Primatology.net

Even though I’ve been posting a lot on tool use lately, I’m sure you will appreciate this new study. The new study, “Invention and modification of a new tool use behavior: ant-fishing in trees by a wild chimpanzee (Pan troglodytes verus) at Bossou, Guinea,” has been published in the most recent issue of the American Journal of Primatology. The writeup is very simple and informative, which is great because I consider this a very important paper in figuring out the origins of tool use and the intricacies of primate behavior.

The scope of this paper is a report on tool use seen in a male chimpanzee from Guinea. Tool use has been documented in several other wild chimpanzee societies, most notably was Goodall’s observations of Gombe chimps using tools. Since then other researchers have seen other wild chimps use tools, particularly using rocks to crack nuts open, and using twigs and sticks to fish or dip for ants. Ever so recently, we read and saw a Fongoli chimp hunt with a makeshift spear.

The clincher behind chimpanzee tool use in the wild use has been that it seems to be localized within the group that the behavior is observed in. This has gotten many researchers to hypothesize that this is some group specific behavior, a cultural trait per say. Researchers had no idea how tool use behaviors emerged in these respective groups, nor how long they have been practicing tool use.

In this new study, JJ, the male chimpanzee was the only chimpanzee in his group seen selecting for sticks used to fish for ants in a two year time period. This group of chimpanzees from Bossou has been studying for 27 years and this behavior has never been observed before. So his tool use tendencies seem to be novel amongst this group. Throughout the two years of observation, JJ progressively modified the optimal fishing stick, selecting for shorter and shorter ones. This indicates that JJ learned the characteristics of the best tool, one that would yield more ants.

Unfortunately, no observation has been made of JJ transmitting this behavior to other Bossou chimps. But it does indicate several thing… tool use can independently arise in chimpanzees, regardless of the fact that the group as a whole practices tool use or not. Also, it provides an insights into the cognitive capacity of wild chimps, like JJ, to problem solve and modify their behavior.

Yamamoto, S., Yamakoshi, G., Humle, T., Matsuzawa, T. (2008). Invention and modification of a new tool use behavior: ant-fishing in trees by a wild chimpanzee (Pan troglodytes verus) at Bossou, Guinea. American Journal of Primatology DOI: 10.1002/ajp.20544

It has been far too long since I’ve updated this blog. I apologize, there certainly has not been a lack of material to share — just a lack of time and overemphasis on Anthropology.net, which is totally my bad, I don’t intend to neglect this site again.

Anyways, photographer Frans Lanting recently travelled to take photos of the Fongoli chimpanzees in Senegal. He was on NPR yesterday to share his experiences. The Fongoli chimps, if you don’t remember, are the ones that have been observed to hunt with spears. Jill Pruetz actually was the one to see this behavior and I covered this news last year. I was a bit skeptical, but it seems like Lanting and Pruetz were able to observe this behavior again. From the NPR article,

Lanting and Pruetz observed the primates fashioning spears from tree limbs to capture bush babies, small mammals that hide deep inside hollow trees.

“No one has ever seen that before in any other chimps elsewhere,” Lanting says.

The Fongoli chimps often displayed behaviors akin to those of early humans.

“There is very little fundamental difference in my opinion between how these chimps live and how our very earliest ancestors lived,” Lanting says. “It’s just like looking at human beings. I regard these chimpanzees as very shy, private people.”

Like humans, the male chimps also seem to have a bit of a rhythmic bent; Lanting observed them drumming on hollow baobab trees as a way of impressing potential mates and intimidating rivals.

It took several months for the Fongoli chimps to begin accepting Pruetz and Lanting, who says they wore the same clothes every day so that the animals could become accustomed to their presence.

On days that the chimps let their guard down, Lanting says, he and Pruetz were able to observe behaviors that “are all confirmation to the fact that the boundaries between humans and chimps are really quite fuzzy.”

Be sure to check out the 9 minute long audio interview with Lanting.

A new Current Biology paper has documented what I’ve been following attentively sine 2006, the effect of exposure of human pathogens to great apes in the wild. The paper, “Pandemic Human Viruses Cause Decline of Endangered Great Apes,” is out on early advance release.

In order to thoroughly study the epidemiology of two communities of chimpanzees at the Taı National Park, a multidisciplinary approach involving behavioral ecology, veterinary medicine, virology and population biology was taken to track human disease. Tissue samples taken from chimpanzees that had died in a series of outbreaks dating back to 1999 tested positive for two human respiratory viruses that are major sources of human infant mortality in the developing world, namely human respiratory syncytial virus and human metapneumovirus. Viral strains sampled from the chimpanzees were closely related to pandemic strains concurrently circulating in human populations as far away as China and Argentina, suggesting recent introduction from humans into the chimpanzees.

