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Chemical communication plays an important role in mammalian life history decisions. Animals send and receive information based on body odour secretions. Odour cues provide important social information on identity, kinship, sex, group membership or genetic quality. Recent findings show, that rodents alarm their conspecifics with danger-dependent body odours after encountering a predator. In this study, we aim to identify the chemistry of alarm pheromones (AP) in the bank vole, a common boreal rodent. Furthermore, the vole foraging efficiency under perceived fear was measured in a set of field experiments in large outdoor enclosures. During the analysis of bank vole odour by gas chromatography–mass spectrometry, we identified that 1-octanol, 2-octanone, and one unknown compound as the most likely candidates to function as alarm signals. These compounds were independent of the vole's sex. In a field experiment, voles were foraging less, i.e. they were more afraid in the AP odour foraging trays during the first day, as the odour was fresh, than in the second day. This verified the short lasting effect of volatile APs. Our results clarified the chemistry of alarming body odour compounds in mammals, and enhanced our understanding of the ecological role of AP and chemical communication in mammals. [ABSTRACT FROM AUTHOR]

The rather limited human ability to understand animal vision and visual signalling has frequently clouded our expectations concerning the visual abilities of other animals. But there are multiple reasons to suspect that visual signalling is more widely employed by animals than previously thought. Because visibility of visual marks depends on the background in which they are seen, species spending most of their time living in dark conditions (e.g., in forests and/or having crepuscular and nocturnal habits) may rely on bright signals to enhance visual display. Here, as a result of experimental manipulations, we present, for the first time ever, evidence supporting the use of a new channel of intraspecific communication by a mammal species, i.e., brown bear Ursus arctos adult males relying on visual marks during mating. Bear reactions to our manipulation suggest that visual signalling could represent a widely overlooked mechanism in mammal communication, which may be more broadly employed than was previously thought. [ABSTRACT FROM AUTHOR]

Acoustic signals that reliably indicate body size, which usually determines competitive ability, are of particular interest for understanding how animals assess rivals and choose mates. Whereas body size tends to be negatively associated with formant dispersion in animal vocalizations, non-vocal signals have received little attention. Among the most emblematic sounds in the animal kingdom is the chest beat of gorillas, a non-vocal signal that is thought to be important in intra and inter-sexual competition, yet it is unclear whether it reliably indicates body size. We examined the relationship among body size (back breadth), peak frequency, and three temporal characteristics of the chest beat: duration, number of beats and beat rate from sound recordings of wild adult male mountain gorillas. Using linear mixed models, we found that larger males had significantly lower peak frequencies than smaller ones, but we found no consistent relationship between body size and the temporal characteristics measured. Taken together with earlier findings of positive correlations among male body size, dominance rank and reproductive success, we conclude that the gorilla chest beat is an honest signal of competitive ability. These results emphasize the potential of non-vocal signals to convey important information in mammal communication. [ABSTRACT FROM AUTHOR]

In animal communication, acoustic signals can be used to census individuals as well as groups of individuals of the same species. The wolf (Canis lupus) is a protected species in Europe, and the study of its vocalizations may furnish information about its spatial distribution, reproductive success, and social behaviour. This study was conducted in seven locations of the Tuscan Apennines over 2 years. Seven different free-ranging wolf-packs, from different environmental habitats, were recorded. The minimum wolf number of each pack was ascertained along with the presence of pups. Different acoustic characteristics were found among packs, confirming that the group-specific vocal signature is a useful method to recognize packs in the wild. Howls were also analysed in relation to different environmental characteristics, and different frequencies were found to correlate open/closed habitats, so environmental variables should be included in sound analysis models to recognise individual packs. [ABSTRACT FROM AUTHOR]

Passive acoustic monitoring is a common method for detection of endangered North Atlantic right whales. This study reports on the acoustic behavior of right whales on the winter calving grounds to assess their acoustic detectability in this habitat. In addition to known call types, previously undescribed low amplitude short broadband signals were detected from lactating females with calves. The production of higher amplitude tonal calls occurred at lower rates for lactating females than from other age/sex classes suggesting that passive acoustic monitoring may be less effective in detecting mother-calf pairs in this critical habitat area. [ABSTRACT FROM AUTHOR]

Abstract The acoustics of male rutting roars, aside from genetic markers, are useful tools for characterization of populations and subspecies of red deer Cervus elaphus. This study of rutting mature male Pannonian red deer from Southern Hungary presents a description of the calling posture, a graphical reconstruction of the oral vocal tract length during rutting roar production and a spectrographic analyses of 1740 bouts containing a total of 5535 rutting roars. In addition, this study provides the first direct comparison of the bouts and main (=longest) rutting roars between Pannonian and Iberian red deer stags, representative of the Western and Eastern lineages of European red deer. The bouts of the Pannonian stags comprised 1–15 roars per bout; 24.37% were single-roar bouts and 23.68% were two-roar bouts. The duration of the main roars within bouts ranged from 0.52 s to 4.60 s, 1.13 ± 0.50 s on average. Main common roars (66.3% of the 1740 main roars), were longer than harsh roars (1.27 ± 0.55 s vs 0.87 ± 0.25 s) and higher in maximum fundamental frequency (179 ± 61 Hz vs 147 ± 54 Hz). In multi-roar bouts, main harsh roars were first roars in 47.4%, intermediate roars in 19.2% and last roars in 18.8% of the bouts. Bout structure and the acoustics of main roars in the Pannonian stags differed from those in the Iberian stags and in stags from other populations of Cervus elaphus. These results support the power of rutting vocalizations for consideration as an additional tool for discriminating populations and subspecies within Cervus elaphus. [ABSTRACT FROM AUTHOR]

Vocal dialects are fundamental to our understanding of the transmission of social behaviours between individuals and populations, however few accounts trace this phenomenon among mammals over time. Northern elephant seals (Mirounga angustirostris) provide a rare opportunity to examine the trajectory of dialects in a long-lived mammalian species. Dialects were first documented in the temporal patterns of the stereotyped vocal displays produced by breeding males at four sites in the North Pacific in 1968 and 1969, as the population recovered from extreme exploitation. We evaluated the longevity of these geographical differences by comparing these early recordings to calls recently recorded at these same locations. While the presence of vocal dialects in the original recordings was re-confirmed, geographical differences in vocal behaviour were not found at these breeding rookeries nearly 50 years later. Moreover, the calls of contemporary males displayed more structural complexity after approximately four generations, with substantial between-individual variation and call features not present in the historical data. In the absence of measurable genetic variation in this species—owing to an extreme population bottleneck—a combination of migration patterns and cultural mutation are proposed as factors influencing the fall of dialects and the dramatic increase in call diversity. [ABSTRACT FROM AUTHOR]

