scholarly journals Population genetics and social organization of the sperm whale (Physeter macrocephalus) in the Azores inferred by microsatellite analyses

2009 ◽  
Vol 87 (9) ◽  
pp. 802-813 ◽  
Author(s):  
A. M. Pinela ◽  
S. Quérouil ◽  
S. Magalhães ◽  
M. A. Silva ◽  
R. Prieto ◽  
...  

In the northeast Atlantic Ocean, the archipelago of the Azores is frequented by female–offspring groups of sperm whales ( Physeter macrocephalus L., 1758), as well as large males. The Azores apparently constitute both a feeding ground and a reproduction site. Little is known about the population and group structure of sperm whales in the area. We analysed 151 sloughed skin and biopsy samples collected from 2002 to 2004. Molecular analyses involved genetic tagging using 11 microsatellite loci and molecular sexing. Our objectives were to determine the population genetic structure, compare relatedness within and between social groups, infer kinship, and estimate the age of males at dispersal. Results suggest that individuals visiting the archipelago of the Azores belong to a single population. High genetic diversity and absence of inbreeding suggest that the population is recovering from whaling. Individuals sampled in close association are highly related, as well as those observed in the same area on the same day, suggesting that secondary social groups (i.e., the union of primary social units) are largely but not exclusively composed of relatives. Probable mother–offspring and full-sibling pairs were identified. Age of males at dispersal was estimated at 16.6 years, which was well above previous estimates for this species.

1994 ◽  
Vol 72 (5) ◽  
pp. 873-877 ◽  
Author(s):  
Kenny R. Richard ◽  
Steven W. McCarrey ◽  
Jonathan M. Wright

We sequenced a 152 base pair fragment of the sperm whale (Physeter macrocephalus) SRY gene in order to obtain species-specific primers for determination of sex by the polymerase chain reaction (PCR). Sequence identity between the sperm whale SRY fragment and the homologous motif in a variety of other mammals was high, though generally higher with ungulates (~88%) than with the human (85%), rabbit (80%), mouse (75%), or marsupial mouse (66%). When primers based on the sperm whale sequence were employed for PCR, a single product was amplified from male sperm whale DNA, whereas no product was amplified from female DNA. This SRY fragment was also amplified from other cetacean male DNA, but not from human DNA. Thus, under appropriate PCR conditions, the use of the cetacean-specific primers in an assay to determine sex eliminates the possibility of false results owing to contamination by human DNA. To confirm the results of the SRY analysis we sexed the same individual sperm whales by restriction analysis of PCR-amplified fragments from the ZFY and ZFX genes, using universal primers and methods previously reported to work for other cetacean species.


PeerJ ◽  
2016 ◽  
Vol 4 ◽  
pp. e1895 ◽  
Author(s):  
Olga Panagiotopoulou ◽  
Panagiotis Spyridis ◽  
Hyab Mehari Abraha ◽  
David R. Carrier ◽  
Todd C. Pataky

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.


2016 ◽  
Vol 3 (6) ◽  
pp. 160061 ◽  
Author(s):  
Shane Gero ◽  
Anne Bøttcher ◽  
Hal Whitehead ◽  
Peter Teglberg Madsen

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.


2013 ◽  
Vol 280 (1763) ◽  
pp. 20131113 ◽  
Author(s):  
Shane Gero ◽  
Jonathan Gordon ◽  
Hal Whitehead

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.


2021 ◽  
Author(s):  
Justine Girardet ◽  
Francois Sarano ◽  
Gaëtan Richard ◽  
Paul Tixier ◽  
Christophe Guinet ◽  
...  

AbstractAdult male sperm whales (Physeter macrocephalus) are long distance runners of the marine realm, feeding in high latitudes and mating in tropical and subtropical waters where stable social groups of females and immatures live. Several areas of uncertainty still limit our understanding of their social and breeding behaviour, in particular concerning the potential existence of geographical and/or social fidelities.In this study, using underwater observation and sloughed-skin sampling, we looked for male social fidelity to a specific matrilineal sperm whale group near Mauritius. In addition, we captured a wider picture of kin relationships and genetic diversity of male sperm whales in the Indian Ocean thanks to biopsies of eight unique individuals taken in a feeding ground near the Kerguelen and Crozet Archipelagos (Southern Indian Ocean).Twenty-six adult male sperm whales, of which 13 were sampled, were identified when socializing with adult females and immatures off Mauritius. Long-term underwater observation recorded several noteworthy social interactions between adult males and adult females and/or immatures. We identified seven possible male recaptures over different years (three by direct observation, and four at the gametic level), which supports a certain level of male social fidelity. Several first- and second-degree kin relationships were highlighted between members of the social unit and adult males, confirming that some of the adult males observed in Mauritian waters are reproductive. Male social philopatry to their natal group can be excluded, as none of the males sampled shared the haplotype characteristic of the matrilineal social group. Mitochondrial DNA control region haplotype and nucleotide diversities calculated over the 21 total male sperm whales sampled were similar to values found by others in the Indian Ocean.Our study strongly supports the existence of some levels of male sperm whale social fidelity, not directed to their social group of birth, in the Indian Ocean. Males sampled in breeding and feeding grounds are linked by kin relationships. Our results support a model of male mediated gene flow occurring at the level of the whole Indian Ocean, likely interconnected with large-scale geographical fidelity to ocean basin, and a small-scale social fidelity to matrilineal social groups.


2020 ◽  
Vol 16 (2) ◽  
pp. 20190819 ◽  
Author(s):  
Ruairidh Macleod ◽  
Mikkel-Holger S. Sinding ◽  
Morten Tange Olsen ◽  
Matthew J. Collins ◽  
Steven J. Rowland

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.


Author(s):  
Stefan Huggenberger ◽  
Michel André ◽  
Helmut H. A. Oelschläger

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.


1993 ◽  
Vol 71 (4) ◽  
pp. 744-752 ◽  
Author(s):  
Linda Weilgart ◽  
Hal Whitehead

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.


Author(s):  
M. André ◽  
T. Johansson ◽  
E. Delory ◽  
M. van der Schaar

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.


Author(s):  
Alexandre Gannier ◽  
Emilie Praca

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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