Dominance is a reoccurring theme in nature and the reason is quite simple. To make optimum use of reproductive potential all females of a given species need to participate in the process. This ensures the maximum number of progeny per breeding season.
Male participation is another matter. Under ideal conditions a single male of a given species would be best suited to fulfill all the duties of a progenitor. One male has all the attributes necessary to sire offspring with the best survival potential. OK maybe two or three or even four males are the best but if the parameters are fine tuned enough either the three or even four one will be marginally better. So, under ideal conditions it is one male and all the females for the best selective results and the hell with the rest of the males.
It does not work that way. It would be impossible for a single male elephant to service all the hot to trot female elephants in Africa. Not only would the beast be worn to a frazzle but his equipment would also be, let us say, over extended. This same situation would be true for most organizations, buffalo in North America, llamas in South America, lions in Africa, or even kangaroo in Australia. All of these species would benefit if a single male sired all of the offspring. But in all of these cases as well as in all other instances this is not possible.
But organizations that aspire to this ideal have better survival potential. In those cases where males contend with each other to determine dominance rank is established and the dominant males service the females to which they have exclusive entree. This is as close as natural selection can come to the ideal of one male and all the females. This is why dominance occurs in most social species.
Dominance predisposition is deeply woven into the genetic fabric of all animals. Reptiles, fish, mammals, birds, and even insects all demonstrate dominance predisposition. Anthia serranocirrhitus is a species of small fish that carries dominance to its logical extreme. All Anthia in a school are born female. But male input is required to fertilize the eggs and the story of the missing male is one of nature's best.
Anthia schools consist of fish of various ages and the established dominance system is based exclusively on age, and hence, size. The whole school is dominated by one – male. But where did the male come from if all of the Anthia were born female? Well, at one time that he was a she contributing like all other shes to the production of eggs. When the dominant male dies, the next Anthia in line, a female, undergoes a physical change from female to male. Sexual organs that are female whither and in their place male sexual organs develop. So after several years of contributing only a number of eggs to the school gene pool she becomes a he with the responsibility of fertilizing all of the eggs. And that passing on her / his dominance predisposition to succeeding generations. All of this is accomplished through dominance in Anthia society.
Closer to home among primates, we also see dominance systems in place. Gorillas have gone the way of the harem, one silver backed male with several female companions. As male gorillas reach adulthood within the silver back's group he drives them out. They in turn lead a bachelor life until they mature to become silver backs in their own right at which time they will challenge the harem master for leadership of the troop.
Among chimps a different different hierarchy presents itself. Troops consist of mature as well as immature males and females. Both males and females establish dominance hierarchies. Males, many times, form alliances with other males each supporting the other when challenged. Single males have little or no chance of overriding such a coalition unless they too form mutual support relationships. Dominance is common in chimps, even bonobos, the sexiest of chimps establish dominance system both male and female lines. They do this because dominance has survival value.
More dominant members of a species have better prospects in everything. Dominant animals take food from less dominant animals. The best sleeping places, the best resting places, all go to the more dominant individuals. As a result, their lives are marginally easier. But the main benefit of being the dominant male animal in chimp society is that females are attracted to dominant males.
When a female chimp comes into heat, she will be served by all of the males in turn. But at that time when she is most likely to conceive she sometimes runs away with one of the more dominant males and the two will copulate numerous times to the exclusion of other males. As a result, because dominance behavior presents males with increased reproductive potential it is maintained within the chimp troop.
How common and intensive is dominance among male chimps? One set of observations done recently by primatologists leads to the conclusion that one third of all chimp males are killed by other chimp males. Dominance is an important part of evolution. It is an important behavior among chimps, both male and female.
Dominance also occurs in insects. In Southeast Asia lives a bug, but not just any bug. At five inches in length and three and a half ounces this is one big bug. It is called the Rhinoceros Beetle (chalcosoma atlas) and for very good reason. The head of this beetle is adorned with three large horns two on the upper part that are fixed and one on the lower part that is moveable. Between them, these horns act like pincers and are used by the males for jousting with other males. Dominance, as a method for determining survival and procreative potential is alive and well among the world's insects.
Rhinoceros Beetles live in rotting vegetation and logs in the jungles of Malaysia and Indonesia. Female rhinoceros beetles lay their eggs in rotting logs and the larvae feast on these fallen banquets. Males vie and joust with other males to occupy and defend the most desirable spots on the rotting logs. More dominant males occupy the best food sources and attract the most females. The result is beetle offspring with the male's predisposition to take and defend desirable food niches. Dominance survives because dominance works even amongst insects.
Dominance is common among birds, not just chickens but many many flocking birds. It has value, it sorts and separates, it keeps the species healthy and better able to cope with survival and reproductive problems. Stronger, tougher birds make better parents producing healthy chicks, which share among others passed on attributes a predisposition towards dominance.
On the plains of Africa there lives the largest land animal in the world. African elephant bulls can measure over 12 feet at the shoulder and weigh more than 10 tons. Both males and females establish dominance hierarchies. Although the female's ranks are looser than those of the males.
Elephant social life is built around the cows and calves. A herd consistants of females, calves, and adolescent offspring. When a bull calf reaches the first stages of maturity he is driven from the herd to live a life of near solitude. A bull is allowed to approach the females only when he is fully adult and has demonstrated a dominant position in the male hierarchy. Female elephants prefer to mate with dominant bulls because offspring of such bulls have a better chance of becoming dominant and passing on their genes. Such bull potential also has benefit from a fitness standpoint. These animals are stron
ger, healthier, and larger. All of this improvements the survival and procreative potential of a calf. And so a predisposition to dominance is maintained within the elephant society for the very simple reason that it has survival value.
We are social animals. We have dominance systems built into our social fabric. Every culture that has ever existed is a dominance system. Every culture that has ever been described says: If you do the following things you will be looked up to, expected, respected, and given status. If, however, you do not follow our laws and rules and customs and manners, we will look down upon you, criticize you, judge you unfavorably, and possibly kill you. Within the social group this is the common thread that ties every one together. Individuals know who is the leader and who are the followers. Things are done, actions are taken, in accordance with rank. Power – and responsibility goes with status, and esteem is stated to high ranking individuals. Each member especially the males devote a great deal of time and energy to improving status. At one time, this was accomplished mainly through strength. But now, it is accomplished as much through guile and intelligence as it is through strength. And increasingly the role becomes more and more complicated, more and more difficult to achieve. And yet, we aspire, we try, we scheme and plan, to achieve dominance within our social group.
Always it is dominance.