miércoles, 28 de abril de 2010

Chimps Confront Death in Human-Like Ways

From sitting quietly by terminally ill fellow chimps to tossing and turning at night, chimpanzees exhibit familiar responses to death, observations show.

By Jennifer Viegas | Mon Apr 26, 2010 12:00 PM ET


  • Chimpanzees confront death in human-like ways, including attempting resuscitation.
  • The animals'awareness of death is probably more developed than previously thought.
  • Researchers suggest chimpanzees be allowed to die naturally in their groups to permit final goodbyes.

From holding deathbed vigils to comforting the dying, chimpanzees face death in human-like ways that indicate their awareness of death is probably much more developed than previously thought, suggest two new studies.

The papers, both published in the journal Current Biology, provide rare, intimate glimpses of chimpanzees dealing with death.

For the first study, scientists observed how three adult chimpanzees reacted when an elderly female, named Pansy, gradually passed away in an indoor enclosure at Blair Drummond Safari Park in Stirling, Scotland. The over 50-year-old Pansy had grown increasingly lethargic before lying down on the floor one day after eating.

"In the days before Pansy died, the others were notably attentive towards her, and they even altered their routine sleeping arrangements to remain by her, by sleeping on the floor in a room where they don't usually sleep," lead author James Anderson told Discovery News.

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Blossom, another elderly female, and Pansy's daughter, Rosie, both stroked and groomed the dying Pansy, and sometimes just sat, subdued, beside the elderly female. Blossom's son Chippy checked to see if Pansy was alive by manipulating her arms and trying to open her mouth.

All of the chimps tossed and turned at night, much more than normal, during the dying female's final few days.

"As she died, all three were closely gathered around her, and they paid especially close attention to her face," said Anderson, who is in the Psychology Department at the University of Stirling. "After some lifting and shaking of her head and shoulders, all three moved away from her, and there was no more such contact at all."

After Pansy died, however, overhead video cameras captured Chippy jumping onto the platform with Pansy's body. He leapt into the air, brought both hands down and pounded on Pansy's torso. He later sat by the corpse, and gently removed straw from the face.

"It is possible that it was an attempt to arouse Pansy, or a serious test of whether she was able to respond," Anderson said.

For the second study, Dora Biro of the University of Oxford and colleagues witnessed the deaths of five members, including two infants, of a semi-isolated chimpanzee community that researchers have been studying for over three decades in the forests surrounding Bossou, Guinea. The dead succumbed to a flu-like illness possibly originating in humans.

After their two infants died, chimpanzee mothers Jire and Vuavua continued to carry and groom their offsprings' lifeless bodies for up to 68 days. By the time the corpses were finally abandoned, the bodies had mummified and developed an "intense smell of decay."

While it remains unclear if the mothers were aware that their infants had died, the researchers suggest biophysical changes that prepare mothers for childcare after birth "may have contributed to a gradual letting go" of the remains.

"Intriguing parallels may exist with physiological and psychological changes experienced by human mothers, in whom the absence of cessation of breastfeeding may cause exaggerated desires to hold their infant (after it has died)," the researchers wrote.

"Certainly in humans, the loss of loved ones is an immensely painful experience, and the loss of a child perhaps almost inconceivably so," Biro told Discovery News, adding that "we probably experience feelings of a 'refusal to let go' even if we don't act on it in the same way as these mothers did."

Humans, she said, tend to "hold onto objects that remind us of the dead person instead. We feel simply unable to throw them away, often for long periods after death, and these can be extremely emotive for us."

In light of all of the findings, Anderson and his colleagues suggest it might be better to not remove ailing elderly or terminally ill chimpanzees from their groups before they die, if the chimps are not contagious. At present, such individuals are often taken away and put to sleep.

"In some cases," Anderson and his team conclude, "it might be more humane to allow elderly apes to die naturally in their familiar social setting than to attempt to separate them for treatment or euthanasia."

Humans Have a Lot to Learn From Bonobos, Scientist Says

This Behind the Scenes article was provided to LiveScience in partnership with the National Science Foundation.

Primatologist Brian Hare wishes more people could discover what bonobos can teach us about human nature. "I really think they are the smartest ape in the world," he said. "We have a lot to learn from them."

Bonobos are genetically close to humans, yet most people know very little about them. Through his ongoing research, Hare hopes to change that.

"Bonobos really are our less familiar cousin that we have kept at arm's length," Hare said. "The general public is so unfamiliar with them that even many reporters who have interviewed me have written in their stories that they are bonobo 'monkeys,' not realizing they are apes — like us. So it is great when thebonobos can have some attention."

Bonobos are often confused with chimpanzees, but actually are quite different. In looks, bonobos are smaller, with black faces, pink lips and long black hair, neatly parted in the middle. Chimps have low, loud voices, while bonobos' voices are high-pitched.

More significantly, chimps make war, males take charge, and chimps can be quite violent, even to the extent of killing one another. Bonobos, on the other hand, are governed by females, don't ever kill one another, and use sexual activity to maintain a peaceful collective temperament.

