Observations of Rough-Toothed Dolphins (Steno bredanensis) off the Coast of Utila, Honduras

Local dive shop operators and fishermen report that rough-toothed dolphins (Steno bredanensis) are frequently encountered off the coast of Utila, Honduras, (16°05\u2746.5 N 86°55\u2747.8 W). Our observations suggest that at least some of these animals may constitute a resident population, although the extent of the resident group’s home range has not been determined. Twenty-eight rough-toothed dolphins were identified using photoidentification techniques, 15 of which were re-sighted on two or more occasions. The 12 animals that were re-sighted four or more times were typically seen together, suggesting that they constitute a stable social group. At least one of these dolphins is an adult male, and his continued presence in this social group may reflect a social structure for rough-toothed dolphins that differs from that described for other dolphin species. Social interactions often involved tactile behaviours such as pectoral fin rubbing and side rubbing. The observed dolphins sometimes expressed interest in the research vessel and other boats by approaching, and on separate occasions examined a hydrophone and slow moving propeller visually and echoically. Overall, our behavioural observations suggest: (1) synchronous behaviours and ‘tight’ groupings are common while rough-toothed dolphins are travelling; (2) tactile contact is an important aspect of social interactions for rough-toothed dolphins; (3) cooperative behaviour occurs during play; and (4) rough-toothed dolphins are curious

Out of the Mouth of Babes: Lessons from Research on Human Infants

Marine mammal behavior and cognition researchers often face a number of challenges, including the research subjects’ lack of interest and verbal abilities, as well as choosing a paradigm with appropriate stimuli for the subjects’ perceptual and cognitive abilities. Researchers who work with human infants often encounter similar challenges when studying infant cognition and have developed strategies to overcome these challenges, including using stimuli that capture the infants’ attention, determining what tasks are age-appropriate, and using conditioned responses to test discrimination abilities. This paper encourages marine mammal researchers to learn from the research paradigms and techniques used in human infant research and alter them appropriately for the intended study subjects. The conditioned head-turn response, Violation-of-Expectation paradigm, and the help/hinder paradigm have all been used in infant cognition research and show great promise for furthering the current understanding of marine mammal behavior and cognition. In addition, studying a subject’s spontaneous behavior can provide valuable insight in areas such as problem solving skills, creativity, and individual differences. Care must be taken to adapt the paradigms and use stimuli to fit each species’ perceptual abilities. For example, avoiding a task that requires color discrimination for species that do not possess color vision or using stimuli that fall within a particular species’ hearing range are necessary steps in designing an ecologically valid and informative study. Adapting paradigms previously used with human infants can help expand the current understanding of marine mammal communication, cognitive abilities, and social behavior

Compositional Differences, Functional Similarities: A Linguistic Analysis of Private Speech from a Young Child and a Home-Reared African Grey Parrot (Psittacus erithacus erithacus)

Humans and other vocal-learning species engage in solo vocalizations. Such vocalizations in the human literature are referred to as private speech and have been hypothesized to play a role in vocal repertoire development both in humans and nonhumans, alike. The current study used corpus linguistics techniques to quantitatively and qualitatively compare the private speech of a two-year-old child and an enculturated, home-reared African Grey parrot to identify similarities and differences in the composition and function of their private speech. Both speakers exhibited previously documented human private speech functions, including sound- and word-play and repetitive practice of new words. The composition of the utterances, however, was different between the two speakers. The child’s private speech contained a larger vocabulary, more frequent use of function words (i.e., prepositions, articles, pronouns, conjunctions) to string together ideas, and the use of multiple verb tenses. The cross-species finding that a home-reared parrot’s private speech is similar in function—including evidence of play and possible intrinsically-motivated practice—to that of a language-learning child offers unique insights into the evolution of human language.&nbsp

How Selective is Social Learning in Dolphins?

