April 17, 2012 15:55
Male dolphins in Shark Bay, Australia, known for its marine biologists complex social relationships. Their relationship with each other so unusual and resemble intricate mafia networks, rather than the vertical hierarchy of chimpanzees. About this in his article says a team of scientists who argue that such a social system is unique to mammals. What is interesting, the researchers suggest that such complex and often agreed with each other relationships may partly be due to one simple, but unexpected factors: low cruising speed of dolphins.
Mammals have developed a great variety of social structures. For example, chimpanzees live in what ethologists call half-groups — a community that includes individuals who are familiar with each other.
Community members generally unfriendly to the monkeys in the other groups; males practice what could be called the common defense, patrolling, security of its territory and the fight with the neighbors. Also within close groups of chimpanzees have the alliances between males.
At first glance, the Dolphins have something similar to the social system. Two or three adult males form a close alliance and combined to find females for mating. (Female dolphins rarely form strong relationships.) Other groups of males may attempt to kidnap a female, especially if she has heat. To win back the female, first-level unions are starting to work with other unions of first level, thus forming a large alliance of the second level. Some of these unions the second level can be up to 14 individuals and can be stored more than 15 years. In some cases, second-level unions can summon flocks of still other groups. Thus, the unions of the third order, as they are called scientists, leading to large-scale battles involving more than 20 bites and beating each other's heads and tails of dolphins, who are fighting for a lone female.
But is fighting dolphins similar to those that occur between the male chimpanzee? That is, the Dolphins are also fighting for territory? To find answers to these questions, the research team, led by Richard Connor, an expert on whales University of Massachusetts, for 6 years followed by twelve unions second order in Shark Bay (Bay in Western Australia area of 13 000 km2) during the breeding season, which peaks runs from July to November. Scientists observed the site of the Bay area of 600 km2, and marking of all individuals in each Union, exploring the area and the distance of their movements, their behavioral traits, whether male to female, or if there was a hassle, and what the group came to the aid of each other. The group then considered Connor's total home range for each union, and to map the degree of overlap between sites.
The research team found that in contrast to chimpanzees no group of males are not patrolled and protected by its large area habitat. Instead, the Dolphins were living in the community with a mosaic of multiple intersecting without visible boundaries of the habitat of males and females. "There is no common border patrolled by males or females," — says Connor, whose team published the information obtained in the journal "Proceedings of the Royal Society. Biology ". Instead, they are, according to him, they live in an open society in which the group while rallying and separated again. All this is Connor describes as "soap opera", where everyone is trying to find out what one has done more to based on this information to decide whether they will become friends or enemies.
"This is an unprecedented case, none of that observed in other communities of mammals," — says Srdjan Randich, a leading initiator of the study, a former student of Connor and a doctoral student in the University of Paris South-IX.
Despite the fact that bonobos, orangutans, gorillas and western have no such hostile relations with neighboring groups, such as chimpanzees, none of these species does not have the tolerance of dolphins or their ability to build alliances with individuals who do not belong to their immediate community. Among mammals, only elephants close enough, even though they live in the inherited through the maternal line groups, these animals maintain relationships outside of these groups, forming a large and multi-level community. But these large communities still largely built on kinship and are not as fickle as dolphins unions.
Due to the fact that female dolphins give birth to only one cub, which are separated by a few years, the males can not rely on the formation of alliances with a close kinship. Instead, males must learn to establish and maintain friendly relations. This requires high social skills and, according to Connor, probably contributed to the development of a large dolphin brain. But it is not only in the number of social relationships that need to support the Dolphins. In addition, should also take into account the uncertainty of third-level contacts. These are the guys with whom a rare vidites. How they were doing since you met them for the last time? Are they still on your side? "- Says Connor.
Among mammals, humans, elephants and dolphins are highly valued by scientists for their level of social cognition. Convergence, according to the team of Connor, may be due to the minimal energy costs over a normal movement. Dolphins, he adds, offering a model of how a small cruising speed may lead to social intelligence. Due to the fact that the population of dolphins in Shark Bay is very large and has overlapping areas habitat in one of the groups of dolphins did not take long to move at normal speed to the other, possibly rival group. In such situations the Dolphins have, according to scientists, to do two things, increase social cognition: Plant more friends and form a group alliances. Or how Connor adds, "If you are getting ready to face the enemy, it is best to be with friends and have a nearby who can come to the rescue."
"This is an extraordinary study shows that you can learn from a long-term study of undisturbed populations of dolphins," says Peter Korkeron researcher whales from the North East Research Center in ichthyology Vudhole, Massachusetts.
As for the suggestion that there may be a connection between the complexity of social communication and movement with the least amount of energy, just think about what happened when man invented the wheel, says Harvard University primatologist Richard Wray. "It was invented the wheel, and began to create the empire!".