scholarly journals Calves as social hubs: dynamics of the social network within sperm whale units

2013 ◽  
Vol 280 (1763) ◽  
pp. 20131113 ◽  
Author(s):  
Shane Gero ◽  
Jonathan Gordon ◽  
Hal Whitehead
Keyword(s):  
Social Relationships ◽  
Social Role ◽  
Group Formation ◽  
Time Lag ◽  
Group Living ◽  
Sperm Whale ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Social Unit ◽  
The Social

It is hypothesized that the primary function of permanent social relationships among female sperm whales ( Physeter macrocephalus ) is to provide allomothers for calves at the surface while mothers make foraging dives. In order to investigate how reciprocity of allocare within units of sperm whales facilitates group living, we constructed weighted social networks based on yearly matrices of associations (2005–2010) and correlated them across years, through changes in age and social role, to study changes in social relationships within seven sperm whale units. Pairs of association matrices from sequential years showed a greater positive correlation than expected by chance, but as the time lag increased, the correlation coefficients decreased. Over all units considered, calves had high values for all measured network statistics, while mothers had intermediate values for most of the measures, but high values for connectedness and affinity. Mothers showed sharp drops in strength and connectedness in the first year of their new calves' lives. These broad patterns appear to be consistent across units. Calves appeared to be significant nodes in the network of the social unit, and thus provide quantitative support for the theory in which communal care acts as the evolutionary force behind group formation in this species.

scholarly journals Long-term associations among male sperm whales (Physeter macrocephalus)

PLoS ONE ◽  
2020 ◽  
Vol 15 (12) ◽  
pp. e0244204
Author(s):  
Hayao Kobayashi ◽  
Hal Whitehead ◽  
Masao Amano
Keyword(s):  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Association Rate ◽  
Photo Identification ◽  
Male Sperm ◽  
The Social ◽  
Pelagic Habitat ◽  
Best Fitting ◽  
Social Associations

Little is known about the social structure of male sperm whales (Physeter macrocephalus) after they leave their natal units. While previous studies found no evidence for preferred associations among males, the observation of mass-strandings consisting exclusively of males, suggest that they have strong social bonds. To investigate the social associations among male sperm whales, we used half weight index of association, permutation tests and standardized lagged association rate models on a large photo-identification database collected between 2006 and 2017 in Nemuro Strait, Japan. Our results suggest that while male sperm whales are not as social as females, they do form long term associations, have preferred companionship, and forage in social proximity to each other. The best-fitting model to the standardized lagged association rate showed that associations among males last for at least 2.7 years and as most males leave the area after 2 years, associations may last for longer. Twenty dyads were observed associating over more than 2 years, for a maximum 5 years. One dyad was observed associating on 19 different days and clustered on 7 different days. Male associations may function to enhance foraging or to fend off predators. Such relationships seem to be adapted to a pelagic habitat with uncertain resource availability and predation pressure.

scholarly journals Architecture of the sperm whale forehead facilitates ramming combat

PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1895 ◽  
Author(s):  
Olga Panagiotopoulou ◽  
Panagiotis Spyridis ◽  
Hyab Mehari Abraha ◽  
David R. Carrier ◽  
Todd C. Pataky
Keyword(s):  
Connective Tissue ◽  
Structural Engineering ◽  
Sperm Whale ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Moby Dick ◽  
Unique Structure ◽  
Complex Structural ◽  
Von Mises ◽  
Von Mises Stresses