The characterization of the rabbit mammary pheromone, which is sensed by the main olfactory system, has made this species a unique model for the study of pheromonal communication in mammals. This discovery has brought attention to the global understanding of chemosensory communication in this species. Chemocommunication is mediated by two distinct organs located in the nasal cavity, the main olfactory epithelium and the vomeronasal organ (VNO). However, there is a lack of knowledge about the vomeronasal system in rabbits. To understand the role of this system, an exhaustive anatomical and histological study of the rabbit VNO was performed. The rabbit VNO was studied macroscopically by light microscopy, and by histochemical and immunohistochemical techniques. We employed specific histological staining techniques (periodic acid‐Schiff, Alcian blue, Gallego's trichrome), confocal autofluorescence, histochemical labelling with the lectin Ulex europaeus agglutinin (UEA‐I), and immunohistochemical studies of the expression of the Gαi2 and Gαo proteins and olfactory marker protein. The opening of the vomeronasal duct into the nasal cavity and its indirect communication with the oral cavity through a functional nasopalatine duct was demonstrated by classical dissection and microdissection. In a series of transverse histological sections, special attention was paid to the general distribution of the various soft‐tissue components of this organ (duct, glands, connective tissue, blood vessels and nerves) and to the nature of the capsule of the organ. Among the main morphological features that distinguish the rabbit VNO, the presence of a double envelope, which is bony externally and cartilaginous internally, and highly developed venous sinuses stand out. This observation indicates the crucial role played in this species by the pumping mechanism that introduces chemical signals into the vomeronasal duct. The functional properties of the organ are also confirmed by the presence of a well‐developed neuroepithelium and profuse glandular tissue that is positive for neutral mucopolysaccharides. The role of glycoconjugates was assessed by the identification of the α1‐2 fucose glycan system in the neuroepithelium of the VNO employing UEA‐I lectin. The pattern of labelling, which was concentrated around the commissures of the sensory epithelium and more diffuse in the central segments, is different from that found in most mammals studied. According to the expression of G‐proteins, two pathways have been described in the VNOs of mammals: neuroreceptor cells expressing the Gαi2 protein (associated with vomeronasal receptor type 1); and cells expressing Gαo (associated with vomeronasal receptor type 2). The latter pathway is absent in most mammals studied. The expression of both G‐protein families in the rabbit VNO places Lagomorpha together with rodents and insectivores in a small group of mammals belonging to the two‐path model. These findings support the notion that the rabbit possesses a highly developed VNO, with many specific morphological features, which highlights the significance of chemocommunication in this species. [ABSTRACT FROM AUTHOR]

Common bottlenose dolphins (Tursiops truncatus) use complex acoustic behaviours for communication, group cohesion and foraging. Ambient noise from natural and anthropogenic sources has implications for the acoustic behaviour of dolphins, and research shows that average ambient noise levels alter dolphin acoustic behaviour. However, when background noise levels are highly variable, the relationships between noise and acoustic behaviour over short time periods are likely important. This study investigates whether bottlenose dolphins altered the temporal and spectral qualities of their whistles in relation to the ambient noise present at the time the whistles were produced. Dolphin groups were recorded in Tampa Bay (western Florida) between 2008 and 2015. Six whistle parameters were analysed in spectrogram software (minimum frequency, maximum frequency, bandwidth, peak frequency, duration and number of inflection points) and ambient noise levels were calculated immediately prior to each whistle. Linear regression analysis indicated that the minimum, maximum and peak frequencies of whistles had significant positive relationships with the ambient noise levels present at the time of the whistles. These models suggested that for each 1 dB increase in ambient noise, minimum frequency increased by 121 Hz, maximum frequency increased by 108 Hz and peak frequency increased by between 122 and 144 Hz. As ambient noise is typically low frequency, this suggests that bottlenose dolphins increased whistle frequency in response to real-time noise levels to avoid masking. Future research to determine the fitness consequences of noise-induced changes in the communication behaviour of dolphins would be an important contribution to conservation efforts. [ABSTRACT FROM AUTHOR]

Previous studies have suggested that belugas (Delphinapterus leucas) use pulsed calls both with and without tone-like components for contact calls. However, call classification differs among researchers, and the definition of contact calls remains ambiguous. The objective of this study is to organize and integrate this information to redefine the contact calls of belugas. Our previous studies termed their contact call as PS1, which was exchanged among the belugas and was the predominant call type in isolation. PS 1 is a broadband pulsed call that sounds like a door creaking and has a duration of 0.15 to 1.5 s. Individual distinctiveness was found within a typical pulse repetition pattern of PS1. The PS1 characteristics initially described were based on one captive population. In this study, calls from another population of seven belugas of both sexes and various ages at Shimane Aquarium, Japan, were recorded from October 2014 to March 2015. The PS1 definition was expanded to broadband pulsed calls continuing for > 0.15 s, and the PS1 calls were explored from their calls. The belugas exchanged PS1 calls, but the pulse repetition pattern had various forms instead of the typical pattern suggested in previous PS1 studies. Additionally, all the PS1 calls contained a tone-like component. By reflecting on these results and referring to other previous studies, we renamed these contact calls creaking calls. Moreover, this study shows sex differences in the creaking calls. The females and juvenile male had creaking calls with an individually distinct pulse repetition pattern, while adult males had variations in pattern during free swimming. Each adult male, however, used only an individually distinct stereotype of pulse repetition pattern in a visual reunion and first-sighting context. This suggests that adult males have individualized and non-individualized creaking calls, and they use the former to advertise identity in separation, reunion, or greeting contexts. [ABSTRACT FROM AUTHOR]

Acoustic communication plays a pivotal role in conspecific recognition in numerous animal taxa. Vocalizations must therefore have discrete acoustic signatures to facilitate intra-specific communication and to avoid misidentification. Here we investigate the potential role of echolocation in communication in horseshoe bats. Although it has been demonstrated that echolocation can be used to discriminate among con- and hetero-specifics, the specific acoustic cues used in discrimination are still relatively unknown. Furthermore, the Acoustic Communication Hypothesis proposes that in multispecies assemblages, in which echolocation frequencies are likely to overlap, bats partition acoustic space along several dimensions so that each species occupies a discrete communication domain. Thus, multiple echolocation variables may be used in discrimination. The objective of this study was to investigate the potential of various echolocation variables to function as discriminatory cues in echolocation-based species discrimination. Using habituation–dishabituation playback experiments, we firstly tested the ability of Rhinolophus clivosus to discriminate between echolocation pulses of heterospecifics with either discrete or overlapping frequencies. Secondly, to determine whether R. clivosus could use echolocation variables other than frequency, we investigated its ability to discriminate among echolocation pulses differing in only one manipulated parameter. These test variables were identified by their contribution to the dissimilarity among pulses. Our results suggest that R. clivosus could discriminate readily between species using echolocation pulses with discrete frequencies. When frequencies overlapped, the ability of bats to discriminate was dependant on additional acoustic variables that defined the acoustic space occupied by the test signal. These additional acoustic variables included, but may not be restricted to, sweep rate of the FM and duty cycle. Thus, when echolocation pulses share a similar acoustic domain, bats use several cues to reliably discriminate among heterospecifics. [ABSTRACT FROM AUTHOR]

