scholarly journals Vocal repertoires and insights into social structure of sperm whales ( Physeter macrocephalus ) in Mauritius, southwestern Indian Ocean

2020 ◽  
Vol 36 (2) ◽  
pp. 638-657
Author(s):  
Léonie A. E. Huijser ◽  
Vanessa Estrade ◽  
Imogen Webster ◽  
Laurent Mouysset ◽  
Adèle Cadinouche ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Social Structure ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Southwestern Indian Ocean

scholarly journals Social structure and residency in aggregations of male sperm whales

2002 ◽  
Vol 80 (7) ◽  
pp. 1189-1196 ◽  
Author(s):  
Erland Lettevall ◽  
Christoph Richter ◽  
Nathalie Jaquet ◽  
Elizabeth Slooten ◽  
Steve Dawson ◽  
...  
Keyword(s):  
Social Structure ◽  
Social Structures ◽  
Spatial Proximity ◽  
Residence Times ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Apparent Lack ◽  
Male Sperm ◽  
Close Spatial Proximity

Sperm whales (Physeter macrocephalus) are sexually dimorphic in several respects, including size, latitudinal distribution, and social structure. Females are known to have complex social structures, including long-term bonds, but the social structures of sexually mature or maturing males have received much less attention. Using data from aggregations of males off Norway, Nova Scotia, New Zealand, and the Galápagos Islands, we examined aggregation size, residence times within aggregations, clustering at the surface, and long-term bonds. Results were generally consistent among study areas. The aggregations found in each area contained around 10–30 males at any time, and were usually a few tens of kilometres across. Mean residence times within aggregations ranged from a few days to a few weeks. Close clustering at the surface was rare, but present at each site. There was no evidence for preferred companionship between individuals at any temporal scale in any of the study areas. The rarity of clustering and the apparent lack of long-term relationships amongst male sperm whales contrast strongly with results of studies on females, suggesting that both close spatial proximity at the surface and permanent bonds between individuals may be a consequence of the need for care of the young.

Social structure and mating system of sperm whales off northern Chile

2004 ◽  
Vol 82 (8) ◽  
pp. 1360-1369 ◽  
Author(s):  
Amanda K Coakes ◽  
Hal Whitehead
Keyword(s):  
Social Structure ◽  
Mating System ◽  
Relative Abundance ◽  
Northern Chile ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
The Social ◽  
Mean Size ◽  
Males And Females ◽  
The Mean

We studied the social structure and mating system of sperm whales (Physeter macrocephalus L., 1758) off northern Chile over 10 months in 2000, photographically identifying 898 individuals. The mean size of encountered groups of females with immatures was about 23 animals, while the estimated mean size of units (sets of females and immatures with permanent relationships) was 11 animals. About 4% of the population consisted of large mature males, although this varied seasonally. Groups of females and immatures, as well as large males, spent only a matter of days within the study area at a time. There was no evidence for preferred ranges for the males, for males consistently accompanying particular groups, or for males forming coalitions. Males roved between the groups of females and immatures. Both mature males and females or immatures appeared to take the initiative in maintaining or breaking close associations. These results are similar to those from studies off the Galápagos Islands, even though the habitat, nonsocial behaviour, and relative abundance of mature males were quite different in the two areas.

Temporal and geographic variation in the social structure of female sperm whales

1992 ◽  
Vol 70 (11) ◽  
pp. 2145-2149 ◽  
Author(s):  
Hal Whitehead ◽  
Benjamin Kahn
Keyword(s):  
Social Structure ◽  
Galapagos Islands ◽  
General Area ◽  
Physeter Macrocephalus ◽  
Galápagos Islands ◽  
Sperm Whales ◽  
The Social ◽  
Seychelles Islands ◽  
Mean Size ◽  
Geographic Differences

The social structure of female sperm whales (Physeter macrocephalus) was examined from data collected during studies of identified individuals off the Galápagos Islands in 1985, 1987, and 1989, off the Seychelles Islands in 1990, and off mainland Ecuador in 1991. Three levels of social organization were examined in the Galápagos Islands studies. "Units," permanent associations between individuals, showed no significant deviation from a mean size of 13 individuals. "Groups," temporary associations between units lasting a few days, had a mean size of 24 individuals. Group size was lower in 1987 (an "El Niño" year) than in 1985 or 1989, but this difference was not statistically significant. "Aggregations" of groups in the same general area lasting periods of hours were significantly larger in 1985 (mean of 77 individuals) than in 1987 (mean of 47 individuals). There are significant differences between areas in aggregation sizes but not in group sizes. Groups appear to aggregate frequently off the Galápagos Islands, occasionally off mainland Ecuador, and very rarely off the Seychelles Islands. These temporal and geographic differences in sizes of groups and aggregations in sperm whales are probably caused by variations in the distribution and abundance of their food, but responses to recent exploitation may also be a factor.