Herman Melville’s novelMoby Dickwas inspired by historical instances in which large sperm whales (Physeter macrocephalus L.) sank 19th century whaling ships by ramming them with their foreheads. The immense forehead of sperm whales is possibly the largest, and one of the strangest, anatomical structures in the animal kingdom. It contains two large oil-filled compartments, known as the “spermaceti organ” and “junk,” that constitute up to one-quarter of body mass and extend one-third of the total length of the whale. Recognized as playing an important role in echolocation, previous studies have also attributed the complex structural configuration of the spermaceti organ and junk to acoustic sexual selection, acoustic prey debilitation, buoyancy control, and aggressive ramming. Of these additional suggested functions, ramming remains the most controversial, and the potential mechanical roles of the structural components of the spermaceti organ and junk in ramming remain untested. Here we explore the aggressive ramming hypothesis using a novel combination of structural engineering principles and probabilistic simulation to determine if the unique structure of the junk significantly reduces stress in the skull during quasi-static impact. Our analyses indicate that the connective tissue partitions in the junk reduce von Mises stresses across the skull and that the load-redistribution functionality of the former is insensitive to moderate variation in tissue material parameters, the thickness of the partitions, and variations in the location and angle of the applied load. Absence of the connective tissue partitions increases skull stresses, particularly in the rostral aspect of the upper jaw, further hinting of the important role the architecture of the junk may play in ramming events. Our study also found that impact loads on the spermaceti organ generate lower skull stresses than an impact on the junk. Nevertheless, whilst an impact on the spermaceti organ would reduce skull stresses, it would also cause high compressive stresses on the anterior aspect of the organ and the connective tissue case, possibly making these structures more prone to failure. This outcome, coupled with the facts that the spermaceti organ houses sensitive and essential sonar producing structures and the rostral portion of junk, rather than the spermaceti organ, is frequently a site of significant scarring in mature males suggest that whales avoid impact with the spermaceti organ. Although the unique structure of the junk certainly serves multiple functions, our results are consistent with the hypothesis that the structure also evolved to function as a massive battering ram during male-male competition.

scholarly journals Socially segregated, sympatric sperm whale clans in the Atlantic Ocean

2016 ◽  
Vol 3 (6) ◽  
pp. 160061 ◽  
Author(s):  
Shane Gero ◽  
Anne Bøttcher ◽  
Hal Whitehead ◽  
Peter Teglberg Madsen
Keyword(s):  
Social Interactions ◽  
Sperm Whale ◽  
Mantel Test ◽  
Good Evidence ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Sympatric Populations ◽  
The Pacific ◽  
Matrix Correlation ◽  
Social Units

Sperm whales ( Physeter macrocephalus ) are unusual in that there is good evidence for sympatric populations with distinct culturally determined behaviour, including potential acoustic markers of the population division. In the Pacific, socially segregated, vocal clans with distinct dialects coexist; by contrast, geographical variation in vocal repertoire in the Atlantic has been attributed to drift. We examine networks of acoustic repertoire similarity and social interactions for 11 social units in the Eastern Caribbean. We find the presence of two socially segregated, sympatric vocal clans whose dialects differ significantly both in terms of categorical coda types produced by each clan (Mantel test between clans: matrix correlation = 0.256; p  ≤ 0.001) and when using classification-free similarity which ignores defined types (Mantel test between clans: matrix correlation = 0.180; p  ≤ 0.001). The more common of the two clans makes a characteristic 1 + 1 + 3 coda, while the other less often sighted clan makes predominantly regular codas. Units were only observed associating with other units within their vocal clan. This study demonstrates that sympatric vocal clans do exist in the Atlantic, that they define a higher order level of social organization as they do in the Pacific, and suggests that cultural identity at the clan level is probably important in this species worldwide.

scholarly journals Social relationships and reproductive performance in group-living arctic blue foxes

1994 ◽  
Vol 3 (1) ◽  
pp. 49-58 ◽  
Author(s):  
Hannu Korhonen ◽  
Sakari Alasuutari
Keyword(s):  
Social Relationships ◽  
Breeding Season ◽  
Group Composition ◽  
Group Living ◽  
Reproductive Behaviour ◽  
Genetic Origin ◽  
Social Contacts ◽  
The Social ◽  
Body Weights ◽  
Blue Fox

The aim of the present work was to study social relationships and reproductivity in captive arctic blue fox groups of different genetic origin. The social status of the individuals among groups remained constant during autumn and early winter. Males typically dominated over females in the groups. Males also had higher body weights and more social contacts than females. The locomotor activity of the animals increased during the breeding season, especially in the case of males. Urinary marking had a significant importance during the breeding season, being most pronounced in dominant males. No synchronization was observed in the heat development of females despite some kinship. Behaviours such as escape attempts, bitings and increased aggressiveness occurred in March-April as a result of increasing social tension combined with reproductive behaviour. Whelping success varied depending on group composition. Some of the non-breeding and breeding females were observed to act as communal nursing helpers.

scholarly journals DNA preserved in jetsam whale ambergris

2020 ◽  
Vol 16 (2) ◽  
pp. 20190819 ◽  
Author(s):  
Ruairidh Macleod ◽  
Mikkel-Holger S. Sinding ◽  
Morten Tange Olsen ◽  
Matthew J. Collins ◽  
Steven J. Rowland
Keyword(s):  
Natural Product ◽  
Dna Sequences ◽  
Reference Data ◽  
Nuclear Genome ◽  
Indirect Evidence ◽  
Sperm Whale ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Ecological Mechanisms