The multidisciplinary research revealed an important distinction in issues revolving around ape conservation,

“The research project has however also had strongly positive effects. Longitudinal surveys showed that the presence of researchers had suppressed poaching activities in the surrounding area. Consequently, chimpanzee densities at both the research study site and a nearby chimpanzee tourism site were much higher than would be expected given their accessibility to poachers.”

In the past, I’ve covered on how the pathogens behind the diseases, Yaws, Ebola, and Anthrax have decimated ape populations. These three pathogens are affiliated with human society, specifically population density and sanitary as well as animal domestication issues. This new study specifically focused on the impact of human viruses to which wild great apes have little to none acquired immunity.

Here’s three posts where I covered the other diseases:

• Yaws disease among gorillas and the affect it has on reproductive success
• Ebola virus has decimated over 5,000 gorillas
• The role of Anthrax in the Great Ape Die-Off

Last month Ayumu and five other chimpanzees made the news because of their outstanding cognitive performance. They even beat out college students in their tests. The results of the study was reported in Current Biology, “Working memory of numerals in chimpanzees.”

If you don’t believe me check out the video of Ayumu rocking the test:

Very impressive performance. Luminosity Games has remade Ayumu’s game. If you wanna try to see if you’re any better than Ayumu, give it a shot here. I’m not very good at the game.

The collective understanding of Miocene African primate evolution, especially ape evolution, is generally unfounded. Why? Because the fossil record is spotty, there are only a handful of primates from the Miocene. The Miocene lasted from 23.8 to 5.3 million years ago, and a lot of interesting things happened in the ape lineage during that time. The molecular evidence tells us that gorillas diverged about 10 to 8 million years ago, and chimpanzees as early as 5 million years ago. But because we don’t have many fossils from that period, it’s hard to see what these apes looked like during this period.

Suffice to say, it is always welcoming to read of a new publication announcing a new Miocene ape. We’ve had the pleasure to do so, with the introduction of Nakalipithecus nakayamai, a Miocene Ape from Kenya. PNAS is carrying the paper now, under the title, “A new Late Miocene great ape from Kenya and its implications for the origins of African great apes and humans.” The paper is written by both Japanese and Kenyan academics.The fossils of N. nakayamai were found over a decade ago in a fossil bed called Nakali, which is about 40 kilometers west of Maralal. These fossils make up the holotype of the species, which is the scientific way of saying this is the type specimen. A total of 11 fossils make up this specimen, including a right mandibular fragment with M1–M3, left I1, right C*, right P3, left P4, right M1, right I2, left P3, right P4, right M, left M, and a left dp.

As you can see, these are all teeth. Teeth are especially important in understanding evolution because they offer more resolution of information than other parts of the skeleton.

The teeth are similar in size to modern orangutans and gorillas, some of the larger great apes. The teeth differ from other known species of apes in having a much different upper canine. I’m not gonna rehash how it’s different because it requires an intimate understanding of tooth anatomy, morphology, and terminology. Just take my word for it, it’s a much different canine, as long as it is broad. Have a look for yourself,

The premolars are also different. They are elongated but have reduced cusps.The authors indicate that N. nakayamai is similar to another genus of Miocene ape, Ouranopithecus. However, the differences from Ouranopithecus are in thinner enamel and less inflated cusps in the molars. The authors compare the fossils to other Miocene apes,

“N. nakayamai is distinguished from Ankarapithecus, Sivapithecus, and Khoratpithecus by its large size… more gracile mandibular body… N. nakayamai is [also] different from Dryopithecus in its large size.”

Other than Samburupithecus kiptalami, there aren’t many mid-Miocene apes from Africa known at this time. There is a relatively larger number of Miocene ape fossils found from Turkey and Greece, which has gotten a lot of people, ahem David Begun, to think that apes made a rendezvous out of Africa and into what is now the Middle East and parts of Europe. With this new genus and species, Nakalipithecus, we now see that at least three diverse species of non-cercopithecoid catarrhines survived through the Middle to Late Miocene in Africa, and that suggests a less likelihood that hominoid primates were absent from Africa and were reintroduced from Eurasian populations.

In August, 2007 Gen Suwa and crew reported on a new Ethiopian Miocene Ape, Chororapithecus abyssinicus. And today, Kenyan and Japanese paleoanthropologists have published their study of a fragment of a mandible and 11 teeth, dating back to between 9.8 and 9.88 million years, which was found 2005.