Hare, assistant professor of evolutionary anthropology at Duke University, spends several months of the year in the Democratic Republic of Congo, where he studies bonobos. He focuses on their behavior, specifically on how they solve problems and interact with other bonobos.

Recently, he and his colleagues found that bonobos are natural sharers. Their work, published in a recent Current Biology and funded by the National Science Foundation and the European Research Council, described how bonobos enjoy sharing food with other bonobos, and never outgrow their willingness to do so — unlike chimpanzees, who become more selfish when they reach adulthood.

In one experiment, the animals in an enclosure were allowed to keep an entire food pile for themselves or open a one-way door that would allow another bonobo to enter the room to eat with them. Invariably, they opened the door.

"What we found is that the bonobos voluntarily chose to open the door for their neighbor so they could share the food," Hare said.

Another set of experiments, at the Tchimpounga Sanctuary in Congo, compared chimpanzees to bonobos. The young chimps were quite similar to young bonobos in their willingness to share food, but researchers discovered that the chimps became less willing to share as they grew older. Bonobos, on the other hand, continued to share like juveniles even after reaching adulthood, they said.

"It seems like some of these adult differences might actually derive from developmental differences," said Victoria Wobber, a Harvard graduate student who collaborates with Hare. "Evolution has been acting on the development of their cognition."

Hare and his mentor, Richard Wrangham at Harvard, believe bonobos act this way because they always have enjoyed an abundant environment. They typically live south of the Congo River, where there is plenty of food, and where they don't have to compete with gorillas — as chimpanzees must — or with each other.

However, bonobos have human enemies, specifically hunters engaged in the illegal international trade in bush meat. Conservationists are working to rescue bonobos who have been orphaned by these activities, sheltering them in sanctuaries, where they are protected for as long as they live.

"Unfortunately, bonobos are not immune to the bullets of hunters and often fall prey," Hare said. "Their meat is sold in big cities in Congo, but bush meat traders try to sell infants that survive their mothers' deaths as pets. Here in Congo, it is illegal to buy and sell bonobos, so when an infant is discovered in the market, or in the possession of a wildlife trafficker, they are confiscated."

The animals live in a sanctuary called Lola ya Bonobo, located in Les Petites Chutes de la Lukaya, just outside of Kinshasa. "Lola ya Bonobo" means "paradise for bonobos" in Lingala, the main language of Kinshasa.

Lola ya Bonobo cares for more than 60 bonobo orphans. The facility is run by a staff of conservation and welfare experts who "do an amazing job quickly rehabilitating the infant bonobos, so that they quickly recover from the trauma of their capture, and live a very normal and happy life with other bonobos here at the sanctuary," Hare said, adding: "They have a huge 75 acre forest they play in each day."

Many of these rescued bonobos serve as Hare's research subjects. At the sanctuary, Hare and his fellow researchers use experimental techniques to test the bonobos, and observe their behavior. "Essentially, we design fun games that the bonobos can play and enjoy, but at the same time can reveal how they solve problems," he said. "The study published in Current Biology is a great example of how experiments are important to understand the psychology of animals."

After the games, "we let the bonobos back out into their giant outdoor enclosures so they can play with all the other bonobos in the primary tropical forest they live in during the day," Hare added. "Basically, they stay inside for an hour or so, and get a lot of yummy food, and they go back outside."

Born and raised in Atlanta, Hare, 34, was always interested in animals and biology, so a career studying animal behavior, "comes kind of naturally," he said. He went to Emory University, where, among other things, he studied chimpanzees.

"However, I'd always wanted to study bonobos and compare them to chimpanzees," he said. "I did my PhD work at Harvard with Richard Wrangham, who encouraged me to start working in African sanctuaries, like Lola ya Bonobo. This is exciting because our research dollars go to organizations in ape habitat countries working on welfare and conservation efforts."

Hare's wife, Vanessa Woods, is a research scientist in Biological Anthropology and Anatomy at Duke. She is expecting their first child in August, and has written a book about the bonobos, Congo, and their research on bonobos, entitled Bonobo Handshake, scheduled to be released in June by Gotham/Penguin. "I do think it could be a great reference if people want to learn more about bonobos," Hare said. "She detailed a lot of the story about our research — maybe too much detail in some places — a good place to look for embarrassing stories."

Lola ya Bonobo is the largest bonobo captive facility in the world that supports research, Hare said, which enables scientists "to do a number of comparisons between chimpanzees and bonobos that would otherwise be impossible," he added.

Hare is especially pleased that one of his research colleagues, Suzy Kwetuenda, based at Lola ya Bonobo, is the first Congolese student ever to study the psychology of bonobos.

“"Hopefully, she will be the first of many students studying bonobos' behavior and psychology," added Hare, "and that will get average Congolese citizens excited about saving the bonobo, which is only found in their country."

Editor's Note: This research was supported by the National Science Foundation (NSF), the federal agency charged with funding basic research and education across all fields of science and engineering. Any opinions, findings, and conclusions or recommendations expressed in this material are those of the author and do not necessarily reflect the views of the National Science Foundation. See the Behind the Scenes Archive.