Jetsam ambergris, found on beaches worldwide, has always been assumed to originate as a natural product of sperm whales (Physeteroidea). However, only indirect evidence has ever been produced for this, such as the presence of whale prey remains in ambergris. Here, we extracted and analysed DNA sequences from jetsam ambergris from beaches in New Zealand and Sri Lanka, and sequences from ambergris of a sperm whale beached in The Netherlands. The lipid-rich composition of ambergris facilitated high preservation-quality of endogenous DNA, upon which we performed shotgun Illumina sequencing. Alignment of mitochondrial and nuclear genome sequences with open-access reference data for multiple whale species confirms that all three jetsam samples derived originally from sperm whales ( Physeter macrocephalus ). Shotgun sequencing here also provides implications for metagenomic insights into ambergris-preserved DNA. These results demonstrate significant implications for elucidating the origins of jetsam ambergris as a prized natural product, and also for the understanding of sperm whale metabolism and diet, and the ecological mechanisms underlying these coproliths.

Sperm whale social units: variation and change

1998 ◽  
Vol 76 (8) ◽  
pp. 1431-1440 ◽  
Author(s):  
Jenny Christal ◽  
Hal Whitehead ◽  
Erland Lettevall
Keyword(s):  
Cost Benefit ◽  
Sperm Whale ◽  
Physeter Macrocephalus ◽  
Unit Size ◽  
Social Unit ◽  
Demographic Processes ◽  
Size Variability ◽  
The Cost ◽  
Social Units

Sperm whale (Physeter macrocephalus) photoidentification data spanning 12 years of study around the Galápagos Islands were examined to investigate the size, variability, and stability of social units. Adult females and immature whales of both sexes have two types of associates: "constant companions," which are members of an individual's "stable" social unit, and "casual acquaintances," which are temporarily associating members of different units. We analysed long-term association patterns and calculated that individuals have a mean of 11.3 constant companions. Estimated social unit size ranged from 3 to 24 individuals. Evidence of splitting and merging of units and of transfer of individuals between units is presented. The estimated overall frequency of these unit-membership changes is 6.3% per individual per year. These forms of unit dynamics are rare in species with male dispersal and matrilineally related social groups, and cannot be easily explained in this species. There is considerable variation in unit size (perhaps caused by demographic processes), suggesting that the benefits of remaining in a social unit usually outweigh selection for some optimal unit size. However, the occurrence of merging and transfers suggests that the ecological or social cost/benefit of leaving one's matrilineal unit may sometimes outweigh the cost/benefit of staying.

scholarly journals The nose of the sperm whale: overviews of functional design, structural homologies and evolution

2014 ◽  
Vol 96 (4) ◽  
pp. 783-806 ◽  
Author(s):  
Stefan Huggenberger ◽  
Michel André ◽  
Helmut H. A. Oelschläger
Keyword(s):  
Sperm Whale ◽  
Pulse Generation ◽  
Nasal Passage ◽  
Generation Process ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Acoustic Window ◽  
Deep Diving ◽  
Toothed Whale ◽  
Fat Bodies

The hypertrophic and much elongated epicranial (nasal) complex of sperm whales (Physeter macrocephalus) is a unique device to increase directionality and source levels of echolocation clicks in aquatic environments. The size and shape of the nasal fat bodies as well as the peculiar organization of the air sac system in the nasal sound generator of sperm whales are in favour of this proposed specialized acoustic function. The morphology of the sperm whale nose, including a ‘connecting acoustic window’ in the case and an anterior ‘terminal acoustic window’ at the rostroventral edge of the junk, supports the ‘bent horn hypothesis’ of sound emission. In contrast to the laryngeal mechanism described for dolphins and porpoises, sperm whales may drive the initial pulse generation process with air pressurized by nasal muscles associated with the right nasal passage (right nasal passage muscle, maxillonasolabialis muscle). This can be interpreted as an adaptation to deep-diving and high hydrostatic pressures constraining pneumatic phonation. Comparison of nasal structures in sperm whales and other toothed whales reveals that the existing air sac system as well as the fat bodies and the musculature have the same topographical relations and thus may be homologous in all toothed whales (Odontoceti). This implies that the nasal sound generating system evolved only once during toothed whale evolution and, more specifically, that the unique hypertrophied nasal complex was a main driving force in the evolution of the sperm whale taxon.