Sensory perception is of crucial importance for animals to interact with their biotic and abiotic environment. In amniotes, the clade including modern mammals (Synapsida), modern reptiles (Reptilia), and their fossil relatives, the evolution of sensory perception took place in a stepwise manner after amniotes appeared in the Carboniferous. Fossil evidence suggests that Paleozoic taxa had only a limited amount of sensory capacities relative to later forms, with the majority of more sophisticated types of sensing evolving during the Triassic and Jurassic. Alongside the evolution of improved sensory capacities, various types of social communication evolved across different groups. At present there is no definitive evidence for a relationship between sensory evolution and species diversification. It cannot be excluded, however, that selection for improved sensing was partially triggered by biotic interactions, e.g., in the context of niche competition, whereas ecospace expansion, especially during the Mesozoic, might also have played an important role. [ABSTRACT FROM AUTHOR]

Long-distance vocal communication by birds and mammals, including humans, is facilitated largely by radiation efficiency from the mouth or beak. Here, this efficiency is defined and quantified. It depends on frequency content of vocalization, mouth opening, head and upper body geometry, and directionality. Each of these factors is described mathematically with a piston-in-a-sphere model. While this model is considered a classic, never before has the high frequency solution been applied in detail to vocalization. Results indicate that frequency content in the 1–50 kHz range can be radiated with nearly 100% efficiency if a reactance peak in the radiation impedance is utilized with adjustments of head size, mouth opening, and beam direction. Without these adjustments, radiation efficiency is generally below 1%, especially in human speech where a high fundamental frequency is a disadvantage for intelligibility. Thus, two distinct modes of vocal communication are identified, (1) short range with optimized information transfer and (2) long range with maximum efficiency for release of acoustic power. [ABSTRACT FROM AUTHOR]

One of the main central processes affecting the cortical representation of conspecific vocalizations is the collateral output from the extended motor system for call generation. Before starting to study this interaction we sought to compare the characteristics of calls produced by stimulating four different parts of the brain in guinea pigs (Cavia porcellus). By using anaesthetised animals we were able to reposition electrodes without distressing the animals. Trains of 100 electrical pulses were used to stimulate the midbrain periaqueductal grey (PAG), hypothalamus, amygdala, and anterior cingulate cortex (ACC). Each structure produced a similar range of calls, but in significantly different proportions. Two of the spontaneous calls (chirrup and purr) were never produced by electrical stimulation and although we identified versions of chutter, durr and tooth chatter, they differed significantly from our natural call templates. However, we were routinely able to elicit seven other identifiable calls. All seven calls were produced both during the 1.6 s period of stimulation and subsequently in a period which could last for more than a minute. A single stimulation site could produce four or five different calls, but the amygdala was much less likely to produce a scream, whistle or rising whistle than any of the other structures. These three high-frequency calls were more likely to be produced by females than males. There were also differences in the timing of the call production with the amygdala primarily producing calls during the electrical stimulation and the hypothalamus mainly producing calls after the electrical stimulation. For all four structures a significantly higher stimulation current was required in males than females. We conclude that all four structures can be stimulated to produce fictive vocalizations that should be useful in studying the relationship between the vocal motor system and cortical sensory representation. [ABSTRACT FROM AUTHOR]

Despite growing evidence that males often associate in all-male groups, there has been no review of male savannah elephant Loxodonta africana social relationships or of the use of vocal communication within these male groups. We assess the evidence for all-male group formation and for the use of vocal communication by males throughout the savannah elephant range of southern and eastern Africa, as well as in ex-situ studies of captive animals., We derived data from two quantitative reviews of the published literature, for associations and for vocalisations, respectively. We supplemented these structured reviews with searches for books and of bibliographies., We compiled evidence from 30 studies on associative groups, and found that group size was the most commonly reported variable (mean group size reported 2-4.9; range reported 2-40 when excluding studies that included lone males)., We found 22 studies reporting evidence of vocal communication in males. A total of four studies were retrieved from both searches, indicating that these areas of research may overlap., We found that male elephants are frequently reported to be in groups, throughout their range and over time, although the groups are small: median group size was three. The diversity of male savannah elephant group sizes may indicate the behavioural flexibility of the species. It could also represent a lack of studies focusing on males. We found a paucity of research on male vocal communication (5% of studies were concentrated solely on male bioacoustics), particularly in natural settings, and few studies reported the social context or role of male vocal signals outside of musth., We see great scope for future research at the important intersection between male elephant associations and vocal communication, including research on the role of vocalisations in mediating all-male associations. [ABSTRACT FROM AUTHOR]

The barrier effect is a pervasive impact of road networks. For many small mammals individual avoidance responses can be the mechanism behind the barrier effect. However, little attention has been paid to which species and road characteristics modulate road avoidance and mortality risk. We measured the strength of the barrier effect imposed by the road on three rodent species with different body sizes and habitat specializations: Southern water vole ( Arvicola sapidus ), Mediterranean pine vole ( Microtus duodecimcostatus ) and Algerian mouse ( Mus spretus ). We analysed the effect of traffic intensity on use of space and direction of movement and the effect of road type (4-lane highway, 2-lane paved road and 1-lane unpaved road) on crossing rates with simulations of roads bisecting each home range. Finally, we estimated annual mortality risk from collision based on individual speed, crossing rates, body length, traffic volume and road width. Individual mobility and ecological preferences were assumed as two hypotheses to explain species’ responses towards roads. The effects were species-specific, with traffic intensity having a negative influence on the use of space and movement directionality only for water voles and with avoidance of paved roads being evident for the Algerian mouse. Road-kill mortality risk was high in pine voles. Habitat specialization, individual mobility and home-range location were identified as important factors of species’ responses towards roads. This study draws attention to the role of behaviour and ecological requirements as well as road characteristics on the strength of the barrier effect imposed by roads for different species. [ABSTRACT FROM AUTHOR]

Short-finned pilot whales ( Globicephala macrorhynchus) have complex vocal repertoires that include calls with two time-frequency contours known as two-component calls. We attached digital acoustic recording tags ( DTAGs) to 23 short-finned pilot whales off Cape Hatteras, North Carolina, and assessed the similarity of two-component calls within and among tags. Two-component calls made up <3% of the total number of calls on 19 of the 23 tag records. For the remaining four tags, two-component calls comprised 9%, 23%, 24%, and 57% of the total calls recorded. Measurements of six acoustic parameters for both the low and high frequency components of all two-component calls from the five tags were compared using a generalized linear model. There were significant differences in the acoustic parameters of two-component calls between tags, verifying that acoustic parameters were more similar for two-component calls recorded on the same tag than for calls between tags. Spectrograms of all two-component calls from the five tags were visually graded and independently categorized by five observers. A test of inter-rater reliability showed substantial agreement, suggesting that each tag contained a predominant two-component call type that was not shared across tags. [ABSTRACT FROM AUTHOR]

