List of dominance hierarchy species
[6][7] Common chimpanzees show deference to the alpha of the community by ritualized postures and gestures such as presenting their back, crouching, bowing, or bobbing.
Gaining dominance, that is becoming the alpha male, results in an "increased testicular volume, reddening of sexual skin on the face and genitalia, and heightened secretion of the sternal cutaneous gland".
Dominant male elephant seals arrive at potential breeding sites in spring, and fast to ensure that they can mate with as many females as possible.
This terminology was first used in 1947 by Rudolf Schenkel of the University of Basel, who based his findings on researching the behavior of captive gray wolves.
He later found additional evidence that the concept of an Alpha male may have been an interpretation of incomplete data and formally disavowed this terminology in 1999.
Later research on wild gray wolves revealed that the pack is usually a family consisting of a breeding pair and their offspring of the previous 1–3 years.
[24] Webster et al. observed that males defend sexually-receptive females, suggesting that Montezuma oropendolas have a female-defence mating system.
[27] Subordinate co-breeding males may have reproductive fitness benefits by assisting the alpha female with nest defense and prey provision.
[26] Aggressive behavior in cichlids is ritualized and consists of multiple displays used to seek confrontation while being involved in evaluation of competitors,[29] coinciding with temporal proximity to mating.
[30] In addition to color displays, cichlids employ their lateral lines to sense movements of water around their opponents to evaluate the competing male for physical traits/fitness.
[31] Male cichlids are very territorial due to the pressure of reproduction, and establish their territory and social status by physically driving out[32] challenging males (novel intruders)[33] through lateral displays (parallel orientation, uncovering gills),[34] biting, or mouth fights (head-on collisions of open mouths, measuring jaw sizes, and biting each other's jaws).
The cichlid social dichotomy is composed of a single dominant with multiple subordinates, where the physical aggression of males becomes a contest for resources[32] (mates, territory, food).
[35] The alpha male is more brightly colored, and at every low tide hour, changes from green to blue, and goes into a show of attacking and nipping all the other wrasses.
During breeding season and before high tide, the alpha male turns completely blue, gathers up every single female, and the spawning frenzy begins.
[36] In terms of social structure, Mozambique tilapias engage in a system known as lek-breeding, where males establish territories with dominance hierarchies while females travel between them.
[38] In experiments with captive tilapias, evidence demonstrates the formation of linear hierarchies where the alpha male participates in significantly more agonistic interactions.
However, contrary to popular belief, Mozambique tilapias display more agonistic interactions towards fish that are farther apart in the hierarchy scale than they do towards individuals closer in rank.
In this context, members of this social system tend to avoid confrontations with neighboring ranks in order to conserve resources rather than engage in an unclear and risky fight.
