Abstract: An important question in state-dependent behaviour is how multiple influences on state are integrated to determine current behaviour. Aggressive behaviour is known to be affected by a prior contest experience. Nevertheless, whether and how multiple prior fighting experiences are integrated into a fighting decision remain unexplored. In this study, individuals ofRivulus marmoratus(Cyprinodontidae), a hermaphroditic fish, were given different combinations of two prior fighting experiences to investigate: (1) the effect of penultimate experiences on the probability of winning a subsequent contest; (2) the relative effect of a recent win and loss; and (3) whether the effect of a winning experience was as short lived as observed in other species. Penultimate and recent fighting experiences were given to the test fish approximately 48 and 24 h prior to the dyadic contests, respectively. From the results of the five types of contests staged, we conclude that: (1) penultimate fighting experiences had a significant effect on the probability of winning a subsequent contest; (2) a more recent experience had a more pronounced effect than an earlier experience, which suggested that the effect of a fighting experience would decay and/or the effect of a recent experience would interfere with the effect of an earlier experience; (3) no asymmetric effect between a winning experience and a losing experience was detected; and (4) the effect of both a winning and a losing experience lasted for at least 48 h inR. marmoratuswhich was the maximum time tested in these experiments. The possible reasons for the differences in results among studies of experience effects on contest outcomes are discussed.

Abstract: The definition of tool proposed by Beck (1980) is still the one referred to in ethology when discussing the question of tool-use in animals, and its pertinence is rarely questioned. However, observations on technical behaviours in animals have multiplied over the last 20 years, and these have profoundly altered our earlier representations. In the present article, we show that Beck's definition is insufficient and that it does not, in fact, work. More generally, we replace a theory of tools with a theory of mediations of actions to account for technical behaviours in animals. We show that a culturally overcharged notion such as that of tool hinders our perception of the diversity and the complexity of tool uses. By speaking of mediations of actions and not of tools, we eliminate the problem of first defining the pertinent object (is it a tool or not?) and are free to concentrate on the means by which the animal externalizes its actions and thus procures greater means of acting on these within a group. In so doing, we prepare the ground for a genuine evolutionary understanding of the dynamics of actions within a given animal population. Whereas, with a few exceptions, ethologists have always separated the question of techniques from that of social behaviour, we emphasize the importance of an ecology of mediations of actions for understanding the structure and dynamics of animal societies, in particular by attempting to rethink such notions as “culture” in the perspective of a general analysis of mediations of actions.

Abstract: When animals learn a simultaneous discrimination, some of the value of the positive stimulus (S+) appears to transfer to the negative stimulus (S-). The present experiments demonstrate that such value transfer can also be found in humans. In Experiment 1 humans were trained on 2 simple simultaneous discriminations, the first between a highly positive stimulus, A (1,000 points); and a negative stimulus, B (0 points); and the second between a less positive stimulus, C (100 points); and a negative stimulus, D (0 points). On test trials, most participants preferred B over D. In Experiments 2 and 3 the value of the 2 original discriminations was equated in training (A[100]B[0] and C[100]D[0]). In Experiment 2 the values of the positive stimuli were then altered (A[1,000]C[0]); again, most participants preferred B over D. In Experiment 3, however, when the values of B and D were altered (B[1,000]D[0]), participants were indifferent to A and C. Thus, the mechanism that underlies value transfer in humans appears to be related to Pavlovian second-order conditioning. Similar mechanisms may be involved in assimilation processes in social contexts.

Abstract: It has been proposed that use of socially acquired information by animals should increase as the time available for individual resource sampling decreases. We gave Norway rat “observers” either 2 or 5 h day-1 to sample four foods. Three of these foods were relatively palatable, but protein-poor; the fourth was relatively unpalatable, but protein-rich. We found that observer rats that for 2 h day-1 both sampled foods and interacted with demonstrators eating only the protein-rich food ate more of the protein-rich food than did observers that sampled for 2 h day-1 but had no opportunity to interact with demonstrators. On the other hand, observer rats that could sample foods for 5 h day-1 ate equal amounts of protein-rich food whether they interacted with a demonstrator fed protein-rich food or not. Subsequent analyses showed that the time available to observers to sample foods, rather than the opportunity to interact with demonstrators determined whether such interaction influenced observers' food choices. The results are consistent with the hypothesis that animals increase their use of public information in response to temporal constraints on opportunities for resource sampling.