Interleukin 17 (IL-17) family members are key players in regulating the immune response in mammals. Here, we identified the IL-17C and IL-17D homologs from large yellow croaker ( Larimichthys crocea ), named Lc IL-17C and Lc IL-17D, respectively. The deduced Lc IL-17C and Lc IL-17D proteins possessed the typical IL-17 domain and shared a conserved arrangement of eight cysteine residues. Both Lc IL-17C and Lc IL-17Dc genes were constitutively expressed in all tissues examined, although at different levels. After challenge with Aeromonas hydrophila, the expression of Lc IL-17C and Lc IL-17D was significantly increased in gills, head kidney, and spleen. In the peripheral blood leukocytes (PBLs), the recombinant Lc IL-17C (r Lc IL-17C) could strongly promote the expression of chemokines (CXCL8, CXCL12, and CXCL13), proinflammatory factors (TNF-α, IL-1β, IL-6, and IFNg), and antibacterial peptide hepcidin, whereas r Lc IL-17D induced a weaker expression of these chemokines. Consistently, the culture supernatants from the PBLs treated by r Lc IL-17C showed a stronger ability to induce the migration of PBLs than those treated by r Lc IL-17D. Furthermore, both r Lc IL-17C and r Lc IL-17D could activate the NF-κB signalling in the epithelioma papulosum cyprini (EPC) cells. Taken together, these results indicated that Lc IL-17C and Lc IL-17D, although differing in their ability to mediate chemotaxis for PBLs, may promote the inflammatory response and host defence via activating NF-κB signalling. To our knowledge, this is the first report on functional identification of a IL-17C in teleost. [ABSTRACT FROM AUTHOR]

Based on prior knowledge of the in-air hearing thresholds of seals at the time, Terhune (Polar Biol 27:810-812, 2004) suggested that Weddell seals ( Leptonychotes weddellii) likely could not hear underwater calls, while they were on the ice. However, recent data on phocid hearing thresholds in the air reveal that seals have much lower detection thresholds than previously thought. A re-analysis of the situation using the lower hearing threshold data finds that many of the Weddell seal underwater calls, especially those with high-frequency components, will be audible to seals resting on the ice. Territorial males vocally defending territories under the ice during the breeding season may also be communicating with females on the ice directly above them. This communication may facilitate later mating success of those males. [ABSTRACT FROM AUTHOR]

In many species, spermatogenesis involves more cell divisions than oogenesis, and the male germline, therefore, accumulates more DNA replication errors, a phenomenon known as male mutation bias. The extent of male mutation bias (α) is estimated by comparing substitution rates of the X, Y, and autosomal chromosomes, as these chromosomes spend different proportions of their time in the germlines of the two sexes. Malemutation bias has been characterized in placental and marsupial mammals as well as birds, but analyses in monotremes failed to detect any such bias. Monotremes are an ancient lineage of egg-laying mammals with distinct biological properties, which include unique germline features. Here, we sought to assess the presence and potential characteristics of male mutation bias in platypus and the short-beaked echidna based on substitution rate analyses of X, Y, and autosomes. We established the presence of moderate male mutation bias in monotremes, corresponding to an α value of 2.12-3.69. Given that it has been unclear what proportion of the variation in substitution rates on the different chromosomal classes is really due to differential number of replications, we analyzed the influence of other confounding forces (selection, replication-timing, etc.) and found that male mutation bias is the main force explaining the between-chromosome classes differences in substitution rates. Finally, we estimated the proportion of variation at the gene level in substitution rates that is owing to replication effects and found that this phenomenon can explain>68%of these variations in monotremes, and in control species, rodents, and primates. [ABSTRACT FROM AUTHOR]

Characteristics of whistles may be used to study differentiation in dolphins to complement morphological and genetic studies. The whistles of four populations of Chinese humpback dolphins ( Sousa chinensis chinensis (Osbeck, 1765)), one population of Taiwanese humpback dolphins ( Sousa chinensis taiwanensis Wang, Yang, and Hung, 2015), and one population of Australian humpback dolphins ( Sousa sahulensis Jefferson and Rosenbaum, 2014) were compared to determine if differences in whistles support current views of population structure and regional and species differentiation in the genus Sousa Gray, 1866. Acoustic features were extracted from whistles captured by broadband recording systems. Permutational MANOVAs were conducted to test for differences between populations, regions, and species. Random forest trees were also used to classify similar whistles. A significant amount of variation in acoustic features was explained by population (pseudo F[5,2742] = 191.66, p < 0.001), regional (pseudo F[3,2741] = 280.62, p < 0.001), and species (pseudo F[1,999] = 3.7, p < 0.05) differences in humpback dolphin whistles. Random forest trees correctly classified whistles into populations from 40% to 67%, regions from 51% to 80%, and species from 74% to 80%. Differences in whistles were consistent with the current ideas of population-, regional-, and species-level differences within the genus Sousa, based on morphological and genetic data, as well as geographic distance and barriers to movement. [ABSTRACT FROM AUTHOR]

The knowledge of the vocal repertoire of pilot whales is very limited. In this paper, the vocal repertoire of long-finned pilot whales recorded during different encounters in the Vestfjord in northern Norway between November 2006 and August 2010 are described. Sounds were analysed using two different methods: (1) an observer-based audio-visual inspection of FFT-derived spectrograms, with which, besides a general variety of clicks, buzzes, nonharmonic sounds, and whistles, 129 different distinct call types and 25 subtypes were distinguished. These call types included pulsed calls and discrete structured whistles varying from simple to highly complex structures composed of several segments and elements. In addition, ultrasonic whistles previously not described for pilot whales were found. In addition to the diversity of single calls, call sequences consisting of repetitions and combinations of specific call types were recorded and (2) a parametric approach that permitted the confirmation of the high variability in pilot whale call structures was developed. It is concluded that the pilot whale vocal repertoire is among the most complex for the mammalian species and the high structural variability, along with call repetitions and combinations, require a closer investigation to judge their importance for vocal communication. [ABSTRACT FROM AUTHOR]

In animals, signaling behavior is often context-dependent, with variation in the probability of emitting certain signals dependent on fitness advantages. Senders may adjust signaling rate depending on receiver identity, presence of audiences, or noise masking the signal, all of which can affect the benefits and costs of signal production. In the cooperative breeding meerkat Suricata suricatta, group members emit soft contact calls, termed as "close calls", while foraging in order to maintain group cohesion. Here, we investigated how the close calling rate during foraging was affected by the presence of pups, that produce continuous, noisy begging calls as they follow older group members. Adults decreased their overall close call rate substantially when pups were foraging with the group in comparison to periods when no pups were present. We suggest this decrease was likely due to a masking effect of the loud begging calls, which makes the close call function of maintaining group cohesion partly redundant as the centrally located begging calls can be used instead to maintain cohesion. There was some support that adults use close calls strategically to attract specific pups based on fitness advantages, that is, as the philopatric sex, females should call more than males and more to female pups than male pups. Dominant females called more than dominant males when a pup was in close proximity, while subordinates showed no sex-based differences. The sex of the nearest pup did not affect the calling rate of adults. The study shows that meerkats modify their close call production depending on benefits gained from calling and provides an example of the flexible use of one calling system in the presence of another, here contact calls versus begging calls, within the same species. [ABSTRACT FROM AUTHOR]

