In May 2015, nearly half of all the saigas, a critically endangered antelope that roams the steppe of Kazakhstan, died off. Exactly why is still a mystery.
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.
Mike Wilson, Jane Goodall Institute, Science
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.
The Dolphin Alliance Project
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."
It started in late May.
When geoecologist Steffen Zuther and his colleagues arrived in central Kazakhstan to monitor the calving of one herd of saigas, a critically endangered, steppe-dwelling antelope, veterinarians in the area had already reported dead animals on the ground.
"But since there happened to be die-offs of limited extent during the last years, at first we were not really alarmed," Zuther, the international coordinator of the Altyn Dala Conservation Initiative, told Live Science.
But within four days, the entire herd — 60,000 saiga — had died. As veterinarians and conservationists tried to stem the die-off, they also got word of similar population crashes in other herds across Kazakhstan. By early June, the mass dying was over. [See Images of the Saiga Mass Die-Off]
Now, the researchers have found clues as to how more than half of the country's herd, counted at 257,000 as of 2014, died so rapidly. Bacteria clearly played a role in the saigas' demise. But exactly how these normally harmless microbes could take such a toll is still a mystery, Zuther said.
"The extent of this die-off, and the speed it had, by spreading throughout the whole calving herd and killing all the animals, this has not been observed for any other species," Zuther said. "It's really unheard of."
Saigas play a critical role in the ecosystem of the arid grassland steppe, where the cold winters prevent fallen plant material from decomposing; the grazing of the dog-size, Gonzo-nosed antelopes helps to break down that organic matter, recycling nutrients in the ecosystem and preventing wildfires fueled by too much leaf litter on the ground. The animals also provide tasty meals for the predators of the steppe, Zuther said. [Images: Ancient Beasts of the Arctic]
"Where you find saiga, we recognize also that the other species are much more abundant," Zuther told Live Science.
Saigas, which are listed as critically endangered by the International Union for the Conservation of Nature, live in a few herds in Kazakhstan, one small herd in Russia and a herd in Mongolia. The herds congregate with other herds during the cold winters, as well as when they migrate to other parts of Kazakhstan, during the fall and spring. The herds split up to calve their young during the late spring and early summer. The die-off started during the calving period.
Die-offs of saigas, including one that felled 12,000 of the stately creatures last year, have occurred frequently in recent years. But the large expanse of the country affected by last year's die-off meant veterinarians couldn't get to the animals until long after their deaths. The delay hindered any determination of a cause of death, and researchers eventually speculated that an abundance of greenery caused digestion problems, which led to bacterial overgrowth in the animals' guts.
In May 2015, nearly half of all the saigas, a critically endangered antelope that roams the steppe of Kazakhstan, died off. Exactly why is still a mystery.Albert Salemgareyev
This time, field workers were already on the ground, so they were able to take detailed samples of the saigas' environment — the rocks the animals walked on and the soil they crossed — as well as the water the animals drank and the vegetation they ate in the months and weeks leading up to the die-off. The scientists also took samples of the ticks and other insects that feed on saiga, hoping to find some triggering cause.
The researchers additionally conducted high-quality necropsies of the animals, and even observed the behavior of some of the animals as they died. The females, which cluster together to calve their young, were hit the hardest. They died first, followed by their calves, which were still too young to eat any vegetation. That sequence suggested that whatever was killing off the animals was being transmitted through the mothers' milk, Zuther said.
Tissue samples revealed that toxins, produced by Pasteurella and possibly Clostridia bacteria, caused extensive bleeding in most of the animals' organs. But Pasteurella is found normally in the bodies of ruminants like the saigas, and it usually doesn't cause harm unless the animals have weakened immune systems.
Genetic analysis so far has only deepened the mystery, as the bacteria found were the garden-variety, disease-causing type.
"There is nothing so special about it. The question is why it developed so rapidly and spread to all the animals," Zuther said.
A similar mass die-off of 400,000 saigas occurred in 1988, and veterinarians reported similar symptoms. But because that die-off occurred during Soviet times, researchers simply listed Pasteurellosis, the disease caused by Pasteurella, as the cause and performed no other investigation, Zuther added.
So far, the only possible environmental cause was that there was a cold, hard winter followed by a wet spring, with lots of lush vegetation and standing water on the ground that could enable bacteria to spread more easily, Zuther said. That by itself doesn't seem so unusual, though, he said.
Another possibility is that such flash crashes are inevitable responses to some natural variations in the environment, he said. Zuther said he and his colleagues plan to continue their search for a cause of the die-off.
More frmo LiveScience:
In Photos: Google Earth Reveals Sprawling Geoglyphs in Kazakhstan
The Elusive Saola – Earth's Rarest Antelope | Unique Video
6 Extinct Animals That Could Be Brought Back to Life