Ethology and Behavioral Ecology of Phocids (Ethology and Behavioral Ecology of Marine Mammals)

Phocid (or earless or true) seals are ecologically diverse, occupying habitats from the tropics to the poles in marine and freshwater and feeding on anything from tiny zooplankton to other marine mammals. There are 18 species of phocid seals, the smallest species (ringed seal) is more than 20 times smaller than the largest (southern elephant seal), with marked sexual dimorphism present in some species. This book examines the behavior, ecology, and physiology that allow phocid seals to inhabit such a wide range of habitats. The book is composed of 16 chapters written by 37 authors from 8 countries. The book first describes the general patterns of phocid behavior, followed by descriptions of what is known about well-studied species. We have taken a holistic approach, focusing not only on the behaviors themselves but also on the factors that constrain the expression of behavior and the proximate mechanisms driving behavior. In many cases, the chapters represent collaborations between well-established researchers and early-mid career individuals who bring new perspectives to help carry the field of phocid behavioral ecology well into the future. Remembering and Celebrating Bernie McConnell by Mike Fedak Preface Introduction to the Series Contents Part I Patterns of Phocid Ethology and Behavioral Ecology 1 The Origin of Phocid Seals and Evolution of Key Behavioral Character Traits 1.1 Introduction 1.2 Origin and Affinities 1.3 Evolution and Biogeography 1.3.1 Stem Monachines 1.3.2 Monk Seals (Monachini) and Elephant Seals (Miroungini) 1.3.3 Antarctic Seals (Lobodontini) and Southern Hemisphere Monachines 1.3.4 Fossil Phocines 1.3.5 Crown Phocines 1.4 Functional Anatomy 1.4.1 Size and Sexual Dimorphism 1.4.2 Sensory Abilities 1.4.3 Feeding 1.4.4 Locomotion and Diving Abilities 1.5 Diversity Changes Through Time 1.6 Conclusions References 2 Phocid Sensory Systems and Cognition 2.1 Introduction 2.2 The Visual System 2.2.1 Sensitivity—Adaptations to Dim Light Vision and Spectral Sensitivity 2.2.2 Resolution—Light-Focusing Apparatus and Retinal Adaptations 2.2.3 Visual Neuroanatomy 2.2.4 Motion Vision and Other Functions of Vision 2.3 Mechanoreception 2.3.1 General Aspects of the Vibrissae 2.3.2 Vibrissa Types 2.3.3 Follicle Sinus Complex 2.3.4 Functions of the Vibrissal System 2.4 Audition 2.4.1 Ear Anatomy 2.4.2 Sound Transmission 2.4.3 Sound Localization 2.4.4 Hearing Sensitivity 2.4.5 Function of Audition 2.5 Chemoreception 2.5.1 Olfaction 2.5.2 Gustation 2.6 Other Senses 2.6.1 Unconfirmed Magnetoreception 2.6.2 Perception of Time 2.7 Cognition 2.7.1 Reversal Learning 2.7.2 Concept Formation 2.7.3 Concluding Remarks on Phocid Cognition 2.8 Summary References 3 Social Communication in Phocids 3.1 Introduction 3.2 Vocal Communication 3.2.1 Females and Pups 3.2.2 Adult Males 3.3 Visual Communication 3.3.1 Visual Acuity 3.4 Olfactory Communication 3.4.1 Mother–Pup Interactions 3.4.2 Males 3.5 Conclusions References 4 Physiological Capacity and Constraint Impact Behavioral Phenotype in Phocid Seals 4.1 Physiological Capacities and Constraints 4.2 Diving Physiology 4.2.1 The Pressure Problem 4.2.2 The Oxygen Problem—Breath-Hold Diving 4.3 Fasting Physiology 4.4 Thermoregulation 4.5 Behavioral Endocrinology 4.5.1 Metabolism 4.5.2 Reproductive Endocrinology 4.5.3 Stress Hormones 4.6 Future Directions References 5 Habitat Utilization and Behavior of Phocid Seals in Relation to Oceanography 5.1 Introduction 5.2 Worldwide Distribution of Phocid Seals 5.2.1 Low Latitude Seals 5.2.2 Subtropical and Mid-Latitude Seals 5.2.3 Subpolar Seals 5.2.4 Polar Seals 5.2.5 Non-marine Seals 5.3 Biologging 5.3.1 The Relationship Between Seals and Their Environment 5.3.2 Statistical