Social learning is an important aspect of dolphin social life and dolphin behavioral development. In addition to vocal social learning, dolphins discover behaviors for foraging, play, and social interactions by observing other members of their social group. But dolphins neither indiscriminately observe nor mindlessly mimic other dolphins. To the contrary, dolphin calves are quite selective in their choices of who to observe and/or imitate. Calves are most likely to learn foraging behaviors from their mothers, but they are more likely to watch and reproduce the play behaviors of other calves than the play behaviors of adult dolphins (including their mothers). But not all calves are equally likely to be good models. Instead, calves are more likely to observe and mimic the behaviors of other calves that are producing either novel behaviors or more complex forms of behaviors that the observing calf already knows. As a result, there is a general tendency for calves to watch and learn from calves that are older than they are. But differences in age are only part of the story. In fact, dolphin personality may be more important than dolphin age in determining the efficacy of a model

Does Personality Similarity In Bottlenose Dolphin Pairs Influence Dyadic Bond Characteristics?

Social structures are critical to the success of many species and have repercussions on health, well-being, and adaptation, yet little is known about the factors which shape these structures aside from ecology and life history strategies. Dyadic bonds are the basis of all social structures; however, mechanisms for formations of specific bonds or patterns in which individuals form which types of bonds have yet to be demonstrated. There is a variety of evidence indicating personality may be a factor in shaping bonds, but this relationship has not been explored with respect to bond components and is yet to be demonstrated in dolphins. This study utilizes a captive population in a naturalistic environment to test for correlation between similarity within the dyad along each personality factor and the strength of the dyad\u27s bond characteristics. Personality was assessed using a Five Factor Model questionnaire. Dyadic bond strength and characteristic qualities were determined through an exploratory factor analysis to group behaviors recorded via underwater opportunistic focal-follow video. Discovered bond components differed from previous studies and were termed Affiliative Support, Sociosexual, and Conflict Play. Individuals who differed in Extraversion and Neuroticism and were similar in Conscientiousness displayed greater levels of bonding. This study expands our understanding of the formation of bonds between individuals and the evolution of social structure. Furthermore, it better equips us for making informed environmental policy decisions and improving captive animal care

Humpback whale, Megaptera novaeangliae, song during the breeding season in the Gulf of Tribugá, Colombian Pacific

A key feature of humpback whale behavior, documented primarily on the breeding grounds, is the repertoire of the males’ song. Song is made up of single units combined together into phrases, which are repeated to make up themes. A song consists of several themes sung in succession. This study qualitatively investigates the presence and structure of song recorded in the Gulf of Tribugá in the Colombian Pacific. Data were collected between June and September 201 3, from which approximately 4 hours and 30 minutes of song were analyzed from five individual whales. Three distinct themes, always sung in the same order (theme 1 -theme 2- theme 3) were identified. Theme 1 was the most predominant theme overall, and was present in each song session that was analyzed. The structure of each theme is described with accompanying spectrograms, and specific acoustic parameters further illustrate theme progression and characterize differences between whales. This study serves as the first published descriptive analysis of the song of stock G in this area, and suggestions are made for future directions of investigation. Research on humpback song is used as a part of the overall efforts of Macuáticos Colombia Foundation to educate the communities of the Gulf of Tribugá about the importance of conservation, and to advocate for stricter guidelines for safe whale-watching practices.RÉSUMÉLes baleines à bosse ont été observées dans le monde entier et elles migrent chaque année entre leurs zones de nourrissage dans les latitudes élevées et les aires de reproduction aux latitudes basses. Le chant des baleines à bosse est l’un des comportements lié à l’accouplement qui a été documenté sur les aires de reproduction. Ce chant est composé d'unités simples combinées dans des phrases et qui sont répétées pour composer des thèmes. Les chants sont composés de plusieurs thèmes et sont principalement émis par les mâles. L'étude actuelle a porté sur la présence et la structure du chant des baleines à bosse du G-stock enregistré dans le golfe de Tribugá dans le Pacifique colombien. Les données ont été recueillies entre juin et septembre 201 3 à l'aide d'un hydrophone SQ26-08 au cours d’excursions en bateau qui se sont déroulées 3 fois par semaine. La structure du chant a été codée en utilisant Raven Pro 1 .4. Environ 4 heures et 30 minutes de chant ont été analysées et les chercheurs ont identifié trois thèmes distincts qui ont toujours été entendus dans le même ordre. Le thème 1 dominait dans tous les enregistrements et était composé de répétitions de légères variations de l'expression ‘ABABABAA’. Le thème 2 était composé de répétitions des unités ‘F’ et ‘Bl’, avec des variations de la phrase de multiples unités répétées dans une rangée. Le thème 3 était composé de phrases répétées d'une unité longue ‘upsweep’ tonale 'LU' , suivie par une unité courte ‘upsweep’ tonale ‘SU’, parfois avec une unité ‘downsweep’ dans le motif. L'unité ‘S’ a été entendue pendant les transitions du thème 3 au thème 1 . Le thème 1 a été entendu beaucoup plus fréquemment que les autres thèmes et le thème 3 était le moins fréquemment enregistré. La structure changeante de chaque thème a été décrite avec des spectrogrammes d'accompagnement et les paramètres acoustiques ont été utilisés pour différencier les unités. Cette étude est la première analyse descriptive du chant du stock G dans ce domaine et des suggestions sont proposées pour les orientations futures de l'étude. Les enregistrements sonores ont été utilisés pour soutenir les efforts déployés par la Fondation Macuáticos Colombie pour sensibiliser éduquer les communautés du golfe de Tribugá sur l' importance de la conservation et pour renforcer les directives portant sur les pratiques sécurisées d’observation des baleines et de la pêche

