Humans are not the only species on the planet to live in democracies. Many other animals, birds and insects make decisions by consensus and possibly better exemplify democracy. Abraham Lincoln famously said that democracy is, "government of the people, by the people and for the people," but the word "people" in that declaration easily could be replaced with other organisms, such as cockroaches.

Cockroaches govern themselves in a very simple democracy where each insect has equal standing and group consultations precede decisions that affect the entire group, according to a study published in the Proceedings of the National Academy of Sciences.

Cockroaches are silent, save perhaps for the sound of them scurrying on a kitchen counter top, but co-author Jose Halloy of the University of Paris Diderot told Discovery News that these resilient insects "use chemical and tactile communication with each other. They can also use vision."

Stickleback fish choose their leaders by consensus, with physical prowess swaying individual choices.

"It turned out that stickleback fish preferred to follow larger over smaller leaders," said Ashley Ward, an associate professor in the University of Sydney School of Biological Sciences, who investigated the fish. "Not only that, but they also preferred fat over thin, healthy over ill, and so on. The part that really caught our eye was that these preferences grew as the group size increased, through some kind of positive social feedback mechanism."

David Sumpter of Uppsala University added, "Their consensus arises through a simple rule. Some fish spot the best choice early on, although others may make a mistake and go the wrong way. The remaining fish assess how many have gone in particular directions. If the number going in one direction outweighs those going the other way, then the undecided fish follow in the direction of the majority."

Buffaloes "vote," according to Herbert Prins of Wageningen University.

Prins found that one or more buffaloes may gaze in a particular direction, with others following suit, or not. If the majority looks in a certain direction, he determined that they get up and move to the location. The visual votes therefore "reflect a measure of consensus."

Red deer don't just look to vote. They stand. If half or more of a herd stands, the entire group moves.

Tonkean macaques, like humans and most other primates, observe social hierarchies. Any member, however, may initiate group decisions among these macaques regardless of sex, age or status.

Humans, in contrast, tend to put more emphasis on these factors. U.S. presidents, for example, all have been men aged 42 years of age or older. (The 42-year-old was Theodore Roosevelt.)

Queen bees may be more like presidents than previously thought, since worker bees appear to influence the choice of queen. In an Insectes Sociaux journal paper, Stan Schneider of the University of North Carolina wrote, "How workers interact with the developing queens could influence who becomes the new queen."

Through swarming and other complex interactions, bees also make decisions on where to forage and settle.

Alpha males are at the top of chimpanzee social hierarchies, but they cannot hold their position without the support of females and other community members.

Hogan Sherrow of Ohio University spent eight years studying the Ngogo community of chimpanzees in Kibale National Park, western Uganda. In a Folia Primatologica study, he found that the biggest and oldest males tended to rise to alpha status, but not without forming key alliances in the community.

Mating, wooing females and impressing other chimps appear to constitute the "campaign" for the top spot among these primates.

Bechstein's bats "make group decisions about communal roosts," according to Peter Kappeler, author of the book "Animal Behaviour: Evolution and Mechanisms."

Individual bats can choose whether or not to follow group decisions, with dissenters forming subgroups. They later merge again, however, often achieving consensus.

Pigeons appear to compromise when making important decisions.

Kappeler writes that single pigeons, for example, may follow their own travel route to a location, but when paired with another pigeon with its own set travel path, the two will come to a compromise and travel together. The new route combines the best of both pigeons' knowledge of the journey.

While most mammals, including humans, live in areas with defended boundaries, a population of bottlenose dolphins in Shark Bay, Australia go against that norm. They live in an "open society," according to a study published in the Proceedings of the Royal Society B.

Co-author Richard Connor explained to Discovery News that "an open society is one without such defended boundaries."

He added, "We have seen precious little aggression between females. It does occur and is probably less frequent and more subtle." As for the male dolphins, even though "they are capable of serious aggression," he said, "they don't squabble constantly."