A Note on Suckling Behavior and Laterality in Nursing Humpback Whale Calves from Underwater Observations.
Ontology highlight
ABSTRACT:
SUBMITTER: Zoidis AM
PROVIDER: S-EPMC5532566 | biostudies-other | 2017 Jul
REPOSITORIES: biostudies-other
Similar Datasets
Project description:Getting maternal milk through nursing is vital for all newborn mammals. Despite its importance, nursing has been poorly documented in humpback whales (Megaptera novaeangliae). Nursing is difficult to observe underwater without disturbing the whales and is usually impossible to observe from a ship. We attempted to observe nursing from the calf's perspective by placing CATS cam tags on three humpback whale calves in the Sainte Marie channel, Madagascar, Indian Ocean, during the breeding seasons. CATS cam tags are animal-borne multi-sensor tags equipped with a video camera, a hydrophone, and several auxiliary sensors (including a 3-axis accelerometer, a 3-axis magnetometer, and a depth sensor). The use of multi-sensor tags minimized potential disturbance from human presence. A total of 10.52 h of video recordings were collected with the corresponding auxiliary data. Video recordings were manually analyzed and correlated with the auxiliary data, allowing us to extract different kinematic features including the depth rate, speed, Fluke Stroke Rate (FSR), Overall Body Dynamic Acceleration (ODBA), pitch, roll, and roll rate. We found that suckling events lasted 18.8 ± 8.8 s on average (N = 34) and were performed mostly during dives. Suckling events represented 1.7% of the total observation time. During suckling, the calves were visually estimated to be at a 30-45° pitch angle relative to the midline of their mother's body and were always observed rolling either to the right or to the left. In our auxiliary dataset, we confirmed that suckling behavior was primarily characterized by a high average absolute roll and additionally we also found that it was likely characterized by a high average FSR and a low average speed. Kinematic features were used for supervised machine learning in order to subsequently detect suckling behavior automatically. Our study is a proof of method on which future investigations can build upon. It opens new opportunities for further investigation of suckling behavior in humpback whales and the baleen whale species.
| S-EPMC8858581 | biostudies-literature
Project description:Nursing influences growth rate and overall health of mammals; however, the behavior is difficult to study in wild cetaceans because it occurs below the surface and can thus be misidentified from surface observations. Nursing has been observed in humpback whales on the breeding and calving grounds, but the behavior remains unstudied on the feeding grounds. We instrumented three dependent calves (four total deployments) with combined video and 3D-accelerometer data loggers (CATS) on two United States feeding grounds to document nursing events. Two associated mothers were also tagged to determine if behavior diagnostic of nursing was evident in the mother's movement. Animal-borne video was manually analyzed and the average duration of successful nursing events was 23 s (±7 sd, n = 11). Nursing occurred at depths between 4.1-64.4 m (along the seafloor) and in close temporal proximity to foraging events by the mothers, but could not be predicted solely by relative positions of mother and calf. When combining all calf deployments, successful nursing was documented eleven times; totaling only 0.3% of 21.0 hours of video. During nursing events, calves had higher overall dynamic body acceleration (ODBA) and increased fluke-stroke rate (FSR) compared to non-nursing segments (Mixed effect models, ODBA: F1,107 = 13.57756, p = 0.0004, FSR: F1,107 = 32.31018, p < 0.0001). In contrast, mothers had lower ODBA and reduced FSR during nursing events compared to non-nursing segments. These data provide the first characterization of accelerometer data of humpback whale nursing confirmed by animal-borne video tags and the first analysis of nursing events on feeding grounds. This is an important step in understanding the energetic consequences of lactation while foraging.
| S-EPMC7060748 | biostudies-literature
Project description:Reports of humpback whale (Megaptera novaeangliae) song chorusing occurring outside the breeding grounds are becoming more common, but song structure and underwater behavior of individual singers on feeding grounds and migration routes remain unknown. Here, ten humpback whales in the Western Antarctic Peninsula were tagged in May 2010 with non-invasive, suction-cup attached tags to study foraging ecology and acoustic behavior. Background song was identified on all ten records, but additionally, acoustic records of two whales showed intense and continuous singing, with a level of organization and structure approaching that of typical breeding ground song. The songs, produced either by the tagged animals or close associates, shared phrase types and theme structure with one another, and some song bouts lasted close to an hour. Dive behavior of tagged animals during the time of sound production showed song occurring during periods of active diving, sometimes to depths greater than 100 m. One tag record also contained song in the presence of feeding lunges identified from the behavioral sensors, indicating that mating displays occur in areas worthy of foraging. These data show behavioral flexibility as the humpbacks manage competing needs to continue to feed and to prepare for the breeding season during late fall. This may also signify an ability to engage in breeding activities outside of the traditional, warm water breeding ground locations.
