Home Ranges of Animals: Cognitive Maps, Research Approaches, and Insights By Roger A. Powell, Oxford, United Kingdom: Oxford University Press. 2025. pp. 238. 155. 00 (hardback). ISBN: 9780192858337

Home Ranges of Animals, by Roger A. Powell, is an amalgamation of the author's lifetime of experience as a wildlife researcher, field biologist, statistician, naturalist, idealist, visionary, and mentor. Across 238 pages and 13 chapters, Powell guides readers on a journey that challenges, inspires, and ultimately reshapes how animal cognition and movement across landscapes are understood. Having dedicated his career to understanding how animals perceive their environments and how those perceptions influence behavior and decision-making, Powell is widely regarded as a pioneer in ecology and a mentor to generations of scientists. This book represents yet another avenue through which he shares his knowledge, enabling both emerging and established ecologists to stand on the shoulders of giants. Home Ranges of Animals weaves together themes about animal cognition, movement, home-range theory, terminology, modeling approaches ranging from simple to complex, and real-world applications, enriched by the author's extensive field experience and thought-provoking examples. Its structure makes the material accessible to readers with diverse backgrounds, from those with minimal experience in modeling to those well versed in constructing animal utilization distributions or, as Roger Powell suggests, familiarity distributions. Throughout, Powell draws upon his own research with species such as black bears (Ursus americanus) and fishers (Pekania pennanti), while also acknowledging foundational contributions from ecological pioneers, including Charles Darwin, Aldo Leopold, and William Burt. He enhances understanding using relatable analogies, such as comparing territoriality to private property ownership, and by linking his personal experiences, like navigating landscapes on a bicycle, to how animals form cognitive maps of resources. Powell even tracked his own movements over 65 randomly selected days between 1990 and 1991, quantified his home range using 5 different metrics, and compared the results to evaluate the efficacy of conventional familiarity distribution estimators. These perspectives challenge readers to reconsider long-held assumptions about animal cognition and spatial behavior while highlighting both the utility and the limitations of classic familiarity distribution estimators. In Chapter 1, An Introduction to Home Ranges, Powell establishes key concepts, including definitions of home ranges, challenges associated with their study, research design, and an overview of the book's organization. Notably, Powell introduces the term familiarity distribution as a replacement for utilization distribution, emphasizing that animals perceive and develop familiarity with their landscapes. He also defines what a mechanistic distribution is and highlights its value in hypothesis testing. In Chapter 2, Territories, Powell defines key terminology and explores variation in territorial behavior, advertisement, territory size, and population regulation. Although the chapter is relatively brief, only 6 pages, the discussion of territorial variation is central to understanding territoriality. This section may be particularly valuable for early-career ecologists seeking guidance on the different forms and functions of territories. In Chapter 3, Cognitive Maps and the Definition of a Home Range, Powell examines the development of the cognitive map concept, anatomical mechanisms underlying learning and memory, navigation, and alternative ways of conceptualizing and describing home ranges. Arguably, the highlight of the chapter is his detailed explanation of how an animal's cognitive map shapes its home range, an approach that challenges readers to reconsider conventional interpretations of spatial behavior. A recurring theme throughout the book is Powell's method of presenting a traditional definition of a key concept related to home range, evaluating its strengths and limitations in capturing the underlying biological reality, and then proposing revisions informed by his own research and experience. In this chapter, he directly confronts the shortcomings of the traditional definition of a home range and offers amendments that this reviewer finds warranted, insightful, and entirely appropriate. Chapter 4, Movement, provides a detailed overview of movement metrics, dead reckoning, and dispersal, proposes standardized terminology, and addresses issues such as data gaps and autocorrelation. Powell offers clear definitions of essential terms, including path, step, segment, bout, dispersal, migration, sinuosity, and tortuosity, terminology that this reviewer recommends for broader adoption in wildlife studies to promote clarity and consistency. In Chapter 5, Information, Movements, and Home Ranges, Powell explores memory, information acquisition and decay, foraging behavior, and revisitation of resource patches, highlighting how information shapes movement and use of the environment. These ideas connect directly to a broader body of literature addressing rates of information loss, return times to resource patches, and related questions in animal cognition. The reviewer anticipates that this chapter, in particular, will serve as a valuable resource for researchers pursuing work in these areas. In Chapter 6, Mechanistic Familiarity Distributions, Powell describes mechanistic distributions, their value for hypothesis testing, and the advantages of integrating mechanistic and familiarity-based approaches. The chapter draws extensively on his own methodological contributions and is strengthened considerably by his long-standing experience developing and applying mechanistic distributions to evaluate ecological hypotheses. In Chapter 7, Economic and Cost-Benefit Models and Home Ranges, Powell introduces modeling frameworks related to resource productivity, territorial costs and benefits, and their links to cognitive maps. Although this chapter is heavily centered on models and equations, it is enriched with examples from his research on black bears, which help make the concepts accessible to a broad audience. In Chapter 8, Foraging Optimally for a Home Range, Powell applies optimal foraging theory using linear programming, resource-maximizing, and area-minimizing models, with detailed case studies involving black bears and wolves (Canis lupus) and a discussion of optimal patch choice. This chapter clearly demonstrates how incorporating the optimal selection of resource-bearing patches can yield insights beyond those provided by static models based primarily on movement parameters alone. In Chapter 9, Game Theory and Home Ranges, Powell introduces game-theoretic concepts, including hawk–dove (reframed as boxer–dancer) and war-of-attrition games, supplemented by numerous examples and thoughtful discussion of their limitations. In Chapter 10, Familiarity Distributions I, Powell introduces the concept of familiarity distributions, provides context, and outlines tools and methods for their quantification. Powell addresses sources of error, issues related to autocorrelation, and the rationale for excluding data. The chapter concludes with 6 recommended steps for comparing familiarity distributions across studies, guidance that the reviewer strongly encourages the field to adopt. In Chapter 11, Building Familiarity Distributions, Powell focuses on the construction and interpretation of fixed and adaptive kernel estimators, bridge methods, and local convex hull approaches, along with comparisons among these techniques. The reviewer strongly recommends this chapter to spatial and movement ecologists, especially early-career researchers interested in learning about the different approaches for generating familiarity distributions. In Chapter 12, Familiarity Distributions III, Powell examines overlap, core areas, interactions, and territoriality, and discusses customization of familiarity distributions, including the incorporation of behavior, perception, and sensory information. Powell also evaluates the correspondence between familiarity distributions and cognitive maps using his own location data as a case study. The final chapter, A Doorway to New Cognitions on Home Ranges, synthesizes the book's themes and explores future directions, including hypothesis testing, machine learning applications, and the role of the hippocampal complex in spatial cognition. Powell concludes by posing a final question: Why home ranges? He emphasizes that home ranges are a fundamental concept for understanding how animals perceive their environment, whereby animals integrate that information into their movements. Overall, Home Ranges of Animals is an essential resource for wildlife professionals interested in animal cognition, decision-making, and spatial ecology. While all chapters contribute meaningfully to the book's impact, Chapters 4 and 10–12 are particularly valuable for researchers studying animal movement and distribution. The artwork by Consie Powell is exceptional, vividly illustrating key concepts. The cover art, in particular, effectively conveys the diversity of landscape elements incorporated into an animal's cognitive map and reflected in familiarity distributions. This well-written and informative volume is poised to become foundational reading for both early-career and established ecologists and should be required reading for courses in animal spatial and movement ecology. The authors declare no conflicts of interest.