The fossils were unearthed in volcanic mud flow deposits in the northern Nakali region of Kenya. It has been dutifully dubbed Nakalipithecus nakayamai, the genus assigned after the area it was found in while the species is named after Japanese geologist Katsuhiro Nakayama who died while working on the project. Comparisons of the size of the teeth of N. nakayamai shows that it was comparable to a modern female gorilla and a female orangutan. It also resembles another Miocene ape Ouranopithecus macedoniensis, from Greece but several aspects of the dentition indicate a less specialized diet than Ouranopithecus, and place Nakalipithecus in a genus of its own.

I’ll report more on this when I get my hands on the paper.

I’ve been unable to post on a lot of important primatology news as of late, I’ll try to catch up this weekend.

But I’m making time to quickly announce that Washoe has died. She was 42 years old and one of the first apes that was taught sign language, about 300 signs. She was known for her sweet, endearing soul. She even made signs for words she didn’t know.

Rest in peace, Washoe.

Boing Boing is on fire, first they post on Bill Bass and now they post on a new study from Smithsonian which reviews the,

“traits that [chimpanzees and humans] share, like altruism and vengeance, and those we don’t, like spite and most social learning skills, are shedding light on what it means to be human.”

So check out the article, “Animal Insight.” It is a pretty good review.

A PLoS One study of chimpanzees at Bossou in Republic of Guinea, shows that the male chimpanzees raid farms and orchards for fruit that they steal and bring back to the females. In exchange, the males shared their fruity booty with the females in a food-for-sex trade.

The photo to your right shows one of the sneaky males climbing a cultivated papaya tree to harvest some fruit. The look on his face is priceless.

Of all the evolutionary psychological studies involving chimps I shared with you this past week, this one “Chimpanzees Share Forbidden Fruit,” is the most remarkable. Here’s the abstract, the full text of the article is openly accessible for anyone to enjoy reading in first hand,

“The sharing of wild plant foods is infrequent in chimpanzees, but in chimpanzee communities that engage in hunting, meat is frequently used as a ‘social tool’ for nurturing alliances and social bonds. Here we report the only recorded example of regular sharing of plant foods by unrelated, non-provisioned wild chimpanzees, and the contexts in which these sharing behaviours occur. From direct observations, adult chimpanzees at Bossou (Republic of Guinea, West Africa) very rarely transferred wild plant foods. In contrast, they shared cultivated plant foods much more frequently (58 out of 59 food sharing events). Sharing primarily consists of adult males allowing reproductively cycling females to take food that they possess. We propose that hypotheses focussing on ‘food-for-sex and -grooming’ and ‘showing-off’ strategies plausibly account for observed sharing behaviours. A changing human-dominated landscape presents chimpanzees with fresh challenges, and our observations suggest that crop-raiding provides adult male chimpanzees at Bossou with highly desirable food commodities that may be traded for other currencies.”

If you don’t believe what you’re reading the authors provided two video clips showing some sly and slick male chimp entering what is obviously and occupied by humans (because of the buildings) climbing a tree, stealing fruit, and making a mad dash as if he were a bandit. Then he shares an intimate moment with his lady friend, munching on some fruit.

I’ve edited the clips together and put them up on YouTube for all y’all who can’t play the file types they provided.

Right on the heels of yesterday’s two primate psychology posts involving chimps comes news that captive chimpanzees have been observed to flip through National Geographic magazines that calm them down. I wouldn’t have found this if it weren’t for Neatorama‘s post. The observations have been written up and published in Biology Letters. Here’s the paper, ” Chimpanzees use self-distraction to cope with impulsivity.”

For the most part chimps are really rambunctious primates, especially in captivity. They are always impulsive and intense, but psychologists Theodore Evans and Michael Beran of the Georgia State University saw a different animal when they were given magazines to preoccupy themselves with after exciting them with candy.

Their experiment involved observed four adult chimpanzees that were first given a candy dispenser. The candy was given to them every 30 seconds but as soon as the apes reached to get the accumulated candy, the dispenser stopped delivering. This sort of teasing tested the chimps’ patience; a greater award was offered if they resisted their impulses, they would earn a greater award.

And when they were given a set of toys, like magazines, toothbrushes, and tubes, they were significantly better at coping with temptation when they could entertain themselves. Without toys, the chimps could only hold out for about 7 minutes to get a measly 11 candies but when toys were around they waited almost 10 minutes to get a total of 17 candies. Evans remarks,

“The magazines included some National Geographic, Entertainment Weekly, and Atlanta food and wine circulars, among others. The chimps would slowly page through the magazines, probably looking at the pictures—research suggests that they perceive pictures as real objects like humans do. They used the toothbrushes as we would. They appeared to enjoy the bristle texture in their mouth and on their teeth.”

And Beran,

“Humans like to think that they can control themselves better than can animals, and yet this type of research suggests that the story is not that simple.”

So in conjunction with the expectation of rational behavior and cognition skills, here’s another once-thought-of-human-only behavior that is documented in humans.