Individual Prey Specialization Drives PCBs in Icelandic Killer Whales

2021 ◽  
Vol 55 (8) ◽  
pp. 4923-4931
Author(s):  
Anaïs Remili ◽  
Robert J. Letcher ◽  
Filipa I.P. Samarra ◽  
Rune Dietz ◽  
Christian Sonne ◽  
...  
Keyword(s):  
Killer Whales ◽  
Prey Specialization ◽  
Individual Prey

scholarly journals Complex interactions between components of individual prey specialization affect mechanisms of niche variation in a grasshopper-hunting wasp

2011 ◽  
Vol 80 (6) ◽  
pp. 1123-1133 ◽  
Author(s):  
Davide Santoro ◽  
Carlo Polidori ◽  
Josep D. Asís ◽  
José Tormos
Keyword(s):  
Complex Interactions ◽  
Niche Variation ◽  
Prey Specialization ◽  
Individual Prey

Personality in captive killer whales (Orcinus orca): A rating approach based on the five-factor model.

2019 ◽  
Vol 133 (2) ◽  
pp. 252-261 ◽  
Author(s):  
Yulán Úbeda ◽  
Sara Ortín ◽  
Judy St. Leger ◽  
Miquel Llorente ◽  
Javier Almunia
Keyword(s):  
Factor Model ◽  
Five Factor Model ◽  
Orcinus Orca ◽  
Killer Whales

Depredation by Killer Whales (Orcinus orca) on a Blue Shark (Prionace glauca) in Northeastern Atlantic

2020 ◽  
Vol 46 (5) ◽  
pp. 478-482
Author(s):  
Gonzalo Mucientes ◽  
Adriana González-Pestana
Keyword(s):  
Orcinus Orca ◽  
Killer Whales ◽  
Blue Shark ◽  
Prionace Glauca ◽  
Northeastern Atlantic

Diet

2017 ◽  
Author(s):  
M.G.L. Mills ◽  
M.E.J. Mills
Keyword(s):  
Prey Species ◽  
Radio Tracking ◽  
Relative Occurrence ◽  
Important Prey ◽  
Individual Prey ◽  
Sibling Groups

Four methods were used to document the diet of cheetahs: incidental observations, radio tracking, tracking, spoor, and continuous follows. A combination of continuous follows and tracking spoor gave the best results. Steenbok were the most frequently killed species, but they did not dominate the diet in the same way as Thomson’s gazelle do in the Serengeti. Coalition males have a different diet profile from single males, single females, females with cubs, and sibling groups. For all but single males, the relative occurrence of prey species in the diet reflected its dietary importance in terms of kilograms of meat obtained. Gemsbok calves and adult ostrich were important prey for coalition males and springhares were important for single males. Three individual prey specializations for females were found; namely springbok specialists, steenbok/duiker specialists, and intermediates. Contrary to an earlier study, springbok were not found to be the most important prey species.

First record of Norwegian killer whales attacking and feeding on a harbour porpoise

2015 ◽  
Vol 8 ◽  
Author(s):  
A. Mel Cosentino
Keyword(s):  
North Atlantic ◽  
Marine Mammals ◽  
First Record ◽  
Harbour Porpoise ◽  
Sperm Whales ◽  
Killer Whales ◽  
Strait Of Gibraltar ◽  
Cetacean Species ◽  
The North ◽  
Northern Bottlenose Whales

Orcinus orcais a cosmopolitan species and the most widely distributed marine mammal. Its diet includes over 140 species of fish, cephalopods, sea birds and marine mammals. However, many populations are specialised on certain specific prey items. Three genetically distinct populations have been described in the North Atlantic. Population A (that includes the Icelandic and Norwegian sub-populations) is believed to be piscivorous, as is population C, which includes fish-eating killer whales from the Strait of Gibraltar. In contrast, population B feeds on both fish and marine mammals. Norwegian killer whales follow the Norwegian spring spawning herring stock. The only description in the literature of Norwegian killer whales feeding on another cetacean species is a predation event on northern bottlenose whales in 1968. Daily land-based surveys targeting sperm whales were conducted from the Andenes lighthouse using BigEyes®binoculars (25×, 80 mm). The location of animals at sea was approximated through the use of an internal reticule system and a graduated wheel. On 24 June 2012 at 3:12 am, an opportunistic sighting of 11 killer whales was made off Andenes harbour. The whales hunted and fed on a harbour porpoise. Despite these species having overlapping distributions in Norwegian waters, this is the first predatory event reported in the literature.

