Ngogo blog alert: las aventuras de don ernesto

"Don Ernesto" is a research assistant at the Ngogo chimpanzee field site in Kibale National Park, Uganda. He has a very fun blog full of gorgeous photos and funny anecdotes from his time in and around Ngogo. Thanks to Carol RL for the link! - MA

las aventuras de don ernesto blog

Dr. Langergraber’s kids. You can’t tell from the smiling faces in

this photo but Kip just kicked all their asses at soccer.

Chimps Eat Dirt, Leaves to Fend Off Malaria

From National Geographic News
by Scott Norris

Chimpanzees in Uganda swallow mouthfuls of dirt to "self medicate" against malaria, according to a new study.

Clay soils consumed by both chimps and humans in Uganda's Kibale National Park contain high concentrations of the mineral kaolinite, a main ingredient in some anti-diarrheal medications.

Experts had previously suggested that chimps ate the fine-grained clay to help ward off intestinal ailments or to obtain added minerals in their diet.

But a French team recently observed that the chimps eat dirt before or after consuming leaves from the Trichilia rubescens plant, which contains potent medicinal chemicals.

Eating the bitter vegetation alone gives the chimps no health benefit, researchers say.

Instead the plant's malaria medicine is activated when fine soil particles bind with chemicals in the leaves.

Chimps often select dirt that has been exposed on the roots of newly fallen trees, added study co-author Sabrina Krief, of the Muséum National d'Histoire Naturelle in Paris.

"This may be to avoid worms, bacteria, and stones," she said.

Krief and colleagues described the research online in the January issue of the journal Naturwissenschaften.

In humans, soil consumption—or geophagy—has often been viewed as a sign of metabolic disorder or even mental illness.

But the practice is relatively common among animals and is now understood to yield important health benefits.

In parrots and macaws, for example, clay particles are thought to help neutralize toxins present in some favored food sources.

Soil-eating may also provide a soothing coating to the animals' digestive tracts.

In Uganda, however, Krief and colleagues suspected that the chimps were eating soil for other reasons than simply to combat indigestion.

Like humans, chimps can suffer the potentially fatal effects of malaria, although the types of Plasmodium parasites that cause the disease in chimps are different from the four known to infect people. (See a close-up image of malaria parasites attacking a human's red blood cells.)

In previous laboratory studies, Krief's team had found that extracts of the Trichilia plant were effective in fighting the parasite that causes malaria in chimps.

"I noticed that the chimps often eat soil just before or after eating Trichilia leaves," Krief said. "I wondered what might be the effect of mixing the two substances."

To investigate, Krief and colleagues constructed a laboratory model that duplicated chimpanzees' chewing and digestion.

The researchers ground up leaves and soaked them in an acid solution similar to the chimps' digestive fluids. The mixture was then tested for its ability to kill the malarial parasite.

Solutions of artificially digested leaves without soil showed no anti-malarial activity.

But when samples of the soil consumed by the chimps were added to the mix, the researchers found a strong disease-fighting effect.

Chimps and other apes may treat themselves for a variety of ailments by consuming plants, earth, and other materials, experts say.

In another part of Africa, chimps are known to swallow certain leaves to help rid themselves of intestinal parasites.

Previous work by Krief and others had shown that of the 163 plant species Kibale chimps are known to eat, at least 35 are used in humans' traditional medicine.

"The shared use of plants by humans and apes shows how the tropical forest is a unique resource for wildlife, local communities, and western medicine," Krief said.

Jim Moore is an anthropologist at the University of California, San Diego, who was not involved with the new study.

"It's been known for a long time that chimpanzees selectively eat certain plants in ways and at times that only really make sense if they are self-medicating," Moore said.

"This paper is the first I'm aware of to suggest synergistic action of soil and a putatively medicinal plant, and that's important."

But Moore noted that the anti-malaria effect has only been shown in the researchers' model and not yet in living chimps.

"It isn't clear that chimpanzees are seeking the synergy [between leaves and soil]," Moore said. "The paper isn't persuasive in eliminating other hypotheses for geophagy."

Very Important Scientist of the Month (again): Kevin Langergraber

Dr. Langergraber and colleague's new paper in PLOSone entitled "The Genetic Signature of Sex-Biased Migration in Patrilocal Chimpanzees and Humans" came out this week.

Click on the title below to read the open-access article:
The Genetic Signature of Sex-Biased Migration in Patrilocal Chimpanzees and Humans
Kevin E. Langergraber, Heike Siedel, John C. Mitani, Richard W. Wrangham, Vernon Reynolds, Kevin Hunt, Linda Vigilant

For other papers from our lab, go to our lab webpage

Very Important Scientist of the Month - Kevin Langergraber

Original Paper in PNAS can be found here

From NewScientist.com

Chimp cooperation goes beyond family

Nepotism is known to be important in chimpanzee society, but male chimps' ability to cooperate extends beyond family connections, new research reveals.

This extra level of sophistication is yet another way in which the social behaviour of chimps parallels that of humans.

Kevin Langergraber, an anthropologist at the University of Michigan in Ann Arbor, US, and colleagues recorded alliances, meat-sharing and other cooperative behaviour among 41 male chimps in Kibale National Park, Uganda.

The team also genotyped each animal to measure how closely they were related. Over a period of seven years, and over 5000 hours of observations, they observed 753 aggressive coalitions - where they cooperated to fight enemies – and 421 instances of meat sharing.
Selfish reasons

Chimps who shared a mother were far more likely to cooperate with each other. In contrast, there was no evidence that the same applied to chimps with a shared father. This is probably because fathers do not stay with their offspring, so a chimp has no easy way to recognise his paternal brothers.

However, since maternal brothers were rare in this population, most of the cooperating pairs were unrelated or only distantly related.

Extensive cooperation among non-relatives suggests that chimps do it for selfish reasons, with the expectation that favours will be reciprocated, says Langergraber. Human societies use cooperation with similar motives – another behaviour shared with our primate cousins.

Journal reference: Proceedings of the National Academy of Sciences (DOI: 10.1073/pnas.0611449104)

Update:
More pop science articles about Kevin's work:
* National geographic's report
* The Why Files article
* New Scientist article in Italian
* Polit.ru Russian article