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Space use is a fundamental characteristic that informs our knowledge of social relationships and the degree to which individuals are territorial. Until recently, relatively little was known about the spatial ecology and social organization of swift foxes (Vulpes velox (Say, 1823)). We investigated space use of swift foxes on shortgrass prairie in northeastern Colorado. Our first objective was to evaluate sizes of seasonal and annual home ranges and core areas of 13 radio-collared swift foxes monitored continuously for 2 years. Our second objective was to compare home-range and core-area overlap of breeding pairs to that of neighboring foxes, including male-male, female-female, and nonbreeding female-male dyads. Home-range size in our study population was among the smallest previously reported for swift foxes. Males tended to have slightly larger home ranges and core areas than females, and home-range size was significantly larger in the breeding season than in both the pup-rearing and the dispersal seasons; sizes of core areas did not differ seasonally. Spatial overlap between breeding pairs was substantial, whereas spatial overlap between neighbors, particularly males, was low, suggesting territoriality. Key words: Vulpes velox, home range, core area, seasonal, overlap, territoriality. L'utilisation de l'espace est une caracteristique fondamentale qui permet de connaitre les relations sociales et l'importance de la territorialite chez les individus. Jusqu'a recemment, on savait relativement peu de choses sur l'ecologie spatiale et l'organisation sociale des renards veloces (Vulpes velox (Say, 1823)). Nous avons etudie l'utilisation de l'espace chez les renards veloces dans la prairie d'herbes courtes du nord-est du Colorado. Notre premier objectif etait d'evaluer les domaines vitaux saisonniers et annuels et les aires centrales de 13 renards veloces porteurs de colliers radio suivis continuellement pendant 2 annees. Notre second objectif etait de comparer le chevauchement des domaines vitaux et des aires centrales des couples reproducteurs a celui de renards voisins, incluant des dyades male-male, femelle-femelle et femelle-male non reproducteurs. La taille du domaine vital observe dans la population etudiee est parmi les plus petites jamais signalees chez le renard veloce. Les males ont tendance a posseder un domaine vital et une aire centrale plus etendus que ceux des femelles; la taille du domaine vital est significativement plus grande durant la saison de reproduction que durant les deux saisons d' elevage des petits et de dispersion. La taille des aires centrales ne varie pas en fonction de la saison. Le chevauchement spatial est considerable entre les couples reproducteurs, alors que le chevauchement spatial entre les voisins, particulierement les males, est faible, ce qui laisse croire a l'existence de territorialite. Mots-cles : Vulpes velox, domaine vital, aire centrale, saisons, chevauchement, territorialite. [Traduit par la Redaction], Introduction Space use is a fundamental behavioral and ecological characteristic that informs our knowledge of an animal's interactions with its environment, including relationships with others in the population and the [...]

Few researchers have used radiotelemetry to study spatial organization in beavers (Castor canadensis) given limitations in available radio-attachment methods for the species. During Mar. 2005-Sept. 2006, we attached tail-mounted transmitters to 46 beavers from 10 colonies in an unexploited beaver population in southern Illinois. We used radiotelemetry to quantify sizes and percentage overlap of composite and seasonal home ranges and core areas of beavers and tested for differences by age and sex. Composite home ranges and core areas averaged 25.5 ha and 3.9 ha in size, respectively, and did not differ between age and sex (P > 0.41). There was no difference in seasonal home range sizes between age or sex (P > 0.14); however, pooled home range sizes differed by season and year (P = 0.007). Seasonal core area size did not differ among age, sex, or season (P > 0.10). Percentage of seasonal home range overlap approached significance among seasons (P = 0.077), and seasonal core area overlap differed by season (P = 0.005). Mean composite colony home ranges and core areas were 22.7 ha and 3.5 ha in size, respectively. Nine out of 11 colonies had overlapping home ranges with [greater than or equal to] 1 neighboring colony ([bar.x] overlap = 9.8 [+ or -] 1.5%) and to our knowledge represents the only known documented colony home range overlap in this species., INTRODUCTION Understanding use of space leads to elucidation of species ecology, evolution, and the factors that influence populations (Young and Shivik, 2006). Generally, spatial organization and movement of species is [...]

