Primatology.net

In 1838 Charles Darwin jotted in a notebook, “He who understands baboon would do more towards metaphysics than Locke.” Baboon Metaphysics is Dorothy L. Cheney and Robert M. Seyfarth’s fascinating response to Darwin’s challenge.

Cheney and Seyfarth set up camp in Botswana’s Okavango Delta, where they could intimately observe baboons and their social world. But Baboon Metaphysics is concerned with much more than just baboons’ social organisation- Cheney and Seyfarth aim to fully comprehend the intelligence that underlies it. Using innovative field work, the authors learn that for baboons, just as for humans, family and friends hold the key to mitigating the ill effects of grief, stress, and anxiety.

I spent a couple years studying non-verbal communication in gorillas, so to read news that there’s some breakthroughs in our understandings handedness and communication in apes made me extremely excited. The news originates from Gillian Sebestyen-Forrester‘s latest paper in the journal Animal Behaviour, “A multidimensional approach to investigations of behaviour: revealing structure in animal communication signals.”

Sebestyen-Forrester observed that a right-handed bias for actions that also involved head and mouth movements among gorillas. As you may know, the right side of the body is controlled by the left hemisphere of the brain, which is also the location for language development. Sebestyen-Forrester’s hypothesis is that this handedness bias offers major clues as to how language developed in humans. Gorillas deploy a wide range of non-verbal communicative behaviors, such as facial expression, eye gazes and manual gestures, and tactile signals (like grooming and huddling which are used for social cohesion). In my own experiences, I quickly came to learn what a lip-smack, pursed lip, chestslap, purr, etc. meant.

Gorilla Social Play

But I digress, Sebestyen-Forrester tested her hypothesis by recording the behaviors of a female gorilla mother and her infant, along with their social network at the Port Lympne Wild Animal Park in Kent, United Kingdom. She coded the results and noted that behaviors that involved head and mouth movements correlated with right handedness.

This multidimensional method evaluates all synchronous physical actions of the body in a reciprocal manner. And her analysis did reveal a coordinated physical action, thus demonstrating differences in lateral motor activity. She understands this observation to be ethologically valid to extend that animals with the closest genetic link to humans would express communication skills with some similarities to human.

G FORRESTER (2008). A multidimensional approach to investigations of behaviour: revealing structure in animal communication signals Animal Behaviour DOI: 10.1016/j.anbehav.2008.05.026

Also in the latest Current Biology and first shared by John Hawks is news that may shakeup what you understood was unique to bonobo behavior, that they didn’t hunt other primates. We know that some bonobos eat rodents and small antelopes, albeit infrequently, but for quite sometime we assumed they didn’t consume other primates because they seemed to be placid maternally structured social beings.

The title of the new paper spills all the beans, “Primate hunting by bonobos at LuiKotale, Salonga National Park.” As I just mentioned, bonobos have been popularized by many to be a peace loving species, particularly because of the lack of male dominated social system and far less documented occurrences of physical violence. Such observations have often been used to explain the relative absence of hunting and meat eating in bonobos. In the words of New Yorker writer Ian Parker, bonobos are [were],

“equal parts dolphin, Dalai Lama, and Warren Beatty,”

But earlier this year we got a glimpse into the more devious carnivorous behavior of bonobos, when one of the co-authors of the current paper, Gottfried Hohmann, and another research published in Folia Primatologica, “New Records on Prey Capture and Meat Eating by Bonobos at Lui Kotale, Salonga National Park, Democratic Republic of Congo,” their observations of the presence of monkey finger bones in bonobo fecal samples. In the new Current Biology paper Hohmann and Martin Surbeck publish their observations of bonobos hunting diurnal, arboreal and group living primates at LuiKotale in the Salonga National Park, Democratic Republic of Congo.

The following table from the paper summarizes their observations:

Table 1: Bonobo Monkey Hunts at LuiKotale

The results show us that there were 5 attempts, and 2 of the 3 successful hunts were made by females. Among chimpanzees, females have been rarely been seen taking an active part in hunting parties. But these two female bonobos rocketed up into the trees and attacked their monkey prey just as effectively as the males. I share Frans de Waal‘s opinion that this study is a milestone piece and changes our very foundation of bonobo social organization and socio-ecology.

