The Great Apes: Intelligence, News, Videos and Articles

[Image and article from here.]

One of humankind's closest relatives, the bonobo, may be facing extinction.

Scientists working in the Democratic Republic of the Congo - the only country where bonobos live - have found evidence that they are being hunted for bushmeat in areas where they should be protected.

Numbers may be down to 20% of previous levels.

They look like a smaller, cuter version of the chimpanzee; and uniquely among animal species, they use casual sex to bond social groups.

Bonobos are as closely related to us as chimps are. But research from a coalition of conservation groups led by WWF suggests their numbers may be in sharp decline.

In areas of the Salonga National Park where previously bonobos had been abundant, scientists saw no live animals at all - they heard calls, they saw droppings and nests, but made no actual sightings.

Peter Stephenson, the co-ordinator of WWF's African Great Apes programme, said: "What was disturbing is first, that they were finding fewer bonobos than had previously been found in areas where we know bonobos to occur; and secondly, they found lots of traces of people being in the park and traces of active hunting.

"And basically as this is a national park, all of this hunting was illegal, and therefore poaching."

The root cause of the bonobo's plight is the DRC's history of conflict.

Protection work has been extremely difficult, there's been a demand for bushmeat, and armed gangs have moved into some areas of the Salonga Park.

Researchers say they encountered elephant poachers armed with semi-automatic weapons.

Salonga is the only area where bonobos are supposed to be protected in the only country in which they live - it is crucial to their survival.

WWF and its partners have launched a new initiative to track the remaining populations and prevent their extinction.

"It's been almost impossible for the Congolese Institute for Nature Conservation, which runs the national parks, to function properly in most of the protected areas in DRC during the war, " continued Peter Stephenson.

"Armed militias often use national parks as areas to hide out because of the dense forest; and that's been the case in Salonga too - armed militias have hidden out there - and for sure, with the easier availability of guns, it's been easier for people to hunt bonobos as well as other threatened species such as elephants.

"The problem with estimating the population of bonobos, like any other large mammals that live in dense rainforest, is it's not terribly easy to count them.

"And so over the last few decades, people's estimates of population have largely been based on counting animals in a small area, and then extrapolating up, based on the densities they find in the small areas, and trying to estimate how many there might be in the broader Congo Basin.

"So, the methods haven't up until now been incredibly accurate; but based on the efforts that have been made, we think there were between 10,000 and 50,000 bonobos in the Congo Basin."

[Image and article from here.]

In parts of the Republic of Congo in equatorial Africa, nearly all the gorillas are gone. Since 2001 gorilla and chimpanzee remains have showed up near and in the Lossi Sanctuary, close to the Gabon border. Just what was killing these great apes was unclear. Now researchers finger the Zaire strain of the Ebola virus as the culprit. "No doubt that's what killed them," says Peter Walsh, a primatologist at the Max Planck Institute for Evolutionary Anthropology. He and his team estimate that the virus has killed 5,500 gorillas in the northwestern part of the country.

Of four subtypes of the Ebola virus, Ebola Zaire is the nastiest, Walsh says. This virus has about an 80 percent mortality rate and infects primates, including humans. The disease begins with a headache and leads, in about a week, to hemorrhagic fever and organ failure.

Magdalena Bermejo, the lead researcher on this study from the University of Barcelona, had worked in the Lossi Sanctuary to habituate the gorillas to people. Then, in 2002, the researchers noticed that the gorillas were dying. Between October 2002 and January 2003, 91 percent of the 143 gorillas Bermejo worked with disappeared. Remains found in the area tested positive for Ebola Zaire. The next year, 95.8 percent of another group of gorillas Bermejo had worked with also died.

To estimate how many gorillas in the region perished, the researchers compared the difference in the number of gorilla nests found in an affected area with one that was unaffected. East of the Lossi Sanctuary, few gorillas had become ill. In the western part of the region, which included most of the sanctuary, researchers found just 4 percent as many gorilla nests than in the unaffected east. In their calculations, the researchers assumed, based on populations in the sanctuary, that the 2,700-square-kilometer western zone had a pre-Ebola gorilla density of 2.2 animals per square kilometer, or nearly 6,000 individuals, leading them to conclude in this week's Science that about 5,500 gorillas died of Ebola Zaire.

"Probably a lot more than 5,000 died," Walsh says, adding that they made a conservative estimate. Based on the number of nests, about 83 percent of chimpanzees died of Ebola, too, the researchers say.

It is possible that some deaths resulted from something other than Ebola Zaire, says Gary Nabel, a virologist at the National Institutes of Health who was not involved in the study. "It is always hard to be airtight, he says, noting that other viruses, including smallpox and Marburg, also lead to hemorrhagic fever and could be striking the great apes as well. In any case, the disease striking the gorillas fits the pattern of an epidemic, Nabel says. It is a warning shot over the bow in terms of threat to this species, and to us, too, he adds.

Gorillas and chimpanzees have some hope. Ebola is not popping up randomly, and scientists are developing vaccines. Walsh estimates, however, that it might take $5 million to $10 million to test and deliver the vaccine safely to the gorillas or chimpanzees--who are, he points out, our closest relatives.

[Article from here.]