Vocal divergence within species often corresponds to morphological, environmental, and genetic differences between populations. Wolf howls are long-range signals that encode individual, group, and subspecies differences, yet the factors that may drive this variation are poorly understood. Furthermore, the taxonomic division within the Canis genus remains contended and additional data are required to clarify the position of the Himalayan, North African, and Indian wolves within Canis lupus. We recorded 451 howls from the 3 most basal wolf lineages--Himalayan C. lupus chanco--Himalayan haplotype, North African C. lupus lupaster, and Indian C. lupus pallipes wolves--and present a howl acoustic description within each clade. With an additional 619 howls from 7 Holarctic subspecies, we used a random forest classifier and principal component analysis on 9 acoustic parameters to assess whether Himalayan, North African, and Indian wolf howls exhibit acoustic differences compared to each other and Holarctic wolf howls. Generally, both the North African and Indian wolf howls exhibited high mean fundamental frequency (F0) and short duration compared to the Holarctic clade. In contrast, the Himalayan wolf howls typically had lower mean F0, unmodulated frequencies, and short howls compared to Holarctic wolf howls. The Himalayan and North African wolves had the most acoustically distinct howls and differed significantly from each other and to the Holarctic wolves. Along with the influence of body size and environmental differences, these results suggest that genetic divergence and/or geographic distance may play an important role in understanding howl variation across subspecies. [ABSTRACT FROM AUTHOR]

Long-distance vocal communication exists in many group-living carnivores. Understanding its behavioral and ecological significance suffers from few quantitative studies in undisturbed, wild populations. In Yellowstone National Park, Wyoming, United States, we examined seasonal changes in occurrence of wolf howls and howling replies based on more than 11,000 unsolicited howls given over a 10-year period. Howling was 5-fold most frequent in the pre-breeding and breeding seasons. Pack howls primarily, but also single howls, were most common during these seasons. Answers during these seasons were predominately interpack howls. These howling peaks correlated with elevations in estradiol, testosterone, and luteinizing hormone reported elsewhere. Following the breeding season, overall howling abruptly decreased through March and April, although howling at den sites was frequent, particularly in April and May. Howling frequency remained low all summer, during which time answers switched abruptly and almost exclusively from interpack to intrapack. Single howls stimulated distant pack members to answer with increasing frequency as the summer progressed. Although not independent, the frequency of both total howls and interpack howling rose throughout the fall. We relate these seasonal changes in total howling and interpack answers largely to breeding and spacing behavior in pre-breeding and breeding seasons, and intrapack answers to pack cohesion in other seasons. Because our results may reflect a high-density, unexploited wolf population, comparative studies under other conditions would be useful. [ABSTRACT FROM AUTHOR]

For many years, it was believed that bird and mammal communication ‘in the dark of the night’ relied exclusively on vocal and chemical signalling. However, in recent decades, several case studies have conveyed the idea that the nocturnal world is rich in visual information. Clearly, a visual signal needs a source of light to work, but diurnal light (twilight included, i.e. any light directly dependent on the sun) is not the only source of luminosity on this planet. Actually, moonlight represents a powerful source of illumination that cannot be neglected from the perspective of visual communication. White patches of feathers and fur on a dark background have the potential to be used to communicate with conspecifics and heterospecifics in dim light across different contexts and for a variety of reasons. Here: (i) we review current knowledge on visual signalling in crepuscular and nocturnal birds and mammals; and (ii) we also present some possible cases of birds and mammals that, due to the characteristics of their feather and fur coloration pattern, might use visual signals in dim light. Visual signalling in nocturnal animals is still an emerging field and, to date, it has received less attention than many other means of communication, including visual communication under daylight. For this reason, many questions remain unanswered and, sometimes, even unasked. [ABSTRACT FROM AUTHOR]

The article presents the study on diel trends investigation in southern right whale (Eubalaena australis) mother-calf calling behavior at nursery ground of Santa Catarina. Topics discussed include use of autonomous recording unit, hydrophones with sensitivity for studying the behaviour; statistical tests done using Statistical Package for the Social Sciences software; and difference in temporal patterns in calling behavior.

The article presents the study on record sounds in the wild by the use of passive acoustic monitoring technology and characterizes franciscana dolphin clicks trains. Topics discussed include franciscana emits a wide range of click frequencies for echolocation and burst clicks for communication; click train characteristics being associated with foraging and feeding in bottlenose dolphin; and use of echolocation for prey tracking during pursuit and capture phases.

A subset of women who are exposed to infection during pregnancy have an increased risk of giving birth to a child who will later be diagnosed with a neurodevelopmental or neuropsychiatric disorder. Although epidemiology studies have primarily focused on the association between maternal infection and an increased risk of offspring schizophrenia, mounting evidence indicates that maternal infection may also increase the risk of autism spectrum disorder. A number of factors, including genetic susceptibility, the intensity and timing of the infection, and exposure to additional aversive postnatal events, may influence the extent to which maternal infection alters fetal brain development and which disease phenotype (autism spectrum disorder, schizophrenia, other neurodevelopmental disorders) is expressed. Preclinical animal models provide a test bed to systematically evaluate the effects of maternal infection on fetal brain development, determine the relevance to human central nervous system disorders, and to evaluate novel preventive and therapeutic strategies. Maternal immune activation models in mice, rats, and nonhuman primates suggest that the maternal immune response is the critical link between exposure to infection during pregnancy and subsequent changes in brain and behavioral development of offspring. However, differences in the type, severity, and timing of prenatal immune challenge paired with inconsistencies in behavioral phenotyping approaches have hindered the translation of preclinical results to human studies. Here we highlight the promises and limitations of the maternal immune activation model as a preclinical tool to study prenatal risk factors for autism spectrum disorder, and suggest specific changes to improve reproducibility and maximize translational potential. [ABSTRACT FROM AUTHOR]

Traditionally, the ultrasonic vocal repertoire of rats is differentiated into 22 kHz and 50 kHz calls, two categories that contain multiple different call types. Although both categories have different functions, they are sometimes produced in the same behavioral context. Here, we investigated the peripheral mechanisms that generate sequences of calls from both categories. Male rats, either sexually experienced or naïve, were exposed to an estrous female. The majority of sexually naïve male rats produced 22 kHz and 50 kHz calls on their first encounter with a female. We recorded subglottal pressure and electromyographic activity of laryngeal muscles and found that male rats sometimes concatenate long 22 kHz calls and 50 kHz trill calls into an utterance produced during a single breath. The qualitatively different laryngeal motor patterns for both call types were produced serially during the same breathing cycle. The finding demonstrates flexibility in the laryngeal-respiratory coordination during ultrasonic vocal production, which has not been previously documented physiologically in non-human mammals. Since only naïve males produced the 22 kHz-trills, it is possible that the production is experience dependent. [ABSTRACT FROM AUTHOR]