Approaches for Modeling Relationships Between Movement and Environment 5.3.3 Seals as Oceanographic Samplers 5.4 Effects of Environmental Characteristics on Habitat Use 5.4.1 Wind and Surface Currents 5.4.2 Fronts 5.4.3 Mesoscale and Sub-mesoscale Features 5.4.4 Productivity 5.4.5 Temperature 5.4.6 Bathymetry and Ocean Floor Characteristics 5.4.7 Ice 5.5 Concluding Remarks References 6 Foraging Ecology and Behavior 6.1 Introduction 6.2 Statistical Approaches for Inferring Foraging Behavior 6.2.1 Foraging Inferred from Horizontal Location Data 6.2.2 Foraging Inferred from Dive Data 6.2.3 Inference of Foraging Success 6.3 Foraging Behavior 6.3.1 Spatial and Temporal Scales of Foraging 6.3.2 Intrinsic Factors 6.3.3 Extrinsic Factors 6.4 Life History Consequences 6.5 Conclusions References 7 Breeding Behavior 7.1 Introduction 7.2 Male Breeding Behavior 7.2.1 Mating Systems 7.2.2 Mating Strategies 7.2.3 Breeding Displays 7.2.4 Interactions on the Breeding Colony 7.3 Female Breeding Behavior 7.3.1 Synchronicity of Pupping and Estrus 7.3.2 Pupping Site Selection 7.3.3 Birth and the Dependent Period 7.3.4 Interactions on the Breeding Colony 7.3.5 Lactation Duration and Weaning 7.4 Pup Behavior 7.4.1 Behaviors During the Dependent Period 7.4.2 Weaning and Post-Weaning Fasts 7.5 Future Directions References 8 Reproductive Energetics of Phocids 8.1 Introduction 8.2 The Capital–Income Continuum 8.3 Habitat and Breeding Systems: Environmental Potential for Polygyny 8.3.1 Land-Breeding Seals 8.3.2 Ice-Breeding Seals 8.4 Energy Acquisition and Expenditure Relative to Reproductive Patterns 8.4.1 Energy Allocation to Growth and Reproduction 8.4.2 Milk Production and Lactation Duration 8.4.3 Body Size and Maternal Resources: The Role of Maternal Overhead 8.5 Constraints on Body Size 8.6 Foraging and Reproduction: An Economical Lifestyle 8.7 Male Reproductive Energetics 8.8 Origins and Evolutionary Implications 8.9 Future Directions for Research References Part II Examples of Phocid Ethology and Behavioral Ecology: Insights from Data-Rich Species 9 The Gray Seal: 80 Years of Insight into Intrinsic and Extrinsic Drivers of Phocid Behavior 9.1 Introduction 9.2 History 9.3 Interactions on Land: The Breeding Season 9.3.1 Interactions Among Males 9.3.2 Interactions Between Males and Females 9.3.3 Interactions Between Females and Their Pups 9.3.4 Interactions Between Females 9.3.5 Interactions Between Pups 9.3.6 Interactions with the Physical Environment 9.4 Interactions at Sea 9.5 Personality 9.6 Ontogeny of Behavior 9.7 Novel Observations and Emergent Behaviors 9.8 Future Directions References 10 The Harbor Seal: The Most Ubiquitous Phocid in the Northern Hemisphere 10.1 Introduction 10.2 Haulout Behavior 10.3 Reproductive Behavior 10.3.1 Male Reproductive Behavior 10.3.2 Female Reproductive Behavior 10.4 Foraging Behavior 10.4.1 Diving Behavior and Physiology—Seasonal and Diurnal Changes 10.4.2 Diet and Habitat Preferences 10.4.3 Prey Detection and Capture 10.5 Movements 10.5.1 Large- and Small-Scale Adult Movement 10.5.2 Movement of Weaned Pups and Juveniles 10.5.3 Modeling Movement and Distribution of Seals 10.6 Anthropogenic Impacts 10.7 Final Thoughts References 11 The Elephant Seal: Linking Phenotypic Variation with Behavior and Fitness in a Sexually Dimorphic Phocid 11.1 Introduction 11.1.1 History and Progress of Behavioral Ecology Research 11.1.2 Exploitation History and Current Population Trends 11.1.3 Overview of Chapter 11.2 Annual Cycle and Life History 11.3 Reproductive Behavior 11.4 Molting Behavior 11.5 At-Sea Behavior 11.5.1 Horizontal Movement 11.5.2 Diving Behavior and Diet 11.5.3 Environmental Drivers of Reproductive Success 11.6 Ontogeny of Behavior 11.7 Future Directions 11.8 Conclusions References 12 Dive Types Matter: They Reveal the