But hunting may not be a ubiquitous behavior among all bonobos. As Hawks points out,

“at other field sites the bonobos interact in different ways with monkey species, ranging to mutual grooming.”

In fact, bonobos have been observed playing with baby black-and-white colobus monkeys and been seen engaging in grooming behavior with red colobus monkeys, much like adult chimpanzees hunting baboon babies that their offspring were playing with just days earlier. Bipolar anyone?

Surbeck M, Hohmann G. 2008. Primate hunting by bonobos at LuiKotale, Salonga National Park. Current Biology 18, R906-R907. DOI:10.1016/j.cub.2008.08.040

Klaus Zuberbühler and team published his report of blue monkey vocalizations in the Royal Society’s journal Biology Letters. The paper is titled, “Male blue monkeys alarm call in response to danger experienced by others.” I don’t have access to the journal, nor am I willing to pay $50 for the privileged to read it. If anyone has access to Biology Letters and is kind enough to send me a copy of the paper, I’d be more than grateful. In lieu of the primary source, I’ll be summarizing what Lauren Cahoon, from ScienceNOW Daily News, reported on it.

Blue Monkeys (Cercopithecus mitis stuhlmanni)

Klaus and team observed and recorded the behaviors of male blue monkeys (Cercopithecus mitis stuhlmanni) which live in the Budongo Forest, Uganda. Blue monkeys make two vocalizations. Lauren describes them as,

“predator-specific calls: the “hack,” a low, gagging sound that warns about eagles, and the “pyow,” which sounds a bit like a laser gun and warns about more general dangers on the ground, such as leopards.”

The meanings behind the hack and pyow have been largely interpreted as a basic “watch out” warning call. In this new paper, Klaus and team have shown that the frequency of calls indicate the urgency of the danger. In other words, male blue monkeys yelled more frequently if members of their group were close to a crowned eagle. But, if they were further away from the danger the monkeys would lessen the number of calls. They found this out by playing the

“recordings of hacks and pyows from a loudspeaker near blue monkey troops, which are usually made up of a lead male and about 10 to 40 females and young. The recorded sounds prompted the lead male to follow up with his own alarm call, and he typically repeated the cry about 23 times. However, if a female or baby was close to the loudspeaker–the “predator”–the males gave an average of 42 cries. It didn’t matter how close the male was to the danger; he sounded the red-alert alarm only when the females and young appeared to be at risk.”

This behavior suggest that blue monkey males are concerned of any threat to their group, regardless of the impact it to his own direct well-being. Gregory Radick generally agrees but suggests that its less of a group specific reaction and more of a highten level of fear. Of course that hasn’t come without criticisms, because many don’t believe monkeys to be so selfless. Michael Owren thinks that the males are simply more emotional because they are in the proximity of females.

Two years ago, Klaus Zuberbühler and Kate Arnold reported on this behavior in male putty-nosed monkeys (Cercopithecus nictitans) , a close relative of the blue monkey. Their paper was published in Nature, under the title, “Language evolution: Semantic combinations in primate calls.” Male putty-nosed monkeys also make two distinct vocalizations. The frequency and sequence of these calls was also understood to be a danger specific response.

If you’re curious to listen to what the hacks and pyows of male putty-nosed monkeys sound like, listen to these sound bites:

Arnold, K., Zuberbühler, K. (2006). Language evolution: Semantic combinations in primate calls. Nature, 441(7091), 303-303. DOI: 10.1038/441303a

This year marks the 60th anniversary of the founding of primatology in Japan, thanks to the works of Kinji Imanishi. Current Biology hosts an essay by Tetsuro Matsuzawa and William McGrew, which reviews Imanishi’s contributions to the field. The essay can be found at this link, “Kinji Imanishi and 60 years of Japanese primatology.”

I’m not too certain about Imanishi’s education. The piece indicates he was trained to be an entomologist. I deduce he specialized in ecology and animal behavior, because the review says he used to study Mongolian horses before he focused on primates. After his shift, Imanishi spent the rest of his life investigating the origins of human society by observing primates.