Historical changes in the distribution of animals on the European territory of Russia attract constant interest of specialists. In this aspect, information contained in the Economic Notes to the General Land Survey of the Russian Empire (18th-19th centuries) is of particular importance. This article presents the first results of a data analysis of mammalian fauna in boreal forests of European Russia. The data are contained in a systematic sample arranged on the basis of the Economic Notes and cover 7 governorates, 32 uyezds, and 377 specific dachas. Mentions of 1774 mammals were found: 21 names of mammals (species), 10 families, and 5 orders. For some species that are most typical and significant for boreal forests, we conducted a comparison with the present situation based on known data about historical changes in environmental conditions in the study area. [ABSTRACT FROM AUTHOR]

Olfactory communication among mammals remains poorly studied yet may be key to understanding their ecology. This is particularly true for mammalian carnivores, which rely extensively on scent marking for communication. Previous research suggests that carnivore latrines play a large role in both intra- and inter-specific communication. Despite the apparent complexity of mammal use of latrines, little work has examined behavior patterns of species that visit latrines. We used motion-triggered video cameras to study use and behavior of mammals at ocelot (Leopardus pardalis) latrines in Costa Rica. We documented temporal patterns of use by the focal species (ocelots), diversity of mammalian species using latrines, and behaviors that occurred at these sites. Ocelots showed peaks in visitation every 60-67 days and a shorter gap between intersexual versus intrasexual visits, supporting the idea that ocelot latrines are used to communicate information about reproductive status. Fourteen terrestrial mammal species visited the latrines, and these species engaged in a variety of behaviors, including mark investigation, scent marking, and acceptance of scent marks. The complexity and frequency of behaviors by nonfocal species suggest that latrines may play as important a role in communication for these other species as they do for ocelots. [ABSTRACT FROM AUTHOR]

In aversive or dangerous situations, adult rats emit long characteristic ultrasonic calls, often termed “22-kHz calls,” which have been suggested to play a role of alarm calls. Although the playback experiment is one of the most effective ways to investigate the alarming properties of 22-kHz calls, clear behavioral evidence showing the anxiogenic effects of these playback stimuli has not been directly obtained to date. In this study, we investigated whether playback of 22-kHz calls or synthesized sine tones could change the acoustic startle reflex (ASR), enhancement of which is widely considered to be a reliable index of anxiety-related negative affective states in rats. Playback of 22-kHz calls significantly enhanced the ASR in rats. Enhancement effects caused by playback of 22-kHz calls from young rats were relatively weak compared to those after calls from adult rats. Playback of synthesized 25-kHz sine tones enhanced ASR in subjects, but not synthesized 60-kHz tones. Further, shortening the individual call duration of synthesized 25-kHz sine tones also enhanced the ASR. Accordingly, it is suggested that 22-kHz calls induce anxiety by socially communicated alarming signals in rats. The results also demonstrated that call frequency, i.e., of 22 kHz, appears important for ultrasonic alarm-signal communication in rats. [ABSTRACT FROM AUTHOR]

Divergence in acoustic signals used by different populations of marine mammals can be caused by a variety of environmental, hereditary, or social factors, and can indicate isolation between those populations. Two types of genetically and morphologically distinct short-finned pilot whales, called the Naisa- and Shiho-types when first described off Japan, have been identified in the Pacific Ocean. Acoustic differentiation between these types would support their designation as sub-species or species, and improve the understanding of their distribution in areas where genetic samples are difficult to obtain. Calls from two regions representing the two types were analyzed using 24 recordings from Hawai‘i (Naisa-type) and 12 recordings from the eastern Pacific Ocean (Shiho-type). Calls from the two types were significantly differentiated in median start frequency, frequency range, and duration, and were significantly differentiated in the cumulative distribution of start frequency, frequency range, and duration. Gaussian mixture models were used to classify calls from the two different regions with 74% accuracy, which was significantly greater than chance. The results of these analyses indicate that the two types are acoustically distinct, which supports the hypothesis that the two types may be separate sub-species. [ABSTRACT FROM AUTHOR]

All odontocetes produce echolocation clicks as part of their vocal repertoire. In this paper the authors analysed inter-click-intervals in recordings from suction cup tags with a focus on the first inter-click interval of each click train. The authors refer to shorter first inter-click intervals as short first intervals (SFIs). The authors found that the context of SFI occurrence varies across three deep-diving species. In Blainville's beaked whales, 87% of click trains that were preceded by a terminal buzz started with SFIs. In Cuvier's beaked whales, only sub-adult animals produced notable amounts of SFIs. In contrast, sperm whales were much more likely to produce SFIs on the first click train of a dive. While the physiological and/or behavioural reasons for SFI click production are unknown, species differences in their production could provide a window into the evolution of odontocete echolocation. [ABSTRACT FROM AUTHOR]

Computed tomography (CT) imaging and ultrasound experimental measurements were combined to reconstruct the acoustic properties (density, velocity, and impedance) of the head from a deceased Indo-Pacific humpback dolphin (Sousa chinensis). The authors extracted 42 soft forehead tissue samples to estimate the sound velocity and density properties at room temperature, 25.0  °C. Hounsfield Units (HUs) of the samples were read from CT scans. Linear relationships between the tissues' HUs and velocity, and HUs and density were revealed through regression analyses. The distributions of the head acoustic properties at axial, coronal, and sagittal cross sections were reconstructed, suggesting that the forehead soft tissues were characterized by low-velocity in the melon, high-velocity in the muscle and connective tissues. Further, the sound velocities of melon, muscle, and connective tissue pieces were measured under different temperatures to investigate tissues' velocity response to temperature. The results demonstrated nonlinear relationships between tissues' sound velocity and temperature. This study represents a first attempt to provide general information on acoustic properties of this species. The results could provide meaningful information for understanding the species' bioacoustic characteristics and for further investigation on sound beam formation of the dolphin. [ABSTRACT FROM AUTHOR]

