Does Chimp x Gorilla Hybrid Exist?

Darren Naish at Tetrapod Zoology posted an interesting post about chimp x gorilla hybrid or the koolo-kamba. Do you think such hybrid exists or these individuals just display a range of "genetic variation" previously unknown to science? Check out Darren's post now, The Yaounde Zoo mystery ape and the status of the Kooloo-Kamba.

Japanese Macaques Floss Teeth

Earlier this year, I blogged about long-tailed macaques (Macaca fascularis) in Thailand using human hair as dental floss to clean their teeth. This behavior gives us an insight to culture transfer as mothers were observed teaching their infants how to floss repeatedly.

In Kyoto, Japan, a Japanese macaque (Macaca fuscata) name Chonpe was observed flossing her teeth using her own hair. She perfected not one, but three flossing techniques.

Lead author Jean-Baptiste Leca told Discovery News that dental flossing could have been a fortuitous yet "accidental byproduct of grooming." Leca, a post-doctoral fellow at Kyoto University's Primate Research Institute, explained that "Japanese macaques sometimes bite into hair or pull it through their mouths to remove external parasites." The hair might have become stuck in Chonpe's teeth, and as she drew the hairs out, "she may have noticed the presence of food remains attached to them". "The immediate reward of licking the food remains off the hair may have encouraged her to repeat the behavior for the same effect in the future," he added.

Chonpe is a middle ranking female with no children. Her only close kin is her mother and her sibling, therefore diffusion of knowledge is somewhat limited to her only sibling. She was observed flossing her teeth about four years ago and had only recently seen this behavior spread among Chonpe's troop. Chonpe was also observed her rolling small stones in her hand while attempting to remove a spine stuck in her palm, so she might be particular an innovative individual, the researchers added.

Chonpe flossing her teeth. Photo by Jean-Baptiste Lena on Discovery News.

Read about the article from Discovery News, Tidy Monkey Flosses Teeth and The first case of dental flossing by a Japanese macaque (Macaca fuscata): implications for the determinants of behavioral innovation and the constraints on social transmission on the journal Primates.

First Molars And Life History In Living African And Asian Apes

Another interesting paper on teeth, specifically the eruption of the first molar (M1), by Jay Kelley and Gary Schwartz from The Institute of Human Origins, Arizona State University (ASU) Since the emergence of M1 correlates with many life history attributes in extant primates, data from this paper can be used to compare the life history among extant primates and also extinct apes and hominins.

"Knowing the age when the first molar appears in the mouths of most primates allows researchers to predict a host of life history attributes, such as gestation length, age at sexual maturity, birth spacing and overall lifespan," said Schwartz. "Humans are unique among primates because our life histories are so slow and thus our molars emerge relatively late. Given that apes are our closest living relatives, understanding the broader context of when the characteristic slower development of humans evolved is of great interest."

"Like annual growth rings inside trees, the cells that produce teeth (both the enamel and underlying dentine) leave behind a trace of their presence, not as annual markers, but as growth lines that appear every day," said Kelley. By slicing the teeth in half, he and Schwartz were able to examine these incremental growth lines in ape individuals that died as their first molars were just erupting into their mouths. "Because teeth preserve this phenomenal internal chronometer, we were able to count up how many days it took the first molars to form," said Schwartz. "In apes and monkeys, first molars start forming very close to the time of birth. As the first molars were still erupting in our specimens, development was incomplete and the final growth line was laid down on the day those animals died. Therefore, by counting backwards from the final growth line to the day of birth, we determined their age at death and thus the age at which that molar was erupting." Using this novel approach, the two scientists were able to mark the age of the gorilla's first molar emergence at 3.8 years, nearly identical to that of a wild chimpanzee's. The orangutan's age at first molar emergence was surprisingly much later, at 4.6 years, which falls closer to the age of approximately 6 years in modern humans.

Read the article, Molars provide insight into evolution of apes, humans by ASU and Dental development and life history in living African and Asian apes from PNAS.

Natural Selection In Great Apes Favor Those With Teeth That Can Handle Fallback Foods

Great apes (orangutan, gorilla and chimpanzee) depend on their teeth to get them through tough times when food is scarce. Natural selection favor individuals with teeth that can process fallback foods, foods that are harder than the great apes normal diet of fruits. The evolution of the thickness of enamel in great apes reflects the mechanical demand of their diet.

"It makes sense if you think about it," says GWU's Paul Constantino. "When resources are scarce, that's when natural selection is highly active in weeding out the less fit, so animals without the necessary equipment to get through those tough times won't pass on their genes to the next generation."