Humpback whale, Megaptera novaeangliae, song during the breeding season in the Gulf of Tribugá, Colombian Pacific

A key feature of humpback whale behavior, documented primarily on the breeding grounds, is the repertoire of the males’ song. Song is made up of single units combined together into phrases, which are repeated to make up themes. A song consists of several themes sung in succession. This study qualitatively investigates the presence and structure of song recorded in the Gulf of Tribugá in the Colombian Pacific. Data were collected between June and September 2013, from which approximately 4 hours and 30 minutes of song were analyzed from five individual whales. Three distinct themes, always sung in the same order (theme 1-theme 2- theme 3) were identified. Theme 1 was the most predominant theme overall, and was present in each song session that was analyzed. The structure of each theme is described with accompanying spectrograms, and specific acoustic parameters further illustrate theme progression and characterize differences between whales. This study serves as the first published descriptive analysis of the song of stock G in this area, and suggestions are made for future directions of investigation. Research on humpback song is used as a part of the overall efforts of Macuáticos Colombia Foundation to educate the communities of the Gulf of Tribugá about the importance of conservation, and to advocate for stricter guidelines for safe whale-watching practices.RÉSUMÉLes baleines à bosse ont été observées dans le monde entier et elles migrent chaque année entre leurs zones de nourrissage dans les latitudes élevées et les aires de reproduction aux latitudes basses. Le chant des baleines à bosse est l’un des comportements lié à l’accouplement qui a été documenté sur les aires de reproduction. Ce chant est composé d'unités simples combinées dans des phrases et qui sont répétées pour composer des thèmes. Les chants sont composés de plusieurs thèmes et sont principalement émis par les mâles. L'étude actuelle a porté sur la présence et la structure du chant des baleines à bosse du G-stock enregistré dans le golfe de Tribugá dans le Pacifique colombien. Les données ont été recueillies entre juin et septembre 2013 à l'aide d'un hydrophone SQ26-08 au cours d’excursions en bateau qui se sont déroulées 3 fois par semaine. La structure du chant a été codée en utilisant Raven Pro 1.4. Environ 4 heures et 30 minutes de chant ont été analysées et les chercheurs ont identifié trois thèmes distincts qui ont toujours été entendus dans le même ordre. Le thème 1 dominait dans tous les enregistrements et était composé de répétitions de légères variations de l'expression ‘ABABABAA’. Le thème 2 était composé de répétitions des unités ‘F’ et ‘Bl’, avec des variations de la phrase de multiples unités répétées dans une rangée. Le thème 3 était composé de phrases répétées d'une unité longue ‘upsweep’ tonale 'LU', suivie par une unité courte ‘upsweep’ tonale ‘SU’, parfois avec une unité ‘downsweep’ dans le motif. L'unité ‘S’ a été entendue pendant les transitions du thème 3 au thème 1. Le thème 1 a été entendu beaucoup plus fréquemment que les autres thèmes et le thème 3 était le moins fréquemment enregistré. La structure changeante de chaque thème a été décrite avec des spectrogrammes d'accompagnement et les paramètres acoustiques ont été utilisés pour différencier les unités. Cette étude est la première analyse descriptive du chant du stock G dans ce domaine et des suggestions sont proposées pour les orientations futures de l'étude. Les enregistrements sonores ont été utilisés pour soutenir les efforts déployés par la Fondation Macuáticos Colombie pour sensibiliser éduquer les communautés du golfe de Tribugá sur l'importance de la conservation et pour renforcer les directives portant sur les pratiques sécurisées d’observation des baleines et de la pêche