We studied the interactions between wild black and gold howler monkeys ( Alouatta caraya) and other mammals at three sites with different human disturbance levels and forest structures in northeastern Argentina. The main goal was to evaluate the effects of the study site and type of interaction (agonistic or non-agonistic) on the rate of interaction. In addition, we also described the associations between interspecific interaction rate, species involved, howler monkeys' activity, and seasonality. We present 50 group-years for 14 groups, collected between 2003 and 2012. We registered a total of 29 interactions (0.22 ± 0.26 interactions/100 h). Most interactions (56.7%) were agonistic (12% of high intensity and 88% of low intensity), 41.9% were neutral, and 1.5% were affiliative. We found that both factors, site and type of interaction, have an effect on the rate of interaction. Interspecific interactions were more frequent at the two sites without human settlement than in the rural site. Interspecific interactions occurred during resting (46.73%), traveling (27.40%), and feeding (25.87%). Interactions occurred throughout the year but were concentrated in August (late winter) and September (beginning of spring). Our results suggest that both site and type of interaction affected the rate of interaction between howler monkeys and other mammals in northeastern Argentina. Agonistic interactions were more frequent that non-agonistic ones, and monkeys reacted agonistically to several mammalian species, but these interactions were mainly of low intensity. [ABSTRACT FROM AUTHOR]

Animals communicate using a vast array of different signals in different modalities. For chimpanzees, vocalizations, gestures and facial expressions are all important forms of communication, yet these signals have rarely been studied together holistically. The current study aimed to provide the first comprehensive repertoire of flexibly combined (‘free’) multimodal (MM) signals, and assess individual and contextual factors influencing production of, and responses to, unimodal (UM) and MM signals in wild chimpanzees. In total, 48 different free MM signals were produced. MM signals were produced at a significantly lower rate than UM signals, but 22 of 26 focal animals were observed to produce free MM signals. The relative production rates of different types of UM and MM signals differed significantly between the behavioural contexts investigated, showing flexible use of signals across contexts. In contrast, individual factors such as age, sex or rank of signaller did not appear to influence the type of signal produced or the likelihood of eliciting a response. Finally, we compared recipient responses to free MM grunt-gesture signals and matched UM component signals and found that these MM signals were more likely to elicit a response than a grunt alone, but were as likely to elicit a response as the gesture alone. The overall findings point to a widespread capacity for wild chimpanzees to flexibly combine signals from different modalities and highlight the importance of adopting a multimodal approach to studying communication. [ABSTRACT FROM AUTHOR]

Olfaction plays a crucial role in mouse communication, providing information about genetic identity, physiological status of conspecifics and alerting mice to potential predators. Scents of animal origin can trigger physiological and behavioural responses that could affect experimental responses and impact positively or negatively on mouse welfare. Additionally, differing olfactory profiles could help explain variation in results between laboratories. A survey was sent to animal research units in the UK to investigate potential transfer of scents of animal origin during routine husbandry procedures, and responses were obtained from animal care workers and researchers using mice in 51 institutions. The results reveal great diversity between animal units regarding the relevant husbandry routines covered. Most [71%] reported housing non-breeding male and female mice in the same room, with 76% reporting that hands were not washed and gloves not changed between handling male and female mice. The most commonly reported species housed in the same facility as mice was the rat (91%), and 41% of respondents were aware that scents from rats could affect mice. Changing of gloves between handling mice and other species was reported by 79% of respondents. Depending on the aspect considered, between 18 and 33% of respondents believed human and non-human animal odours would strongly affect mouse physiology, behaviour or standardization, while approximately 32–54% believed these effects would be weak. This indicates uncertainty regarding the significance of these factors. Understanding and controlling these practices could reduce unwanted variability in experimental results and maximize welfare. [ABSTRACT FROM AUTHOR]

Background: Bitter taste perception is essential for species with selective food intake, enabling them to avoid unpalatable or toxic items. Previous studies noted a marked variation in the number of TAS2R genes among various vertebrate species, but the underlying causes are not well understood. Laurasiatherian mammals have highly diversified dietary niche, showing repeated evolution of specialized feeding preferences in multiple lineages and offering a unique chance to investigate how various feeding niches are associated with copy number variation for bitter taste receptor genes. Results: Here we investigated the evolutionary trajectories of TAS2Rs and their implications on bitter taste perception in whole-genome assemblies of 41 Laurasiatherian species. The number of intact TAS2Rs copies varied considerably, ranging from 0 to 52. As an extreme example of a narrow dietary niche, the Chinese pangolin possessed the lowest number of intact TAS2Rs (n = 2) among studied terrestrial vertebrates. Marine mammals (cetacea and pinnipedia), which swallow prey whole, presented a reduced copy number of TAS2Rs (n = 0-5). In contrast, independent insectivorous lineages, such as the shrew and insectivorous bats possessed a higher TAS2R diversity (n =52 and n = 20-32, respectively), exceeding that in herbivores (n = 9-22) and omnivores (n = 18-22). Conclusions: Besides herbivores, insectivores in Laurasiatheria tend to have more functional TAS2Rs in comparison to carnivores and omnivores. Furthermore, animals swallowing food whole (cetacean, pinnipedia and pangolin) have lost most functional TAS2Rs. These findings provide the most comprehensive view of the bitter taste gene repertoire in Laurasiatherian mammals to date, casting new light on the relationship between losses and gains of TAS2Rs and dietary specialization in mammals. [ABSTRACT FROM AUTHOR]

Background: Information transfer in mammalian communication networks is often based on the deposition of excreta in latrines. Depending on the intended receiver(s), latrines are either formed at territorial boundaries (betweengroup communication) or in core areas of home ranges (within-group communication). The relative importance of both types of marking behavior should depend, amongst other factors, on population densities and social group sizes, which tend to differ between urban and rural wildlife populations. Our study is the first to assess (direct and indirect) anthropogenic influences on mammalian latrine-based communication networks along a rural-to-urban gradient in European rabbits (Oryctolagus cuniculus) living in urban, suburban and rural areas in and around Frankfurt am Main (Germany). Results: The proportion of latrines located in close proximity to the burrow was higher at rural study sites compared to urban and suburban ones. At rural sites, we found the largest latrines and highest latrine densities close to the burrow, suggesting that core marking prevailed. By contrast, latrine dimensions and densities increased with increasing distance from the burrow in urban and suburban populations, suggesting a higher importance of peripheral marking. Conclusions: Increased population densities, but smaller social group sizes in urban rabbit populations may lead to an increased importance of between-group communication and thus, favor peripheral over core marking. Our study provides novel insights into the manifold ways by which man-made habitat alterations along a rural-to-urban gradient directly and indirectly affect wildlife populations, including latrine-based communication networks. [ABSTRACT FROM AUTHOR]

The evolutionary origins of human language are obscured by the scarcity of essential linguistic characteristics in non-human primate communication systems. Volitional control of vocal utterances is one such indispensable feature of language. We investigated the ability of two monkeys to volitionally utter species-specific calls over many years. Both monkeys reliably vocalized on command during juvenile periods, but discontinued this controlled vocal behavior in adulthood. This emerging disability was confined to volitional vocal production, as the monkeys continued to vocalize spontaneously. In addition, they continued to use hand movements as instructed responses during adulthood. This greater vocal flexibility of monkeys early in ontogeny supports the neoteny hypothesis in human evolution. This suggests that linguistic capabilities were enabled via an expansion of the juvenile period during the development of humans. [ABSTRACT FROM AUTHOR]

