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.

This comprehensive reference is clearly destined to become the definitive anatomical basis for all molecular neuroscience research. The three volumes provide a complete overview and comparison of the structural organisation of all vertebrate groups, ranging from amphioxus and lamprey through fishes, amphibians and birds to mammals. This thus allows a systematic treatment of the concepts and methodology found in modern comparative neuroscience. Neuroscientists, comparative morphologists and anatomists will all benefit from: * 1,200 detailed and standardised neuroanatomical drawings * the illustrations were painstakingly hand-drawn by a team of graphic designers, specially commissioned by the authors, over a period of 25 years * functional correlations of vertebrate brains * concepts and methodology of modern comparative neuroscience * five full-colour posters giving an overview of the central nervous system of the vertebrates, ideal for mounting and display This monumental work is, and will remain, unique; the only source of such brilliant illustrations at both the macroscopic and microscopic levels.

How can we explain the peacock's beautiful tail decorations, or the wonderful song of the nightingale? Why are some smells nice and others nasty? How do animals signal their intentions and qualities to potential partners? How do offspring tell parents about their needs? Are signals tuned to the environment, and to the mental abilities of receivers? Essential for understanding how animals cope with their ecological and social environment, the study of animal signals is one of the most active research areas in evolutionary biology. Understanding the signalling systems of nature has wide-ranging relevance including biological conservation and human communication. Written by international scientists, this is a comprehensive overview of the fascinating diversity of animal signals and signalling functions. Combining reviews and research, the book is aimed at both students and professional scientists.