Read the Science Daily article, Among Apes, Teeth Are Made for the Toughest Times and The Influence of Fallback Foods on Great Ape Tooth Enamel by Constantino et al. (2009).

Chimps Observed Using Tools To Cut Food Into Smaller Pieces

From BBC News, chimps from the Nimba Mountains of Guinea, Africa were observed using tools to chop up and reduce food into smaller bite-sized pieces.

Kathelijne Koops and William McGrew of the Leverhulme Centre for Human Evolutionary Studies, University of Cambridge (UK) with Tetsuro Matsuzawa from Kyoto University, Inundate (Japan) observed this behavior and published it on Primates. They found that these chimps use tools to process Treculia fruits, a large volley ball-shaped fruit that is hard and fibrous.

Abstract:

Wild chimpanzees (Pan troglodytes) are renowned for their use of tools in activities ranging from foraging to social interactions. Different populations across Africa vary in their tool use repertoires, giving rise to cultural variation. We report a new type of percussive technology in food processing by chimpanzees in the Nimba Mountains, Guinea: Treculia fracturing. Chimpanzees appear to use stone and wooden “cleavers” as tools, as well as stone outcrop “anvils” as substrate to fracture the large and fibrous fruits of Treculia africana, a rare but prized food source. This newly described form of percussive technology is distinctive, as the apparent aim is not to extract an embedded food item, as is the case in nut cracking, baobab smashing, or pestle pounding, but rather to reduce a large food item to manageably sized pieces. Furthermore, these preliminary data provide the first evidence of chimpanzees using two types of percussive technology for the same purpose.

Do chimpanzees (Pan troglodytes) use cleavers and anvils to fracture Treculia africana fruits? Preliminary data on a new form of percussive technology (free abstract).

Wild Chimps Know What Fire Is ... Kinda, Part II (Link to Jill Pruetz's Paper)

The paper by Jill Pruetz and Thomas LaDuke about Fongoli chimps and their conceptualization of fire is out on the American Journal of Physical Anthropology. As promised, here is the link to the paper, Brief communication: Reaction to fire by savanna chimpanzees (Pan troglodytes verus) at Fongoli, Senegal: Conceptualization of "fire behavior" and the case for a chimpanzee model (only free abstract).

Read the previous post, Wild Chimps Know What Fire Is ... Kinda.

Global Warming Threatens Folivory Primates

Black and white colobus monkey, one of the folivory species threaten by global warming.

A paper by Korstjens et al. (2009) suggests that even an annual temperature rise of 2°C would threaten folivory primates because these species would be forced to spend more time resting than foraging for food. This paper, Resting time as an ecological constraint on primate biogeography, was published online on Animal Behaviour. Here's the abstract:

Time constraints can limit an animal's potential to survive in a given habitat and the maximum size of its group. Many studies have, therefore, investigated the ecological correlates of time allocated to travelling, foraging and vigilance. However, animals spend more time inactive than active, and understanding the determinants of this resting time may provide new insights into the habitat-specific time-budgeting problems that animals face. We analysed the environmental constraints that determine the minimum amount of daytime an average primate has to spend resting, using data from a wide range of ecologically different species. However, total resting time consists of two components: enforced resting time (imposed on the animal by ecological constraints) and free resting time (the time available for allocation to ecologically functional activities). We show that the ecologically important enforced resting time is determined by diet and annual temperature as well as by temperature variation. Our tests of the biological significance of this relationship show that enforced resting time distinguishes between locations that are suitable or unsuitable for particular genera. We show that an annual temperature increase of 2–4 °C would greatly increase enforced resting time, leading to serious time-budgeting problems for many species. The effect of changes to enforced resting time on the biogeographical distribution of species is especially strong for folivorous primates. This study shows that resting time is an important component of animal behaviour that can help us understand extinction risk and geographical distribution of taxa.

Read more about this paper on PhysOrg.com, African leaf-eating monkeys are 'likely to be wiped out' by climate change.

Meat May Be The Reason Why Humans Live Longer Than Apes

 Meat, that's what for dinner.

Ever wonder why humans outlive apes? The answer might be because we eat a lot of meat. Genes evolved in humans to adjust to a meat-rich diet helps fight diseases associated with aging such as cancer, heart disease and dementia. Not to mention, the expansion of brain size in the genus Homo is also attributed to an increase in meat diet. Check out the MSNBC article "Meat may be the reason humans outlive apes" and the paper "Evolution of the human lifespan and diseases of aging: Roles of infection, inflammation, and nutrition" by Caleb Finch on PNAS.

Is Eastern Lowland Gorilla A Hybrid Species?