One key assumption often inferred with using radio-equipped individuals is that the transmitter has no effect on the metric of interest. To evaluate this assumption, we used a known fate model to assess the effect of transmitter type (i.e. tail-mounted or peritoneal implant) on short-term (one year) survival and a joint live-dead recovery model and results from a mark-recapture study to compare long-term (eight years) survival and body condition of ear-tagged only American beavers Castor canadensis to those equipped with radio transmitters in Voyageurs National Park, Minnesota, USA. Short-term (1-year) survival was not influenced by transmitter type ( wi = 0.64). Over the 8-year study period, annual survival was similar between transmitter-equipped beavers (tail-mounted and implant transmitters combined; 0.76; 95% CI = 0.45-0.91) versus ear-tagged only (0.78; 95% CI = 0.45-0.93). Additionally, we found no difference in weight gain (t9 = 0.25, p = 0.80) or tail area ( t11 = 1.25, p = 0.24) from spring to summer between the two groups. In contrast, winter weight loss (t22 = - 2.03, p = 0.05) and tail area decrease ( t30 = - 3.04, p = 0.01) was greater for transmitterequipped (weight = - 3.09 kg, SE = 0.55; tail area = - 33.71 cm2, SE = 4.80) than ear-tagged only (weight = - 1.80 kg, SE = 0.33; tail area = - 12.38 cm2, SE = 5.13) beavers. Our results generally support the continued use of transmitters on beavers for estimating demographic parameters, although we recommend additional assessments of transmitter effects under different environmental conditions. [ABSTRACT FROM AUTHOR]

Tail-mounted transmitters have been used successfully in temperate regions of North America and Europe but have not been tested in more northern parts of American beaver Castor canadensis range. We deployed 63 tail-mounted transmitters on adult beavers in Voyageurs National Park, Minnesota (USA; 48°30′N, 92°50′W), at the southern edge of the boreal forest. Mean transmitter retention time was 133 days (range = 18-401, SD = 101), with only 7% retained > 12 months. Males and females did not differ in retention times. Retention time was similar for transmitters deployed in fall (n = 38, = 135 days) and spring (n = 21, = 130 days). In 24 cases where we confirmed beavers lost transmitters, 63% tore through the side of the tail, 25% pulled out through a widened attachment hole, and 13% had the lock-nut unscrew. Beavers chewed off or pulled out whip antennas on 50% of transmitters before they were detached from the tail, which reduced VHF signal strength and detection distance. The likelihood that an antenna would be damaged increased 3.8 times for each day of deployment up to 371 days. On average, beavers with transmitters lost 23% of their body mass and 26% of tail thickness over winter, and regained similar percentages over the growing season. Retention rates and retention times of tail transmitters were much lower in Voyageurs National Park relative to more southern areas in the United States where intra-annual variability in body condition is considerably less. Our results reaffirm that methodologies developed for wildlife telemetry or other research and monitoring techniques should be tested under different environmental conditions to ensure objectives can be met in a safe and efficient manner. [ABSTRACT FROM AUTHOR]

Biparental care of offspring occurs in diverse mammalian genera and is particularly common among species with socially monogamous mating systems. Despite numerous well-documented examples, however, the evolutionary causes and consequences of paternal care in mammals are not well understood. Here, we investigate the evolution of paternal care in relation to offspring production. Using comparative analyses to test for evidence of evolutionary associations between male care and life-history traits, we explore if biparental care is likely to have evolved because of the importance of male care to offspring survival, or if evolutionary increases in offspring production are likely to result from the evolution of biparental care. Overall, we find no evidence that paternal care has evolved in response to benefits of supporting females to rear particularly costly large offspring or litters. Rather, our findings suggest that increases in offspring production are more likely to follow the evolution of paternal care, specifically where males contribute depreciable investment such as provisioning young. Through coevolution with litter size, we conclude that paternal care inmammals is likely to play an important role in stabilizing monogamous mating systems and could ultimately promote the evolution of complex social behaviours. [ABSTRACT FROM AUTHOR]

Mammalian genomes typically contain hundreds of thousands of endogenous retroviruses (ERVs), derived from ancient retroviral infections. Using this molecular 'fossil' record, we reconstructed the natural history of a specific retrovirus lineage (ERV-Fc) that disseminated widely between ~33 and ~15 million years ago, corresponding to the Oligocene and early Miocene epochs. Intercontinental viral spread, numerous instances of interspecies transmission and emergence in hosts representing at least 11 mammalian orders, and a significant role for recombination in diversification of this viral lineage were also revealed. By reconstructing the canonical retroviral genes, we identified patterns of adaptation consistent with selection to maintain essential viral protein functions. Our results demonstrate the unique potential of the ERV fossil record for studying the processes of viral spread and emergence as they play out across macro-evolutionary timescales, such that looking back in time may prove insightful for predicting the long-term consequences of newly emerging viral infections. [ABSTRACT FROM AUTHOR]

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For both humans and other animals, the ability to combine information obtained through different senses is fundamental to the perception of the environment. It is well established that humans form systematic cross-modal correspondences between stimulus features that can facilitate the accurate combination of sensory percepts. However, the evolutionary origins of the perceptual and cognitive mechanisms involved in these cross-modal associations remain surprisingly underexplored. In this review we outline recent comparative studies investigating how non-human mammals naturally combine information encoded in different sensory modalities during communication. The results of these behavioural studies demonstrate that various mammalian species are able to combine signals from different sensory channels when they are perceived to share the same basic features, either because they can be redundantly sensed and/or because they are processed in the same way. Moreover, evidence that a wide range of mammals form complex cognitive representations about signallers, both within and across species, suggests that animals also learn to associate different sensory features which regularly co-occur. Further research is now necessary to determine how multisensory representations are formed in individual animals, including the relative importance of low level feature-related correspondences. Such investigations will generate important insights into how animals perceive and categorise their environment, as well as provide an essential basis for understanding the evolution of multisensory perception in humans. [ABSTRACT FROM AUTHOR]

A commercially available fisheries sonar was mounted on an icebreaker and evaluated during an environmental baseline study in the Canadian Beaufort Sea, to determine the applicability of active acoustic monitoring (AAM) for marine mammal detection by comparing marine mammal observer (MMO) visual sightings and active acoustic detections. During 170 h of simultaneous MMO and AAM, 115 bowhead whales (Balaena mysticetus) and four beluga whales (Delphinapterus leucas) were visually sighted by MMOs, while 59 sonar detections of bowhead whales occurred using AAM. The fisheries sonar detected 92% of the cetaceans observed within 2,000 m. Additional observations of ringed seals (Pusa hispida) and bearded seals (Erignathus barbatus) were recorded both by MMOs and AAM. Comparative results indicate that a commercially available active acoustic system can consistently detect marine mammals within varying ranges dictated by water column properties. Shallow environments and strong pycnoclines currently present challenges to AAM. [ABSTRACT FROM AUTHOR]