Shark Dominance Hierarchies

Cross references:   Dominance Hierarchies in General   
 
Sharks: Solitary or Group Animals? (Goog) 
Very long article available online for free.   
    "Even though there is abundant evidence indicating that there is hardly a distinct social system within even socially segregated sharks, such as the Sychliorhinus canicula, the catshark, dominance hierarchy has been found to exist within Sphyrna tiburo, the bonnethead shark (Myrberg & Gruber, 1974).
    Myrberg and Gruber found that within a group of 10 individuals, there is a distinct, size-dependent linear dominance hierarchy determined by size more than anything else. Similar to how a dog rolls over to show its belly to a higher ranked individual, the sharks act submissively before a higher ranked individual. When the courses of two sharks intersect, the lesser-ranked individual will abruptly change course to avoid the more dominant shark. ... Myrberg and Gruber attribute this behavior to fear. They reason that the violence exhibited by male bonnetheads during mating assert their dominance, along with fear, in the group." 


Bimini Biological Field Station - shark research (Goog) 
Short article available online for free.   
    "
The second phase dealt with dominance in the group based on a form of avoidance behaviour called a Give-way. Using this behaviour it was found that there was perfect linearity in the hierarchy and was strongly correlated to size as the largest shark was most dominant and smallest shark was totally subordinate.

    "
During feeding sessions dominance also played a role in the proportion of meal obtained. The largest shark obtained on average the largest meal and the smallest shark on average obtained the smallest proportion of the meal.



Dive Into Your Imagination ... Submersible trip (Goog) 
Short article online. 
    "
The white sharks form temporary social structures whenever two or more individuals come together, such as around dead seals. In these situations, the white sharks form a dominance hierarchy, based largely on size and possibly temperament.



Biotelemetry Laboratory - White Sharks (Goog) 
Short, full length article available online for free. 
    "
Temporary social structures are formed with a dominance hierarchy based on size during predation events; similarly sized sharks can dissuade the competitor from eating its prey through displays (exaggerated swimming style) before a direct attack.
"   
 

Surrounded by blacktip sharks (Goog) 
Cool video.  Check it out. 
    "...
as long as the dominance hierarchy between them and humans is maintained, they make entertaining swimming companions.

 
 

The Behavior of the Bonnethead Shark, Sphyrna tiburo
Only first page available online. 
I was not able to copy-and-paste any of the text, but here is a transcription of the most important part. 
    "... a clear but subtle social organization, based on a straight-line, size-dependent, dominance hierarchy was found.  ... all individuals tended to shy away from larger males" 


Putative Male – Male Agonistic Behaviour in Free-Living Zebra Sharks (Goog) 
Full length PDF available online for free. 
    "Elasmobranchs do exhibit dominance hierarchies within both wild and captive reproductively active groups [7, 13-14], but direct observations of  agonistic interactions and evidence of how they maintain dominance hierarchies are still very limited."   
    "Action patterns performed in agonistic contexts are typically also used in other contexts, such as predatory behaviour, anti-predatory behaviour, and mating [10, 15]. For example, elasmobranch fishes exhibit a series of complex courtship and mating behaviours in which males inflict bite  wounds to the body of female mates [7, 16-17]. While bite wounds occur primarily on females, males are also the target of intrasexual biting [18] and such bite marks are usually attributed to aggressive interactions between consexuals for access to females. In both male and female elasmobranchs, not all bite marks result from reproductive activities, but possibly result from agonistic interactions [19]." 
    "The most cogent explanation for this encounter is as an agonistic interaction expressing or establishing a dominance hierarchy between these two male sharks. This hypothesis is the most cited ‘explanation’ for why animals engage in same-sex interactions which may or may not have a sexual motivation (review in [22-23]) and holds that mounting is a display of dominance, while being mounted is a display of submission. Dominant individuals mount subordinates to reaffirm their position in the dominance hierarchy. For example, in a study on nurse sharks, more successful copulations were obtained by several larger males, which were identified as dominant, than by smaller males [7]." 
    "Work with Atlantic stingrays [18] revealed fresh bite wounds on adults of both sexes during the full duration of the mating season and suggested that bite wounds on males may result from premating courtship attacks by males because females cannot be visually discriminated by the reproductively active males. It is unknown whether the described interaction occurred during a mating period." 
My comments
1.  I've always been confused by the term "
agonistic".  I've given a Wikipedia link for the term below the list of references in comment 2. 
2.  Here are the references given in the text: 

ref 7 
A review of elasmobranch reproductive behavior with a case study on the nurse shark (Goog) 
Only abstract available online. 
   "
Observations show ... three males dominant. Individual adult females visit the study area to mate in alternate years. ... Future research on reproductive behavior of elasmobranchs should address questions on male access to females, sexual selection and dominance hierarchies.

My comment
Dominance hierarchies not observed in this study. 

ref 13 
Already have, above. 

ref 14 
Pre-copulatory behavior of captive sandtiger sharks (Goog) 
Only abstract available online.   
    "
Dominance displays occurred between both mature and immature males in addition to aggression towards other objects, e.g. small carcharbinid sharks.

My comment
I glanced at the titles of the other references given in the excerpt, above, and it didn't look like any of them discussed dominance hierarchies. 

Agonistic behaviour (Wiki) 
    "In ethology, agonistic behaviour is any social behaviour related to fighting, such as aggressive or submissive behaviours. It explicitly includes behaviours such as subordinance, retreat and conciliation which are functionally and physiologically interrelated with aggressive behaviour, yet fall outside the narrow definition of "aggressive behaviour".


Schooling in Sphyrna lewini, a Species with Low Risk of Predation: a Non-egalitarian State (Goog) 
Only abstract available online. 
    "
The scalloped hammerhead, Sphyrna lewini, forms schools as highly polarized as those of the obligate schoolers... Furthermore, aggression is very common in schools of hammerheads; most individuals are females which compete for a position at the center of the school. Larger females perform two approach-type behaviors, Hit and Cork-screw, within the schools and force smaller sharks to the edge ...
"   


Great white shark:
I found this page by accident & will come back to it. 
It was on the first page of a Google search for "lungfish dominance hierarchy". 
Specific text via: Find "dominance" 

   "
This shark's behavior and social structure is not well understood. In South Africa, white sharks have a dominance hierarchy depending on size, sex and squatter's rights: Females dominate males, larger sharks dominate smaller sharks, and residents dominate newcomers. When hunting, great whites tend to separate and resolve conflicts with rituals and displays. White sharks rarely resort to combat although some individuals have been found with bite marks that match those of other white sharks.
"  


Great White Shark - COMET Corporation (Goog) 
Long article available online for free.  No references and not much about dominance hierarchies, but interesting. 
    "
Great white sharks, like all other sharks, have an extra sense given by the Ampullae of Lorenzini, which enables them to detect the electromagnetic field emitted by the movement of living animals. Every time a living creature moves it generates an electrical field and great whites are so sensitive they can detect half a billionth of a volt. Even heart beats emit a very faint electrical pulse. If close enough the shark can detect even that faint electrical pulse.
"     


Approaches to the Study of the Behavior of Sharks (Goog) 
Only abstract available online.   
Nothing quotable in the abstract. 

 
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