Abstract: Equine vocalization and acoustic sounds can communicate a horse’s emotional state, physiological state, and situation to other individuals, including other horses and humans. These vocalizations and acoustic sounds can be divided into several types. The whinny, nicker, squeal, blow, snore, snort, roar, and groan are typical types of horse vocalizations and acoustic sounds. The sound localization thresholds of horses are markedly poorer than those of other large mammals, such as humans and elephants. The audiogram of horse has shown their best sensitivity and hearing range in which it perceives sound. Laryngeal diseases, such as laryngeal hemiplegia, dorsal displacement of the soft palate, and alar fold paralysis, can cause laryngeal sounds in the upper airway. The analyses of horses’ vocalizations and laryngeal sounds that are reviewed in this article were conducted with computer-aided analysis programs using spectrograms and spectra that evaluate several parameters, including amplitude, fundamental frequency, duration, and formants. Laryngeal sound analysis could be a useful method for diagnosing upper airway diseases. This article presents a review of the literature describing scientific analyses of horse vocalizations and acoustic sounds to elucidate equine acoustic communications and aid in the development of horse-human bonds.

Abstract: Recent research with cotton-top tamarin monkeys has revealed language discrimination abilities similar to those found in human infants, demonstrating that these perceptual abilities are not unique to humans but are also present in non-human primates. Specifically, tamarins could discriminate forward but not backward sentences of Dutch from Japanese, using both natural and synthesized utterances. The present study was designed as a conceptual replication of the work on tamarins. Results show that rats trained in a discrimination learning task readily discriminate forward, but not backward sentences of Dutch from Japanese; the results are particularly robust for synthetic utterances, a pattern that shows greater parallels with newborns than with tamarins. Our results extend the claims made in the research with tamarins that the capacity to discriminate languages from different rhythmic classes depends on general perceptual abilities that evolved at least as far back as the rodents.

Abstract: Marten and Psarakos have presented some evidence which suggests that objective self-awareness and possibly representations of self may characterize the dolphins' experience of self. Their research demonstrates the possibility of similarities in the sense of self between primate species and dolphins, although whether dolphins have subjective self-awareness, personal memories, and theories of self--all important facets of the sense of self in humans--was not examined. Clearly, even this limited evidence was difficult to achieve; the difficulties in adapting methods and coding behavior are quite apparent in their report. Future progress, however, may depend upon clarification of what are the necessary components for a sense of self and an explication of how these might be reflected in dolphin behavior. We are mindful of the authors' point (pp. 219 and 220) that the dolphin lives more in an acoustic than a visual environment. Thus, while tasks relying upon vision may reveal the presence or absence of the sense of self in primates, it might well be the case that in dolphins self-related experiences might be better revealed in auditory tasks. But then, what is the nature of human self-awareness in terms of audition? While both conceptual and methodological hurdles remain, Marten and Psarakos have demonstrated that important questions can be asked about the minds and phenomenal worlds of nonanthropoid species.

Abstract: In mirror mark tests dolphins twist, posture, and engage in open-mouth and head movements, often repetitive. Because postures and an open mouth are also dolphin social behaviors, we used self-view television as a manipulatable mirror to distinguish between self-examination and social behavior. Two dolphins were exposed to alternating real-time self-view (“mirror mode”) and playback of the same to determine if they distinguished between them. The adult male engaged in elaborate open-mouth behaviors in mirror mode, but usually just watched when played back the same material. Mirror mode behavior was also compared to interacting with real dolphins (controls). Mark tests were conducted, as well as switches from front to side self-views to see if the dolphins turned. They presented marked areas to the self-view television and turned. The results suggest self-examination over social behavior.

Abstract: Vagrant non-breeding ravens frequently attract conspecifics to rich ephemeral food sources. There, grouping may allow them to overcome the defence of territorial breeders. Here, we focus on ravens making use of regular food supplies in a game park, where they divert food from the provision of park animals. We investigated if ravens foraging in the Cumberland game park (Grünau, Austria) are attentive towards one another when they experience some unpredictability in food provisioning. We confronted a group of 30-50 ravens with two different treatments. Ten minutes ahead of the feeding of either wolves or wild boars we showed buckets containing pieces of meat to the ravens flying overhead. In the reliable cue treatment (RCT), the meat was placed next to one of the two enclosures, whereas in the unreliable cue treatment (UCT), the buckets were placed simultaneously in front of both enclosures though only in one of the enclosures were the animals fed 10 min later. Thus, during RCT but not during UCT, ravens could predict where food would become available. Only during UCT, ravens moved in large groups between the two feeding sites. Many ravens moving at the same time in the same direction may indicate some co-ordination in space and time, which is most likely achieved by social attraction among individuals. Furthermore, the number of ravens approaching and leaving, respectively, a feeding site cross-correlated with a temporary increase in the rate of a food-associated call, the yell. This suggests that in addition to watching each other, calling may have contributed to group formation. Possible benefits of group formation during food inspection are discussed.