The revised and updated edition of Animal tool behavior: The use and manufacture of tools by animals by R. W. Shumaker, K. R. Walkup, and B. B. Beck contains a rather comprehensive account of tool use and manufacture by an array of non-human animals.  At the start, the authors offer an engaging review of existing definitions of tool use, discussing their strengths and (mostly) their weaknesses.  Then, they cleverly address the challenging issue of defining ‘tool use’ by offering their own definition, which is the one used in the text to identify and classify a variety of seemingly heterogeneous behaviors as examples of tool use.  Their definition may appear to rely on the construct of ‘intention’ (i.e., an event internal to the animal observed and thus not directly observable) to identify the aim(s) of an animal’s actions.  In fact, it does not.  The authors offer a means by which the animal’s intention ‘to alter more efficiently the form, position, or condition of another object, another organism, or the user itself’ (p. 5) can be reliably assessed by detecting the presence of specific behaviors before and during tool use, namely, ‘when the user holds and directly manipulates the tool during or prior to use and is responsible for the proper and effective orientation of the tool.'(p. 5).  Predictably, the same concrete and precise criteria applied to the conceptualization of ‘tool use’ are relied upon for the definition of ‘tool manufacture’, which is described as ‘any structural modification of an object or an existing tool so that the object serves, or serves more effectively, as a tool.’ (p. 11).  The requirement that the actions involved in tool manufacture be structural in nature, which implies that the physical characteristics of the object used as tool are to be altered, makes the definition of tool manufacture not only precise but also stringent, excluding behaviors that involve simple changes in the spatial orientation of an object.  As is often the case in behavioral taxonomies, definitions may contain a few expressions that rely heavily on the observer’s best judgment for their application, such as ‘more efficiently’ for the classification of actions pertaining to ‘tool use’ and ‘more effectively’ for the cataloging of actions concerning ‘tool manufacture’.  Of course, vagueness can be easily overcome if operational definitions of efficiency and effectiveness are adopted and applied to specific behaviors during observation.

Given the authors’ careful wording of key concepts, not surprising is that their selection of behaviors defined as tool use and manufacture is rather comprehensive, including both wild and captive animals.  Coverage, albeit comprehensive, is cleverly selective.  For instance, narratives justly exclude forms of tool behavior that animals exhibit as the product of human training, even though such forms of behavior illustrate the boundaries of taxa’s capabilities.  Nevertheless, as the authors recognize, coverage is based on the availability of records of such behaviors, making the narratives devoted to diverse non-human animals skewed towards creatures that scientists have studied the most.  Consequently, the amount of text devoted to each taxon and species is not to be treated comparatively as an indication that variety and frequency of tool use and construction are greater or less in a species or taxon than in another. 

Lastly, the authors introduce a chapter devoted to debugging seven myths concerning tool use and manufacture, including issues such as whether tool behavior is necessarily based on complex cognition, whether tool use and construction is unique to primates, and whether the amount of time that animals (e.g., apes) spend in contact with human beings influence quality and frequency of tool-related behavior, etc.  Of course, these myths can easily be addressed by reading the preceding chapters, those devoted to tool use and construction in a variety of both vertebrates and invertebrates.  The obvious answers given to each myth combined with the relaxed treatment of key terminology and the aim to summarize a vast body of evidence in a few pages of text make the last chapter a substantial departure in style and content from the rigor of the preceding chapters.  For instance, references to ‘intelligent behavior’ are made without a clearly defined operational definition of the term (at least one upon which some consensus exists), rendering the narrative disappointing.  Important to recognize, however, is that if the chapter is a substantial departure from the detailed, concrete narrative of the earlier chapters, where behaviors are enumerated and described, the reason is that its intent is speculative in nature.  As such, the chapter is engaging and slightly provocative, metaphorically resembling the closing of a long day of field work, when researchers may relax by chatting casually about their findings and related implications. 

Animal tool behavior is a read for a wide audience of individuals interested in understanding not only the range of behaviors of which non-human animals are capable, but also cognition, conceptualized both as a set of abilities and as an array of mental operations.  Insight into cognition can be achieved by extrapolation from observed behavior in such animals because no thorough and explicit treatment of non-human animal cognition is embedded in the text.  Nevertheless, detailed descriptions of behaviors reflecting tool use and manufacture that the authors offer allow the reader to go beyond descriptive information to infer the presence of particular skills and mental processes.  Inferences regarding cognition offer the reader an opportunity to enhance his/her comprehension of the similarities and differences that may exist between species in the animal kingdom.  Overall, the authors’ writing is engaging and transparent, making the text an excellent introduction to the animal kingdom from a functional perspective whereby taxa and species that are structurally different are linked to goal-directed activities that may either reflect such differences or exemplify underlying similarities. 

© 2011 Maura Pilotti

 Maura Pilotti, Ph.D., Department of Psychology, Hunter College, New York