scholarly journals Survival of the fattest: linking body condition to prey availability and survivorship of killer whales

Ecosphere ◽  
2021 ◽  
Vol 12 (8) ◽  
Author(s):  
Joshua D. Stewart ◽  
John W. Durban ◽  
Holly Fearnbach ◽  
Lance G. Barrett‐Lennard ◽  
Paige K. Casler ◽  
...  
Keyword(s):  
Body Condition ◽  
Prey Availability ◽  
Killer Whales

scholarly journals Mixture models as a method for comparative sociality: social networks and demographic change in resident killer whales

2021 ◽  
Vol 75 (4) ◽  
Author(s):  
Samuel Ellis ◽  
Daniel W. Franks ◽  
Michael N. Weiss ◽  
Michael A. Cant ◽  
Paolo Domenici ◽  
...  
Keyword(s):  
Mixture Models ◽  
Demographic Change ◽  
Social Preferences ◽  
Social Bonds ◽  
Killer Whales ◽  
Animal Populations ◽  
Binomial Mixture ◽  
Opposite Sex ◽  
Social Associations ◽  
Social Association

Abstract In studies of social behaviour, social bonds are usually inferred from rates of interaction or association. This approach has revealed many important insights into the proximate formation and ultimate function of animal social structures. However, it remains challenging to compare social structure between systems or time-points because extrinsic factors, such as sampling methodology, can also influence the observed rate of association. As a consequence of these methodological challenges, it is difficult to analyse how patterns of social association change with demographic processes, such as the death of key social partners. Here we develop and illustrate the use of binomial mixture models to quantitatively compare patterns of social association between networks. We then use this method to investigate how patterns of social preferences in killer whales respond to demographic change. Resident killer whales are bisexually philopatric, and both sexes stay in close association with their mother in adulthood. We show that mothers and daughters show reduced social association after the birth of the daughter’s first offspring, but not after the birth of an offspring to the mother. We also show that whales whose mother is dead associate more with their opposite sex siblings and with their grandmother than whales whose mother is alive. Our work demonstrates the utility of using mixture models to compare social preferences between networks and between species. We also highlight other potential uses of this method such as to identify strong social bonds in animal populations. Significance statement Comparing patters of social associations between systems, or between the same systems at different times, is challenging due to the confounding effects of sampling and methodological differences. Here we present a method to allow social associations to be robustly classified and then compared between networks using binomial mixture models. We illustrate this method by showing how killer whales change their patterns of social association in response to the birth of calves and the death of their mother. We show that after the birth of her calf, females associate less with their mother. We also show that whales’ whose mother is dead associate more with their opposite sex siblings and grandmothers than whales’ whose mother is alive. This clearly demonstrates how this method can be used to examine fine scale temporal processes in animal social systems.

scholarly journals Family feud: permanent group splitting in a highly philopatric mammal, the killer whale (Orcinus orca)

2021 ◽  
Vol 75 (3) ◽  
Author(s):  
Eva H. Stredulinsky ◽  
Chris T. Darimont ◽  
Lance Barrett-Lennard ◽  
Graeme M. Ellis ◽  
John K. B. Ford
Keyword(s):  
Killer Whale ◽  
Group Structure ◽  
Group Living ◽  
Orcinus Orca ◽  
Learning Approaches ◽  
Killer Whales ◽  
Internal Factors ◽  
Individual Fitness ◽  
Leadership Experience