Coda communication by sperm whales (Physeter macrocephalus) off the Galápagos Islands

1993 ◽  
Vol 71 (4) ◽  
pp. 744-752 ◽  
Author(s):  
Linda Weilgart ◽  
Hal Whitehead
Keyword(s):  
Social Cohesion ◽  
Temporal Pattern ◽  
Sequential Analysis ◽  
Sperm Whale ◽  
Galapagos Islands ◽  
Physeter Macrocephalus ◽  
Galápagos Islands ◽  
Sperm Whales ◽  
Insight Into

To gain insight into the function of sperm whale vocalizations known as codas (short, patterned series of clicks), sperm whales (Physeter macrocephalus) were tracked continuously for periods of days totalling months off the Galápagos Islands, Ecuador, and vocalizations were tape recorded systematically. In total, 1333 codas were classified according to their temporal pattern and the number of clicks they contained. Codas were found to be temporally very clustered, and could be categorized into 23 fairly discrete types. Sequential analysis of codas revealed that they overlapped one another according to type in a nonrandom way, and that type 5 tended to initiate coda exchanges. "Regular" coda types (with evenly spaced clicks) tended to occur with other regular coda types and "irregular" coda types (with one or two delayed final clicks) were heard with other irregular coda types. Codas may function principally as a means of communication, to maintain social cohesion within stable groups of females following periods of dispersion during foraging.

Foraging on squid: the sperm whale mid-range sonar

2007 ◽  
Vol 87 (1) ◽  
pp. 59-67 ◽  
Author(s):  
M. André ◽  
T. Johansson ◽  
E. Delory ◽  
M. van der Schaar
Keyword(s):  
Stomach Contents ◽  
Sperm Whale ◽  
Target Strength ◽  
Directional Hearing ◽  
Experimental Measurements ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Long Time ◽  
Minimum Requirements ◽  
The Subject

The sonar capabilities of the sperm whale, Physeter macrocephalus, have been the subject of speculation for a long time. While the usual clicks of this species are considered to support mid-range echolocation, no physical characteristics of the signal have clearly confirmed this assumption nor have they explained how sperm whales forage on squid. The recent data on sperm whale on-axis recordings have allowed us to simulate the propagation of a 15 kHz pulse as well as its received echoes from different targets, taking into account the reflections from the bottom and the sea surface. The analysis was performed in a controlled environment where the oceanographic parameters and the acoustic background could be modified. We also conducted experimental measurements of cephalopod target strength (TS) (Loligo vulgaris and Sepia officinalis) to further investigate and confirm the TS predictions from the geometric scattering equations. Based on the results of the computer simulations and the TS experimental measurements (TS squid=−36.3±2.5 dB), we were able to determine the minimum requirements for sperm whale sonar, i.e. range and directional hearing, to locate a single 24.5 cm long squid, considered to be (from stomach contents) the major size component of the sperm whale diet. Here, we present the development of the analysis which confirms that sperm whale usual clicks are appropriate to serve a mid-range sonar function, allowing this species to forage on individual organisms with low sound-reflectivity at ranges of several hundreds of metres.

SST fronts and the summer sperm whale distribution in the north-west Mediterranean Sea

2007 ◽  
Vol 87 (1) ◽  
pp. 187-193 ◽  
Author(s):  
Alexandre Gannier ◽  
Emilie Praca
Keyword(s):  
Mediterranean Sea ◽  
Feeding Strategy ◽  
Sperm Whale ◽  
Western Mediterranean ◽  
Relative Distribution ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
The North ◽  
North Western ◽  
Sst Fronts

The relative distribution of sperm whales (Physeter macrocephalus) and sea surface temperature (SST) fronts have been studied in summer in the north-western Mediterranean Sea. We used passive acoustic data (778 samples) obtained offshore during dedicated surveys between 1999 and 2004 and Pathfinder/Modis remote sensing data to compute front maps and to calculate mean distances from sperm whale detections (N=132) to SST-fronts. Mean distances from sperm whale acoustic detections to SST-fronts were significantly lower (10.4 km) than from other acoustic samples to those fronts (17.0 km). The same result was obtained when calculating distances from sperm whales to the North Balearic Front surface signature. If sperm whales are commonly observed along the continental slope, we showed that offshore individuals were located close to SST-fronts. This bimodal distribution in the north-western Mediterranean is linked to sperm whale feeding strategy, demonstrating ecological opportunistic behaviour in this high level predator.

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