Over at Lawn Chair Anthropology, Zacharoo discusses whether the Eastern Lowland Gorilla (Gorilla beringei graueri) is a hybrid species of the putative "parental" species, the Eastern mountain gorilla (Gorilla beringei beringei) and the Western lowland gorilla (Gorilla gorilla gorilla). Check out the post, here.

Wild Chimps Know What Fire Is ... Kinda.

Jill Pruetz, an ISU associate professor of anthropology, has been studying savanna chimpanzees at her Fongoli research site in Senegal since 2001. Her new study documents how the chimps understand the fire they encounter in the region. Photo by Bob Elbert, ISU News Service.

A new study by Iowa State University anthropologist Jill Pruetz suggests that savanna chimps (Fongoli chimps) in Senegal have a near human understanding of wildfire and would alter their behaviors in anticipation of the wildfire's movement. Along with Thomas LaDuke, an associate professor of biological sciences at East Stroudsburg University in Pennsylvania, they co-authored the paper, which will be published in the American Journal of Physical Anthropology, 2010 edition. (I will post another blog post with link to the paper once it's published).

According to Pruetz and LaDuke, humans must accomplish three cognitive stages to truly control fire. First, they must have a conceptualization of what fire is and understand its behavior. Second, they must have the ability to control fire, including the containment and manipulation of the fire. Third, they must have the ability to start a fire. The Fongoli chimps seem to have mastered the first stage, according to Pruetz. However, she does not anticipate the chimps to start fire anytime soon due to the constrains of their flexibility.

Read the rest of the article from Iowa State University here.

Taung Child - Virtual Skull

A partial skull and brain endocast of an Australopithecus africanus child. Photo from Australian Museum.

Through the Australian Museum, you can now access the virtual skull of Taung Child, an Australopithecus africanus. This interactive replica includes the partial skull and brain endocast found in Taung, South Africa in 1924. Raymond Dart published this discovery in 1925.

Click here to look at the interactive Taung Child.

December 14th is Monkey Day!

For some of you who doesn't know, every year on December 14th (tomorrow) is Monkey Day. Learn more about this holiday on the Monkey Day official website. The folks responsible for Monkey Day is also behind the blog Monkeys In The News. Go check them out and follow them. Do you know what's the difference between a monkey and an ape?

What will you be doing on Monkey Day? Too bad I threw out my Halloween costume ... I was a sad, confused and wet monkey!

A New Homo Erectus Endocast From China (Zhoukoudian V)

A newly published paper, A new Homo erectus (Zhoukoudian V) brain endocast from China, by Wu et al. (2009) in Proceedings of The Royal Society B is available online for free. Here's the abstract:

A new Homo erectus endocast, Zhoukoudian (ZKD) V, is assessed by comparing it with ZKD II, ZKD III, ZKD X, ZKD XI, ZKD XII, Hexian, Trinil II, Sambungmacan (Sm) 3, Sangiran 2, Sangiran 17, KNM-ER 3733, KNM-WT 15 000, Kabwe, Liujiang and 31 modern Chinese. The endocast of ZKD V has an estimated endocranial volume of 1140 ml. As the geological age of ZKD V is younger than the other ZKD H. erectus, evolutionary changes in brain morphology are evaluated. The brain size of the ZKD specimens increases slightly over time. Compared with the other ZKD endocasts, ZKD V shows important differences, including broader frontal and occipital lobes, some indication of fuller parietal lobes, and relatively large brain size that reflect significant trends documented in later hominin brain evolution. Bivariate and principal component analyses indicate that geographical variation does not characterize the ZKD, African and other Asian specimens. The ZKD endocasts share some common morphological and morphometric features with other H. erectus endocasts that distinguish them from Homo sapiens.

Tim Jones from Anthropology.net has a great write up about the paper, A New Homo erectus (Zhoukoudian V) Brain Endocast From China – Free to Access.

Campbell's Monkeys Language Deciphered

A group of researchers from University of St. Andrews, Scotland argues that Campbell's monkeys (Cercopithecus campbelli campbelli) have a primitive form of syntax after spending months of recording their calls as they response to both natural and artificial stimuli. Lead by Dr. Klaus Zuberbühle, the team found that male's alarm calls are made up of an acoustically variable stem, followed by an acoustically invariable suffix. These calls translate to either a specific alarm call or a non-specific alarm call, depending on the syntax.

I'm not an expert in language and linguistics but these findings are interesting in the development of language and speech in primates. Is there a reason why these monkeys are capable of understanding syntax while apes (such as gorillas and chimpanzees) don't?