Synchronous interactions arise in various animal species that rhythmically broadcast acoustic, vibratory, and visual signals. These interactions are characterized by a coincidence in both rate and phase of the rhythms of neighboring signalers. Theory predicts several ways in which synchronized rhythms may specifically benefit the interacting signalers. However, synchrony may also arise as an emergent property, a default phenomenon that is neither preferred by conspecific receivers evaluating the signals nor advantageous to the signalers themselves. Here, we examine several well-studied cases of acoustic synchrony in Neoconocephalus katydids (Orthoptera: Tettigoniidae), a New World genus wherein males broadcast loud advertisement songs. We report that call synchrony found in N. spiza and N. nebrascensis results from two rather different mechanisms of rhythm adjustment. Moreover, synchrony in the former species appears to represent an incidental byproduct of signal competition between evenly matched males, whereas in the latter species synchrony functions as a specific adaptation in which cooperating males ensure that critical call features can be perceived by females. We discuss the separate evolutionary trajectories that may have led to similar outcomes, synchronous chorusing by advertising males, in these closely related species. Keywords: acoustic communication, mate choice, sexual selection, signal interactions, species recognition

Analysis of acoustic interactions between animals in active choruses is complex because of the large numbers of individuals present, their high calling rates, and the considerable numbers of vocalizations that either overlap or show close temporal alternation. The authors describe a methodology for recording chorus activity in bullfrogs (Rana catesbeiana) using multiple, closely spaced acoustic sensors that provide simultaneous estimates of sound direction and sound characteristics. This method provides estimates of location of individual callers, even under conditions of call overlap. This is a useful technique for understanding the complexity of the acoustic scene faced by animals vocalizing in groups. Keywords: bullfrog, chorus, advertisement call, auditory scene, microphone array

A characteristic feature of hearing systems is their ability to resolve both fast and subtle amplitude modulations of acoustic signals. This applies also to grasshoppers, which for mate identification rely mainly on the characteristic temporal patterns of their communication signals. Usually the signals arriving at a receiver are contaminated by various kinds of noise. In addition to extrinsic noise, intrinsic noise caused by stochastic processes within the nervous system contributes to making signal recognition a difficult task. The authors asked to what degree intrinsic noise affects temporal resolution and, particularly, the discrimination of similar acoustic signals. This study aims at exploring the neuronal basis for sexual selection, which depends on exploiting subtle differences between basically similar signals. Applying a metric, by which the similarities of spike trains can be assessed, the authors investigated how well the communication signals of different individuals of the same species could be discriminated and correctly classified based on the responses of auditory neurons. This spike train metric yields clues to the optimal temporal resolution with which spike trains should be evaluated. Keywords: neural encoding, temporal resolution, intrinsic noise, spike distance metric, sexual selection

Cross-fostered as infants in Reno, Nevada, chimpanzees (Pan troglodytes) Washoe, Moja, Tatu, and Dar freely converse in signs of American Sign Language with each other as well as with humans in Ellensburg, Washington. In this experiment, a human interlocutor waited for a chimpanzee to initiate conversations with her and then responded with 1 of 4 types of probes: general requests for more information, on-topic questions, off-topic questions, or negative statements. The responses of the chimpanzees to the probes depended on the type of probe and the particular signs in the probes. They reiterated, adjusted, and shifted the signs in their utterances in conversationally appropriate rejoinders. Their reactions to and interactions with a conversational partner resembled patterns of conversation found in similar studies of human children.

The ability to recognize individuals can convey significant benefits to social animals. In humans, the capacity to recognize different faces is crucial for making individual behaviour predictable for other members [...]

Monkeys use a distinct set of neurons to predict whether a fellow primate is likely to cooperate for a common good. Keren Haroush and Ziv Williams at Harvard Medical School [...]

Baboons can tell whether they need to make a ruckus to get attention or if they already have a captive audience. To see whether the animals adjust their mode of [...]

Physical features in the animal world are most often some sort of signal that is intended to change the behavior of whichever animal is intended to receive that signal. The acceptance of these signals is based on the receiving animal's assumption that the signals are reliable and honest.