Anyways, the piece explains the various research projects after he started studying primates. This was three years after the end of the Second World War. Imanishi established several methodologies such as individual recognition, habituation and long-term observations, which are now standard techniques in the study of nonhuman primates.

Imanishi’s research also gave us insight to the mating habits of Japanese monkeys, their matrilineal societies, social hierarchies, and most importantly — the potato-washing behavior that is considered a proto-cultural behavior. You may have not known this, but this behavior, recorded by Satsue Mito, a student of Imanishi, in September 1953, is the first documented example of a cultural phenomena in nonhuman animals.

In February 1958, Imanishi traveled to Gombe, two years before Jane Goodall began her research. The photo below is from March 6th, 1958, where Imanishi (center) is pictured in Uganda, observing gorillas.

After his trip, he met up with Clarence Ray Carpenter, another primatology pioneer. Despite the death of Carpenter’s son against the Japanese during WWII, Imanishi was welcomed — a true testament of how science prevails. Imanishi gave the inaugural issue of Primates to Carpenter. Imanishi meet up with Louis Leakey and Sherwood Washburn, two big names in anthropology.

Imanishi was a true academic. He was inspired by other academics like Einstein, which motivated him to understand the world around him. If you want to know more about Imanishi, I recommend you check out this digital archive of his field notes.

Matsuzawa, T., McGrew, W.C. (2008). Kinji Imanishi and 60 years of Japanese primatology. Current Biology, 18, R587-R591.

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.

I’m scouring the American Journal of Primatology for a paper on gorillas using tools as weapons in the wild. National Geographic News says the paper is out, but I can’t find it anywhere in the early edition nor in the current issues. I’ll continue looking, but in the mean time here’s what we got to run on (and it ain’t much)

“Researchers [doing a three year study of Cross River gorillas (Gorilla gorilla diehli)] in Cameroon have documented three cases in which the [gorillas] threw clumps of grass or tree branches at humans.”

The people who documented the behavior suggest that the gorillas possibly learned their unusual behavior from interactions with humans. Captive gorillas have been documented picking up stone throwing from their chimpanzee neighbors, so it’s not too improbably that wild gorillas could pick up grass and branch hurling from human neighbors. How did these gorillas learn the behavior? Could it be possibly due to mirror neurons? Conveniently this is a perfect transition into an upcoming PNAS paper on tool use and mirror neurons in macaques, that was announced in this ScienceNOW news article,

“To investigate how the brain performs this sleight of hand, [the team] recorded brain activity in two macaque monkeys. Each was trained for 6 to 8 months to grasp items of food with pliers. The team documented the activity of 113 neurons in F5 and in a brain area called F1, which has also been implicated in the manipulation of objects. The researchers first established the brain’s firing sequence when the monkeys grasped only with their hands. The experiment was then repeated while the monkeys used normal pliers that required first opening the hand and then closing it to grasp the food. The same neurons fired in the same order. Remarkably, the same neurons also fired, in the same order, when the monkeys used “reverse pliers” that required them to close their fingers first and then open them to take the food.”

The research is coming from the University of Parma which seems to be specializing in this sorta research because about a year and half ago they documented mirror neurons role in mimicry. In the new paper, the researchers,

“conclude that when learning to use a tool, the pattern of neuronal activity is somehow transferred from the hand to the tool, “as if the tool were the hand of the monkey and its tips were the monkey’s fingers.” As for how the same neurons could affect both the opening and the closing of the hand, the team speculates that they may be connected with other sets of neurons that more directly control these movements. The authors also point out that area F5 is rich in so-called mirror neurons, a type of nerve cell discovered earlier… that fires both when a primate performs an action and when it observes another individual doing the same thing. Mirror neurons in F5, the authors suggest, may be involved in this transfer process as a monkey learns how to use a tool by watching others.”

The first observations of gorillas using tools in the wild was made a couple years ago, and last year we saw (albeit not too convincingly) a chimp fashioning a spear to hunt, so I’m not too surprised about this news… I just wanna see it!

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 following video is a bit dated, it’s from 2004… but still I’m sharing it with you because it is very informative and rare. The video is of  Susan Savage-Rumbaugh’s TED talk, in which she presents human traits and behaviors in bonobos, specifically the bonobo that made her famous, Kanzi.

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.