Responses to Familiar and Unfamiliar Humans by Belugas (Delphinapterus leucas), Bottlenose Dolphins (Tursiops truncatus), & Pacific White-Sided Dolphins (Lagenorhynchus obliquidens): A Replication and Extension

Previous research has documented that cetaceans can discriminate between humans, but the process used to categorize humans still remains unclear. The goal of the present study was to replicate and extend previous work on the discrimination between familiar and unfamiliar humans by three species of cetaceans. The current study manipulated the familiarity and activity level of humans presented to 12 belugas (Delphinapterus leucas) housed between two facilities, five bottlenose dolphins (Tursiops truncatus), and six Pacific white-sided dolphins (Lagenorhynchus obliquidens) during free-swim conditions. Two measures of discrimination were coded from video recordings of each trial: lateralized visual processing and gaze duration. No clear lateralization effects emerged at the species level, primarily due to extensive individual variability. The results also indicated that activity level influenced gaze durations across species, and for some individuals, the interaction between human familiarity and activity level influenced gaze durations and eye preferences. Unexpectedly, bottlenose dolphins had longer gaze durations for familiar humans whereas belugas and Pacific white-sided dolphins had longer gaze durations for unfamiliar humans. All three groups displayed longer gaze durations for active humans as compared to neutral humans, and belugas and bottlenose dolphins had significantly longer gaze durations than Pacific white-sided dolphins. These results indicate that the cetaceans can discriminate between unfamiliar and familiar humans and preferred active humans. However, discrimination of humans via lateralized visual processing did not appear at the group level, but rather at the individual level which countered previous research. This study is discussed within the contexts of attention and individual differences across animals of different species

Common bottlenose dolphin, Tursiops truncatus, seasonal habitat use and associations with habitat characteristics in Roanoke Sound, North Carolina

Understanding how habitat characteristics influence common bottlenose dolphin, Tursiops truncatus, distribution and behavior can be useful for conservation. The dolphin community in Roanoke Sound, North Carolina primarily exhibits seasonal residency and there is limited information on their habitat use. The objectives of this study were to increase habitat use knowledge and determine the relationship between habitat characteristics and dolphin distribution using standardized photographic-identification data (2009 – 2017). A hot spot (Getis-Ord Gi*) analysis showed dolphins frequently use the southern region containing the mouth of the estuary for feeding and traveling. Habitat characteristics were modeled with zero-altered gamma (ZAG), generalized linear (GLM), and generalized additive (GAM) models to predict dolphin group density. Models showed that groups were more likely to be present in areas with greater benthic slope variation and shallow areas closer to land, and that different habitat characteristics were associated with feed, social, and travel activities. This study suggests that Roanoke Sound provides a seasonal foraging area and travel corridor between the estuaries and coastal waters. This information contributes baseline knowledge of how habitat potentially influences dolphin distribution and behavior which can be useful for management and conservation, especially in areas where habitat changes and impacts need to be assessed