In this book, Carel van Schaik, a highly regarded Dutch primatologist now at Duke University, concludes that "intelligence is ... socially constructed during development." This won't surprise you--until you realize that he is referring not to humans but to orangutans, the large red apes of south Asia. Van Schaik proposes that the discovery of orangutan culture can provide a resolution to a long-standing puzzle: Why are apes so smart? Perhaps the complexities of great ape social relationships selected for large brains. But orangutans challenge this "social intelligence" hypothesis: in the wild, they mostly travel about by themselves, yet they are at least as smart as chimpanzees.

Van Schaik thinks that social factors are indeed pivotal in explaining orangutan intelligence, but not in the way proposed by the social intelligence hypothesis. In a beautifully written, compelling narrative that reads like a detective story, he weaves together several threads of evidence to argue that orangutan intelligence is intimately related to technological innovations that are passed down through social learning.

Before hearing about the details of orangutan culture, we accompany van Schaik into the fetid, mosquito-ridden swamp forests of western Sumatra (succinctly described as human hell--but orangutan heaven). Through the large number of outstanding color photographs, we meet many of the 100 orangutans his team recognized individually. They are handsome creatures with long red hair, expressive faces and round eyes that gaze out of the photographs with keen awareness.

Orangutans do something clever that other great apes don't do: they use leaves to make rain hats and leakproof roofs over their sleeping nests. But until recently, there was scant evidence of other kinds of toolmaking. At van Schaik's site, tools were common, and he documents in detail how the orangutans fashion tools out of twigs. They use some tools to fish for ants or termites, while they skillfully manipulate others to get at scrumptious seeds protected by razor-sharp hairs. At first glance, these tools do not seem to reflect advanced cognitive skills, but on closer inspection van Schaik found that each tool is carefully crafted to match the precise needs of a given situation. And like chimpanzees, orangutans sometimes make tools for later use, an apparent example of conscious planning.

How do we know that such feats represent culture? The argument is complex, but in brief, orangutans' use of tools on the islands of Sumatra and Borneo varies geographically in ways that cannot be explained by ecological or genetic differences between populations. Instead these differences are best explained by variation in sociability, as well as by the locations of geographic barriers preventing cultural diffusion between populations.

In most places, intense feeding competition prevents orangutans from forming groups, and in these situations, tool use is rudimentary or absent. But swamp forests are highly productive, allowing van Schaik's orangutans to associate a lot. As a result, youngsters spend many hours closely watching tolerant elders make and use tools. After about seven years of learning and practice, they, too, become skillful tool users.

Because we already knew that material cultures vary among chimpanzee populations, why is the discovery of orangutan culture so important? Van Schaik provides three reasons: First, the existence of culture in orangutans can explain why they are so smart--something the social intelligence hypothesis cannot do. Second, orangutan ancestors split from the great ape lineage as long as 15 million years ago, leading van Schaik to argue that the common ancestor of all great apes (including humans) had culture at least that far back in time. If so, then the roots of human culture are much older than previously thought. Third, if the ancestor of all living great apes had the capacity for material culture, then the origins of culture must be sought in older (nonderived) traits that characterized these ancient apes. This brings us back to the question we began with: How did apes get to be so smart?

Van Schaik finds the answer in a surprising place: the tops of the trees. Because ancestral apes were both large-bodied and arboreal, they were much less vulnerable to predation than other mammals of their time. According to life history theory, reduced adult mortality selects for slow life histories, which in turn allow the long investment required to grow large brains and the long adult life span that makes growing them worthwhile. Apes (along with some whales and elephants) have the slowest life histories of any nonhuman mammals, and orangutans are the "slowest" apes. Infants are not weaned until they are seven, and in the wild, orangutans may live into their sixties.

[Image and article are from here.]

Inequities big and small can lead people to believe that life is indeed not fair. But how humans respond to unfair situations depends on the social circumstances: inequality among friends and family, for instance, is less disturbing than it is among strangers. The results of a new study indicate that the same is true for chimpanzees, a finding that sheds light on how our sense of fairness evolved.

In the fall of 2003 Sarah Brosnan and Frans de Waal of the Yerkes National Primate Research Center in Atlanta determined that capuchin monkeys don't like being subjected to treatment they deem unjust. In the new work, the researchers tested the reactions of pairs of chimpanzees to exchanges of food that varied in quality. The animals received either a grape, which they coveted, or a less appealing cucumber, and they could see what their partner obtained. In pairs of chimps that had lived together since birth, the individual given the cucumber was less likely to react negatively to the situation than was the short-changed member of a pair that did not know each other as well. Indeed, chimps in the short-term social groups refused to work after their partner received a better reward for the same job. "Human decisions tend to be emotional and vary depending on the other people involved," Brosnan says. "Our findings in chimpanzees implies this variability in response is adaptive and emphasizes there is not one best response for any given situation, but rather it depends on the social environment at the time."

Further experiments to investigate reactions to unfair situations are ongoing at the center in the hopes of understanding why we humans make the decisions we do. "Identifying a sense of fairness in two closely related nonhuman primate species implies it could have a long evolutionary history," Brosnan remarks. The findings will be published in the February 7 edition of the Proceedings of The Royal Society B: Biological Sciences.