Abstract For animals that tend to remain with their natal group rather than individually disperse, group sizes may become too large to benefit individual fitness. In such cases, group splitting (or fission) allows philopatric animals to form more optimal group sizes without sacrificing all familiar social relationships. Although permanent group splitting is observed in many mammals, it occurs relatively infrequently. Here, we use combined generalized modeling and machine learning approaches to provide a comprehensive examination of group splitting in a population of killer whales (Orcinus orca) that occurred over three decades. Fission occurred both along and across maternal lines, where animals dispersed in parallel with their closest maternal kin. Group splitting was more common: (1) in larger natal groups, (2) when the common maternal ancestor was no longer alive, and (3) among groups with greater substructuring. The death of a matriarch did not appear to immediately trigger splitting. Our data suggest intragroup competition for food, leadership experience and kinship are important factors that influence group splitting in this population. Our approach provides a foundation for future studies to examine the dynamics and consequences of matrilineal fission in killer whales and other taxa. Significance statement Group living among mammals often involves long-term social affiliation, strengthened by kinship and cooperative behaviours. As such, changes in group membership may have significant consequences for individuals’ fitness and a population’s genetic structure. Permanent group splitting is a complex and relatively rare phenomenon that has yet to be examined in detail in killer whales. In the context of a growing population, in which offspring of both sexes remain with their mothers for life, we provide the first in-depth examination of group splitting in killer whales, where splitting occurs both along and across maternal lines. We also undertake the first comprehensive assessment of how killer whale intragroup cohesion is influenced by both external and internal factors, including group structure, population and group demography, and resource abundance.

scholarly journals Gut microbiome is affected by inter-sexual and inter-seasonal variation in diet for thick-billed murres (Uria lomvia)

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Esteban Góngora ◽  
Kyle H. Elliott ◽  
Lyle Whyte
Keyword(s):  
Gut Microbiome ◽  
Sulfur Isotopes ◽  
Trophic Position ◽  
Isotope Analysis ◽  
16S Rrna Gene Sequencing ◽  
Rrna Gene ◽  
Uria Lomvia ◽  
Fecal Microbiome ◽  
Prey Specialization ◽  
Rrna Gene Sequencing

AbstractThe role of the gut microbiome is increasingly being recognized by health scientists and veterinarians, yet its role in wild animals remains understudied. Variations in the gut microbiome could be the result of differential diets among individuals, such as variation between sexes, across seasons, or across reproductive stages. We evaluated the hypothesis that diet alters the avian gut microbiome using stable isotope analysis (SIA) and 16S rRNA gene sequencing. We present the first description of the thick-billed murre (Uria lomvia) fecal microbiome. The murre microbiome was dominated by bacteria from the genus Catellicoccus, ubiquitous in the guts of many seabirds. Microbiome variation was explained by murre diet in terms of proportion of littoral carbon, trophic position, and sulfur isotopes, especially for the classes Actinobacteria, Bacilli, Bacteroidia, Clostridia, Alphaproteobacteria, and Gammaproteobacteria. We also observed differences in the abundance of bacterial genera such as Catellicoccus and Cetobacterium between sexes and reproductive stages. These results are in accordance with behavioural observations of changes in diet between sexes and across the reproductive season. We concluded that the observed variation in the gut microbiome may be caused by individual prey specialization and may also be reinforced by sexual and reproductive stage differences in diet.

RESIGHTINGS AND BEHAVIOR OF FALSE KILLER WHALES ( PSEUDORCA CRASSZDENS ) IN COSTA RICA

1997 ◽  
Vol 13 (2) ◽  
pp. 307-314 ◽  
Author(s):  
ALEJANDRO ACEVEDO‐GUTIÉRREZ ◽  
BERNARD BRENNAN ◽  
PATRICIA RODRIGUEZ ◽  
MOLLY THOMAS
Keyword(s):  
Costa Rica ◽  
Killer Whales ◽  
And Behavior
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