| S-EPMC3526533 | biostudies-literature
Project description:Acoustic communication is important for animals with dependent young, particularly when they are spatially separated. Maternal humpback whales (Megaptera novaeangliae) use acoustic calling to help minimize the risk of separation from their young calves during migration. These pairs also use acoustic crypsis to minimize detection by males. How they balance a restricted active space with the need to maintain acoustic contact during periods of separation is not yet understood. Here, we analyzed movement metrics of tagged adult female-calf pairs during migration to identify two behavioral states, "resting/milling" and "travelling." When travelling, these pairs dived synchronously and exhibited little to no spatial separation. Alternatively, adult females had significantly longer dive durations (p < .01) when resting, and while they spent prolonged times at depth, calves would surface several times independently. This demonstrated that these pairs are frequently separated during periods of rest. We then determined whether the call rates and acoustic levels of these pairs increased with more frequent separation, finding that both adult females and calves significantly increased their call rates, but not levels, when resting. We also found that adult female-calf pairs have a restricted active space, with less than 15% of calls estimated to be detectable beyond 2 km. However, as with call level, detection distance did not differ significantly between the two behavioral states. In summary, adult female-calf pairs maintain successful communication during periods of separation by calling more frequently rather than by producing louder calls. This strategy aids in maintaining acoustic contact while simultaneously limiting detectability by conspecifics.
| S-EPMC8826064 | biostudies-literature
Project description:Humpback whale song is an extraordinary example of vocal cultural behaviour. In northern populations, the complex songs show long-lasting traditions that slowly evolve, while in the South Pacific, periodic revolutions occur when songs are adopted from neighbouring populations and rapidly spread. In this species, vocal learning cannot be studied in the laboratory, learning is instead inferred from the songs' complexity and patterns of transmission. Here, we used individual-based cultural evolutionary simulations of the entire Southern and Northern Hemisphere humpback whale populations to formalize this process of inference. We modelled processes of song mutation and patterns of contact among populations and compared our model with patterns of song theme sharing measured in South Pacific populations. Low levels of mutation in combination with rare population interactions were sufficient to closely fit the pattern of diversity in the South Pacific, including the distinctive pattern of west-to-east revolutions. Interestingly, the same learning parameters that gave rise to revolutions in the Southern Hemisphere simulations gave rise to evolutionary patterns of cultural evolution in the Northern Hemisphere populations. Our study demonstrates how cultural evolutionary approaches can be used to make inferences about the learning processes underlying cultural transmission and how they might generate emergent population-level processes. This article is part of the theme issue 'Vocal learning in animals and humans'.
| S-EPMC8419575 | biostudies-literature
Project description:Why do humpback whales sing? This paper considers the hypothesis that humpback whales may use song for long range sonar. Given the vocal and social behavior of humpback whales, in several cases it is not apparent how they monitor the movements of distant whales or prey concentrations. Unless distant animals produce sounds, humpback whales are unlikely to be aware of their presence or actions. Some field observations are strongly suggestive of the use of song as sonar. Humpback whales sometimes stop singing and then rapidly approach distant whales in cases where sound production by those whales is not apparent, and singers sometimes alternately sing and swim while attempting to intercept another whale that is swimming evasively. In the evolutionary development of modern cetaceans, perceptual mechanisms have shifted from reliance on visual scanning to the active generation and monitoring of echoes. It is hypothesized that as the size and distance of relevant events increased, humpback whales developed adaptive specializations for long-distance echolocation. Differences between use of songs by humpback whales and use of sonar by other echolocating species are discussed, as are similarities between bat echolocation and singing by humpback whales. Singing humpback whales are known to emit sounds intense enough to generate echoes at long ranges, and to flexibly control the timing and qualities of produced sounds. The major problem for the hypothesis is the lack of recordings of echoes from other whales arriving at singers immediately before they initiate actions related to those whales. An earlier model of echoic processing by singing humpback whales is here revised to incorporate recent discoveries. According to the revised model, both direct echoes from targets and modulations in song-generated reverberation can provide singers with information that can help them make decisions about future actions related to mating, traveling, and foraging. The model identifies acoustic and structural features produced by singing humpback whales that may facilitate a singer's ability to interpret changes in echoic scenes and suggests that interactive signal coordination by singing whales may help them to avoid mutual interference. Specific, testable predictions of the model are presented.