Abstract: Description
From reviews of previous editions: “Professional naturalists will find [these volumes] invaluable as a handy reference, and amateurs at least those citizens alive to their earthly environment should delight in finding so much fascinating information made so available and palatable. Audubon ”What an amazing lot mammals are, seen here in all of their diversity! . . . Walker has made available a mine of information, for the specialist as well as for the casually interested . . . If you want to find out about a mammal, then, here is the place to look.“New York Times ”Every mammalogist must have [these books], and those who profess a broad interest in the fauna of the world will want them.“Natural History From aardwolves and bandicoots to yapoks and zorillas, Ernest P. Walker's Mammals of the World is the most comprehensive the pre-eminent reference work on mammals. Now, completely revised and updated, this fascinating guide is better than ever. Providing a complete account of every genus of mammal in all historical time, the sixth edition is 25 percent longer than its predecessor. Of the previous generic accounts, 95 percent have been substantively modified, and there are 80 new ones among them, three remarkable, large ungulates recently discovered in the forests of Indochina. New also is a full account of the woolly mammoth, now known to have survived until less than 4,000 years ago. Each section of the book describes one genus and includes facts such as scientific and common names, the number and distribution of species, measurements and physical traits, habitat, locomotion, daily and seasonal activity, population dynamics, home range, social life, reproduction, and longevity. Textual summaries present accurate, well-documented descriptions of the physical characteristics and living habits of mammals in every part of the world. As in the last two editions, the names and distributions of every species of every genus are listed in systematic order. These lists have now been cross-checked to ensure coverage of all species in the comprehensive new Smithsonian guide, Mammal Species of the World. Facts on the biology of mammals have been brought together from more than 2,700 newly cited references, nearly all published in the last decade. Also new are the latest data on reproduction, longevity, fur harvests, numbers in the wild and in captivity, and conservation status. The sixth edition also records all official classifications of every mammal species and subspecies in the massive 1996 IUCN Red List of Threatened Animals. The illustrations more than 1,700 include virtually every genus of mammal. Among them are pictures by such noted wildlife photographers as Leonard Lee Rue III, Bernhard Grzimek, David Pye, and Warren T. Houck. Mammals pictured here for the first time include the just-discovered giant muntjac deer of Viet Nam, a rodent known only from the Solomon Islands, a large fruit bat whose male suckles the young, and an extremely rare web-footed tenrec of Madagascar. Since its publication in 1964, Walker's Mammals of the World has become a favorite guide to the natural world for general readers as well as an invaluable resource for professionals. This sixth edition represents more than half a century of scholarship? Ernest P. Walker himself devoted more than thirty years to the original project and remains true to Walker's vision, smoothly combining thorough scholarship with a popular, readable style to preserve and enhance what the Washington Post called ”a landmark of zoological literature."
Reviews
“"An absolute treasure trove--a 'must' for the working naturalist as well as for any person who has curiosity about the world's mammals.”Roger Tory Peterson."?
“Unlike many academic reference works, all editions [Walker's Mammals], the new one included, are as accessible to amateurs as to professionals . . . For wildlife enthusiasts, this two-volume set is an indispensable resource. The new edition not only updates taxonomic information generated in the last 10 years, it pushes back the historical record, including all mammals known to have existed in the past 5,000 years. Twenty-one new genera also appear, animals that have recently been discovered. Either volume is hefty enough to kill a small mammal if dropped there's a total of 2,160 pages . . . And despite almost a decade between editions the last edition appeared in 1991 the price has remained virtually the same, despite an increase in book size of more than 20 percent. After being exposed to this kind of thorough, detailed information saturation, many readers may find it hard to go back to a plain old encyclopedia for their animal questions.”Bloomsbury Review
“For anyone who needs an up-to-date, comprehensive guide to every known species of mammal, Walker's Mammals of the World is an essential purchase.”Nicholas Gould, International Zoo News
“A massive compilation ideal for readers who want to have at their fingertips information on every mammal species.”International Zoo News
Author Information
Ernest P. Walker (1891-1969) began work on Mammals of the World in the early 1930s, when he became assistant director of the National Zoo in Washington. His work reflected an unequaled store of knowledge about the world's mammals. Ronald M. Nowak was senior author of the fourth edition and author of the fifth edition of Walker's Mammals of the World. His other works on mammalogy include North American Quaternary Canis and several parts of the National Geographic Society's Wild Animals of North America, for which he also was editorial consultant. He received a Ph.D. in biology from the University of Kansas in 1973 and was staff mammalogist at the former Office of Endangered Species, U.S. Fish and Wildlife Service, from 1974 to 1987. He served as an Air Force officer for four years and is a private pilot.