Isotopic niches of the blue shark Prionace glauca and the silky shark Carcharhinus falciformis in the southwestern Indian Ocean

2012 ◽  
Vol 17 (1) ◽  
pp. 83-92 ◽  
Author(s):  
N Rabehagasoa ◽  
A Lorrain ◽  
P Bach ◽  
M Potier ◽  
S Jaquemet ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Silky Shark ◽  
Carcharhinus Falciformis ◽  
Southwestern Indian Ocean

scholarly journals Severity Scoring of Behavioral Responses of Sperm Whales (Physeter macrocephalus) to Novel Continuous versus Conventional Pulsed Active Sonar

2021 ◽  
Vol 9 (4) ◽  
pp. 444
Author(s):  
Charlotte Curé ◽  
Saana Isojunno ◽  
Marije L. Siemensma ◽  
Paul J. Wensveen ◽  
Célia Buisson ◽  
...  
Keyword(s):  
Behavioral Responses ◽  
Physeter Macrocephalus ◽  
Vital Rates ◽  
Sperm Whales ◽  
Experimental Conditions ◽  
Active Sonar ◽  
Lower Amplitude ◽  
Pilot Whales ◽  
New Generation ◽  
Free Ranging

Controlled exposure experiments (CEEs) have demonstrated that naval pulsed active sonar (PAS) can induce costly behavioral responses in cetaceans similar to antipredator responses. New generation continuous active sonars (CAS) emit lower amplitude levels but more continuous signals. We conducted CEEs with PAS, CAS and no-sonar control on free-ranging sperm whales in Norway. Two panels blind to experimental conditions concurrently inspected acoustic-and-movement-tag data and visual observations of tagged whales and used an established severity scale (0–9) to assign scores to putative responses. Only half of the exposures elicited a response, indicating overall low responsiveness in sperm whales. Responding whales (10 of 12) showed more, and more severe responses to sonar compared to no-sonar. Moreover, the probability of response increased when whales were previously exposed to presence of predatory and/or competing killer or long-finned pilot whales. Various behavioral change types occurred over a broad range of severities (1–6) during CAS and PAS. When combining all behavioral types, the proportion of responses to CAS was significantly higher than no-sonar but not different from PAS. Responses potentially impacting vital rates i.e., with severity ≥4, were initiated at received cumulative sound exposure levels (dB re 1 μPa2 s) of 137–177 during CAS and 143–181 during PAS.

Behaviour and Vocalizations of Two Single Sperm Whales, Physeter macrocephalus, Off Nova Scotia

1988 ◽  
Vol 45 (10) ◽  
pp. 1736-1743 ◽  
Author(s):  
Julia Mullins ◽  
Hal Whitehead ◽  
Linda S. Weilgart
Keyword(s):  
Nova Scotia ◽  
Sound Production ◽  
Ocean Floor ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Scotian Shelf ◽  
Male Sperm

During June 1986, two male sperm whales, Physeter macrocephalus, on the Scotian Shelf were tracked by listening for their clicks with a directional hydrophone for periods of 12.5 and 7 h, respectively. Each whale travelled along the edge of the shelf at about 2 kn (3.6 km/h), and one whale, on two occasions at least, dived to the ocean floor. After about 30 min underwater, the whales spent approximately 9 min at the surface breathing. When the whales were visible at the surface, they were silent, except on one occasion when "slow clicking" (mean interclick interval of 4.6 s) was heard from Whale 2. While underwater, most of the sound production consisted of "usual clicks" (mean interclick interval 0.96 and 0.69 s for the two whales) interrupted by frequent short silences (mean durations 21.06 and 27.82 s) and occasional "creaks" (with interclick intervals less than 0.2 s) and "slow clicks." No "codas" (stereotyped patterns of clicks) were heard from these two single whales. These results are consistent with the hypotheses that "usual clicks" and "creaks" are used for echolocation and "codas" for communication.

Variations in the feeding success and behaviour of Galápagos sperm whales (Physeter macrocephalus) as they relate to oceanographie conditions

1993 ◽  
Vol 71 (10) ◽  
pp. 1991-1996 ◽  
Author(s):  
Sean C. Smith ◽  
Hal Whitehead
Keyword(s):  
Surface Temperature ◽  
Significant Variation ◽  
Foraging Behaviour ◽  
Geographic Area ◽  
Sea Surface ◽  
Physeter Macrocephalus ◽  
Sperm Whales ◽  
Feeding Success ◽  
Galapagos Archipelago ◽  
Oceanographic Conditions

The feeding success of sperm whales off the Galápagos Islands, Ecuador, was examined over 5 study years; 1985, 1987, 1988, 1989, and 1991. A total of 160 days were spent following sperm whales at sea. The defaecation rates of sperm whales were used as an indication of feeding success. The recorded acoustic click rates of sperm whales were used as an indication of aggregative and foraging behaviour. Significant variation in feeding success occurred temporally over periods of days, months, and years. Feeding success also varied spatially with geographic area. Feeding success was inversely related to sea surface temperature (SST). The foraging and associative behaviour of sperm whales also varied with feeding success, SST, and by year. Variations in the feeding success and behaviour of Galápagos sperm whales can likely be attributed to changing oceanographic conditions in the waters surrounding the Galápagos archipelago.

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