| S-EPMC6055024 | biostudies-other
Project description:Cultural transmission of behaviour is important in a wide variety of vertebrate taxa from birds to humans. Vocal traditions and vocal learning provide a strong foundation for studying culture and its transmission in both humans and cetaceans. Male humpback whales (Megaptera novaeangliae) perform complex, culturally transmitted song displays that can change both evolutionarily (through accumulations of small changes) or revolutionarily (where a population rapidly adopts a novel song). The degree of coordination and conformity underlying song revolutions makes their study of particular interest. Acoustic contact on migratory routes may provide a mechanism for cultural revolutions of song, yet these areas of contact remain uncertain. Here, we compared songs recorded from the Kermadec Islands, a recently discovered migratory stopover, to multiple South Pacific wintering grounds. Similarities in song themes from the Kermadec Islands and multiple wintering locations (from New Caledonia across to the Cook Islands) suggest a location allowing cultural transmission of song eastward across the South Pacific, active song learning (hybrid songs) and the potential for cultural convergence after acoustic isolation at the wintering grounds. As with the correlations in humans between genes, communication and migration, the migration patterns of humpback whales are written into their songs.
| S-EPMC6774987 | biostudies-literature
Project description:Humpback whales (Megaptera novaeangliae) have exceptionally long pectorals (i.e. flippers) that aid in shallow water navigation, rapid acceleration and increased manoeuvrability. The use of pectorals to herd or manipulate prey has been hypothesized since the 1930s. We combined new technology and a unique viewing platform to document the additional use of pectorals to aggregate prey during foraging events. Here, we provide a description of 'pectoral herding' and explore the conditions that may promote this innovative foraging behaviour. Specifically, we analysed aerial videos and photographic sequences to assess the function of pectorals during feeding events near salmon hatchery release sites in Southeast Alaska (2016-2018). We observed the use of solo bubble-nets to initially corral prey, followed by calculated movements to establish a secondary boundary with the pectorals-further condensing prey and increasing foraging efficiency. We found three ways in which humpback whales use pectorals to herd prey: (i) create a physical barrier to prevent evasion, (ii) cause water motion to guide prey towards the mouth, and (iii) position the ventral side to reflect light and alter prey movement. Our findings suggest that behavioural plasticity may aid foraging in changing environments and shifts in prey availability. Further study would clarify if 'pectoral herding' is used as a principal foraging tool by the broader humpback whale population and the conditions that promote its use.
| S-EPMC6837203 | biostudies-literature
Project description:Predator diets are largely influenced by prey availability and abundance. Yet, in heterogenous marine environments, identifying the prey species consumed by diving mammals remains a fundamental challenge. For rorqual whales, the energetic constraints of prey engulfment require that the whales seek areas of high prey abundance and execute discrete lunge feeding events on patches of high-density prey. Prey occurrences in feces should therefore provide meaningful insight into the dominant taxa in food patches selected by the animal. We investigated the prey consumed by humpback whales in three regions in southern British Columbia (BC), Canada, using opportunistic fecal sampling, microscopy, and DNA metabarcoding of 14 fecal samples. Fish including Pacific herring (Clupea pallasii), hake (Merluccius productus), and eulachon (Thaleichthys pacificus) were the most common fish species potentially targeted by humpback whales in two regions. The krill Euphausia pacifica was the most prevalent invertebrate DNA detected in all three regions, while sergestid and mysid shrimp may also be important. High DNA read abundances from walleye pollock (Gadus chalcogrammus) and sablefish (Anoplopoma fimbria) were also recovered in one sample each, suggesting that juveniles of these semi-pelagic species may occasionally be targeted. In general, we observed heavily digested fecal material that drove substantial dissimilarities in taxonomic resolution between polymerase chain reaction-based and morphological analyses of the feces. Pacific herring and walleye pollock were the only prey species confirmed by both methods. Our results highlight that molecular and visual analyses of fecal samples provide a complementary approach to diet analysis, with each method providing unique insight into prey diversity.
| S-EPMC9797768 | biostudies-literature
Project description:Noise from shipping activity in North Atlantic coastal waters has been steadily increasing and is an area of growing conservation concern, as it has the potential to disrupt the behaviour of marine organisms. This study examines the impacts of ship noise on bottom foraging humpback whales (Megaptera novaeangliae) in the western North Atlantic. Data were collected from 10 foraging whales using non-invasive archival tags that simultaneously recorded underwater movements and the acoustic environment at the whale. Using mixed models, we assess the effects of ship noise on seven parameters of their feeding behaviours. Independent variables included the presence or absence of ship noise and the received level of ship noise at the whale. We found significant effects on foraging, including slower descent rates and fewer side-roll feeding events per dive with increasing ship noise. During 5 of 18 ship passages, dives without side-rolls were observed. These findings indicate that humpback whales on Stellwagen Bank, an area with chronically elevated levels of shipping traffic, significantly change foraging activity when exposed to high levels of ship noise. This measureable reduction in within-dive foraging effort of individual whales could potentially lead to population-level impacts of shipping noise on baleen whale foraging success.
| S-EPMC5014013 | biostudies-literature