Foraging Ecology of Elephant Seals 12.1 Introduction 12.2 History of Dive Typing in Elephant Seals 12.2.1 Early Dive Records and First Descriptions of Dive Types 12.2.2 Swim Speed Adds a Dimension to Dive Typing 12.2.3 Microprocessor TDRs Expand Diving Studies 12.2.4 Dive Typing in Southern Elephant Seals 12.3 Sex Differences in Dive Types of Elephant Seals 12.3.1 Northern Elephant Seals 12.3.2 Southern Elephant Seals 12.3.3 Ontogeny of Diving Behavior 12.4 Validation of Dive Type Function 12.4.1 Drift Dives 12.4.2 Sex Differences 12.4.3 Importance of Measuring Swim Speed 12.5 Dive Types, Foraging Tactics, and Foraging Success 12.5.1 3-D Movements, Body Position, and Activity 12.5.2 Prey Density 12.5.3 Body Condition, Foraging Success, and Cost of Transport 12.5.4 Feeding and Consumption of Prey 12.5.5 Prey and Diet 12.6 Dive Types in Other Pinnipeds and Whales 12.7 Conclusions References 13 The Weddell Seal: Eco-Physiological Adaptations to a High-Latitude Seasonal Environment 13.1 Introduction 13.2 Population Size and Distribution 13.3 Demography and Vital Rates 13.4 The Annual Cycle—Temporal Alignment with Environmental Constraints 13.4.1 Female Pupping and Lactation 13.4.2 Breeding Behavior 13.4.3 Vocal Behavior 13.4.4 Pup Dive and Post-Weaning Development 13.4.5 Late Summer Activities 13.4.6 The Annual Molt 13.4.7 The Austral Winter 13.5 Physiological Underpinnings of Dive Behavior 13.6 Diet 13.7 A Population at the Edge 13.8 Concluding Remarks References 14 The Harp Seal: Adapting Behavioral Ecology to a Pack-Ice Environment 14.1 Introduction 14.2 History 14.3 Breeding 14.3.1 Lactation 14.3.2 Males 14.3.3 Pup Development 14.3.4 Pup Thermoregulation 14.3.5 Postweaning Transition 14.3.6 Behavioral Responses to Danger 14.3.7 Mating Behavior 14.4 Molt 14.5 Post-Molt 14.6 Fall 14.7 Diet 14.8 Conclusions and Future Directions References 15 The Ringed Seal: Behavioral Adaptations to Seasonal Ice and Snow Cover 15.1 Introduction 15.2 History 15.3 Behavioral Adaptation to Ice and Snow 15.4 Movements 15.4.1 Foraging Period 15.4.2 Subnivean Period 15.4.3 Basking Period 15.5 Navigation 15.5.1 Foraging Period 15.5.2 Subnivean Period 15.5.3 Basking Period 15.6 Diving and Foraging 15.6.1 Foraging Period 15.6.2 Subnivean Period 15.6.3 Basking Period 15.7 Social and Mating Behavior 15.7.1 Foraging Period 15.7.2 Subnivean Period 15.7.3 Basking Period 15.8 Predator Avoidance 15.8.1 Foraging Period 15.8.2 Subnivean Period 15.8.3 Basking Period 15.9 Future Directions References 16 The Hawaiian Monk Seal: Ethology Applied to Endangered Species Conservation and Recovery 16.1 Overview and Conservation Status 16.1.1 Conservation Status and Threats 16.1.2 Modes of Research and Ethological Observation 16.2 Reproductive Behavior—Influences on Reproduction and Survival 16.2.1 Reproductive Biology 16.2.2 Mom and Pup Interactions 16.2.3 Male and Female Interactions 16.2.4 Conservation Interventions to Mitigate Threats of Male Aggression 16.3 Social Behavior—Influences on Disease Spread and Mitigations 16.3.1 Implications for Disease Spread and Vaccination 16.3.2 Vaccination as a Conservation Intervention 16.4 Foraging Behavior—Influences on Survival and Exposure to Risk of Fisheries Interactions 16.4.1 Diet 16.4.2 Habitat Use—Horizontal 16.4.3 Habitat Use—Vertical 16.4.4 Foraging Behaviors 16.4.5 Interventions to Mitigate Food Limitation 16.4.6 Interventions to Mitigate Fisheries Interactions 16.5 Dispersal Behavior and Site Fidelity—Influences on the Success of Translocation as a Conservation Tool 16.5.1 Dispersal Patterns and Site Fidelity 16.5.2 Translocation as a Conservation Intervention 16.6 Conclusions and Future Directions 16.7 Appendix Mediterranean Monk Seal Monachus Monachus References Ethology and Behavioral Ecology of Phocids: Concluding Remarks References