.1 Male Sea Otters: Morphologic, Physiologic and Behavioral Traits 6.2 Anatomy and Physiology of Male Reproduction 6.3 Evolution of the Sea Otter Mating System 6.4 Male Territorial Behavior 6.5 Male Mating Behavior 6.6 Comparisons with Other Marine Mammals and Otters 6.7 Conclusions References Chapter 7: Reproductive Behavior of Female Sea Otters and Their Pups 7.1 Female Sea Otters: Morphologic, Physiologic, and Behavioral Traits 7.2 Anatomy, Physiology, and Behavior of Female Reproduction 7.3 Lactation 7.4 Maternal and Pup Behavior 7.5 Female Reproductive Strategy 7.6 Conclusions References Chapter 8: Sea Otter Behavior and Its Influence on Littoral Community Structure 8.1 Sea Otters: A Littoral Predator 8.2 The Challenge of Sea Otter Ecological Research 8.3 Historical Perspective 8.4 Current Perspective 8.5 Community Changes in Nearshore Marine Ecosystems 8.5.1 Top-Down Effects 8.5.2 Bottom-Up Effects 8.5.3 Indirect Effects 8.6 Contrasting Littoral Communities Along the Gulf of Alaska 8.7 Future Directions References Chapter 9: Sea Otter Predator Avoidance Behavior 9.1 The Sea Otter Predator-Prey Relationship 9.2 Humans 9.3 Bald Eagles 9.4 Brown Bears 9.5 White Sharks 9.6 Killer Whales 9.7 Conclusions References Chapter 10: Sea Otters and the Maritime Fur Trade 10.1 Native Uses of Sea Otters 10.2 The Early Asian Sea Otter Trade 10.3 Bering´s Expedition Discovers Sea Otters 10.4 The Rush for Sea Otter Fur Begins 10.5 Conquest of the Aleutian Islands 10.6 The Russian Invasion of Alaska´s Southcentral Coast 10.7 Sea Otter Hunting Techniques 10.8 The Sea Otter Fur Trade in the Early nineteenth Century 10.9 The Sea Otter Fur Trade from 1820-1840 10.10 Purchase of Alaska by the United States and Renewed Sea Otter Hunting 10.11 Effects on Sea Otter Populations 10.12 Effects on Native Hunters 10.13 Effects on Natives Left Behind 10.14 Effects on Colonial Russians 10.15 The Economics of the Maritime Sea Otter Trade 10.16 Lessons from the Sea Otter Fur Trade References Part II: Ethology and Behavioral Ecology of Polar Bears Chapter 11: Polar Bear Taxonomy and Evolution 11.1 Taxonomy 11.2 Polar Bear and Brown Bear Pre-genetic and Genetic Studies 11.2.1 Pre-genetic Studies 11.2.2 Genetic Studies 11.2.3 Ancient DNA 11.2.4 Current Hypotheses 11.3 Polar Bear Diversity 11.4 Polar Bear Hybridization with Brown Bears 11.5 Natural Selection 11.6 Future Directions References Chapter 12: Polar Bear Behavior: Morphologic and Physiologic Adaptations 12.1 Introduction 12.2 Morphology 12.2.1 Temporal and Spatial Variation in Morphometrics 12.2.2 Craniodental Morphology and Feeding 12.2.3 Axial and Appendicular Skeletal Morphology 12.2.4 Body Composition 12.3 Senses 12.4 Metabolism 12.5 Thermoregulation 12.6 Reproduction and Hibernation 12.7 Feeding and Fasting 12.8 Disease and Immune Function 12.9 Physiological Effects of Environmental Contaminants 12.10 Future Research References Chapter 13: Polar Bear Foraging Behavior 13.1 Introduction 13.2 Seasonal Foraging Patterns 13.3 Hunting Behavior 13.4 Learning to Hunt 13.5 Terrestrial Foraging 13.6 Future Research 13.7 Conclusions References Chapter 14: Polar Bear Reproductive and Denning Behavior 14.1 Introduction 14.2 Reproduction 14.2.1 The Mating System 14.2.2 The Reproductive Cycle 14.2.3 The Role of Adult Males in the Reproductive Cycle 14.2.4 The Role of Adult Females in the Reproductive Cycle 14.2.5 The Role of Polar Bear Cubs in the Reproductive Cycle. 14.3 Denning 14.3.1 Denning Ecology 14.3.2 Distribution of Denning Sites 14.3.3 Den Structure 14.3.4 Den Site Fidelity 14.3.5 Denning Chronology 14.3.6 Post-denning Behavior 14.3.7 Response to Human Activity at Maternal Den Sites 14.4 The Effect of Climate Change on Reproduction 14.5 Future Research References Chapter 15: Polar Bear Maternal Care, Neonatal Development, and Social Behavior 15.1 Introduction 15.2 Maternal Behavior and Neonatal Development 15.2.1 Gestation and Altriciality 15.2.2 Maternal Behavior 15.2.3 Neonatal Behavior 15.3 Social Behavior 15.4 Effects of Climate Change on Neonatal Behavior and Development 15.5 Conclusions and Future Research References Chapter 16: Polar Bear Behavior in Response to Climate Change 16.1 Changes in Feeding Behavior 16.2 Movements and Habitat Use 16.3 Denning 16.4 Weaning 16.5 Mating 16.6 Conclusions References Chapter 17: Human-Polar Bear Interactions 17.1 Human-Wildlife Interactions 17.1.1 Interactions and Conflict: Key Terms and Definitions 17.1.2 Behavioral Components of Conflict: A Bear´s Perspective 17.1.3 Behavioral Components of Conflict: A Human Perspective 17.2 Historical Drivers of Human-Polar Bear Interactions and Conflict 17.2.1 Subsistence Hunting and Arctic Exploration 17.2.2 Human Population Growth 17.2.3 Attractants 17.2.4 Recreation 17.2.5 Industrial Development 17.3 Contemporary Drivers of Human-Polar Bear Interactions and Conflict 17.3.1 Climate Warming 17.3.2 Attractants Revisited 17.3.3 Tourism and Recreation 17.3.4 Oil and Gas Exploration and Production 17.4 Mitigating the Risk of Future Conflict: A Conceptual Model References Index