Read the New York Times article here.
Campbell's Monkeys Use Affixation to Alter Call Meaning by Ouattara et al., (2009)

This Week In Primatology

While I was away at the AAA meeting in Philadelphia, my inbox was flooded with articles on primates from behavioral to molecular level. Here's whats happening this week in primatology:

Primate study halted by US university: Administrators at Oklahoma State University (OSU) in Stillwater have abruptly cancelled an anthrax vaccine study that would have killed dozens of baboons. Can I tell you how happy I am about this? No animals should suffer for science, not even to find a vaccine for humans.

Did Social Climbing Give Us Bigger Brain? by Urban Ethology. It takes a big brain to scheme and plan, so maybe we can thank Machiavellian Intelligence and our complex social system for that big brain of ours.

Monkeys Recognize Their Pals In Photos.Tufted capuchin monkeys (Cebus apella) were tested to see if they have facial recognition using photographs. Pokorny and de Waal (2009) published their findings in the online early edition of Proceedings of the National Academy of Sciences (PNAS). Monkeys recognize the faces of group mates in photographs (free abstract).

Social Conformity Not Unique To Humans. Another study on capuchin monkeys (talk about conforming, LOL). Dr. Marietta Dindo and Professor Andrew Whiten of the University of St Andrews show that capuchin monkeys would copy behaviors of other individuals. Not only do they copy other individual's behavior, they would copy behaviors that are the most popular in the group.

Why Some Monkeys Don't Get AIDS. Yea, why? It's not fair! Two studies reveal why some monkeys don't get AIDS and possibly identifying genes that are related to the progression or resistance to AIDS. Nonpathogenic SIV infection of African green monkeys induces a strong but rapidly controlled type I IFN response (Jacquelin et al., 2009) and Global genomic analysis reveals rapid control of a robust innate response in SIV-infected sooty mangabeys (Bosinger et al., 2009). Both are free access articles in pdf.

And finally, Scent Signals Stop Incest In Lemurs. Chemical identifiers secreted from genital glands by both males and females ring-tailed lemurs (Lemur catta) allow them to avoid incest and engage in nepotism. Decoding an olfactory mechanism of kin recognition and inbreeding avoidance in a primate (Boulet et al., 2009).

AAA's Student (Or Lack Thereof) Saturday

I was planning on tweeting about Student Saturday yesterday but I've decided against it, not because I was lazy, but I was generally underwhelmed by it. Fully acknowledging that this is the first Student Saturday organized by AAA, I still think that they should have planned a session where all the students can mingle (with a cash bar of course). For a first timer like me, it seems that the convention has too much going on at one time but I soon realized I should have dropped by the day before to pick up the itinerary and plan my day. By the time I walked in to the convention, I had missed both sessions (one about how to sell yourself with your CV and one about getting published) that actually made me want to go to Student Saturday. Bummer!

The graduate school fair was lack luster but this is also due to the fact that my interest lies in primatology, not the other "prominent" anthropology fields that AAA seems to represent. Most of the graduate schools that are present did not have any primatology program or their primatologists are not at the convention. But still, an opportunity to network is still an opportunity to network. Next to the graduate school fair was the book fair, which was more exciting for me to peruse. Surprisingly enough, I manage to find a book about Bigfoot! I also met a nice older lady who was wo-manning the "Gerontology" table (sorry I forgot your name!). We strike up a conversation about gerontology in primates and I told her about the newly published paper by Nakamichi, et al. (2009), which I also blogged last week. I realized that of all the people I spoke with at the convention, she was the only person I had an interesting conversation with.

All in all, Student Saturday was just another day at the AAA convention where they let us, lowly students, pay a small fee to join the festivities and mingle with the anthropological gods. I wish that they had planned sessions specifically for students or at least a reception or a meet-and-greet. Although to their credits, the itinerary does indicate sessions that might be interesting for students. But seriously, where are all the students? Maybe it's just that this is our first time at the convention and once we get a flow of it, things will be much more interesting. Maybe.

Philadelphia's Baby Sumatran Orangutan Gets A Name!

After two months of being born, the female baby Sumatran orangutan from Philadelphia Zoo finally gets a name! The baby is given the name Batu, named after a group of islands of the coast of Sumatra. The other two choices were Kadoa (small gift) and Anoano (blessing). Over half of the 3.400 online votes favor the name Batu, myself included. Batu was born in October 2nd, 2009 to father Sugi and mother Tua.

Batu, in the embrace of her mother Tua. Photo from Philadelphia Inquirer.

According to the Philadelphia Inquirer:

"PECO is sponsoring an Orangutan Baby Naming Weekend from 11 a.m. and 3 p.m. tomorrow and Sunday which will include special activities at the PECO Primate Reserve and giveaways to first 200 people to arrive at the zoo each day."

 So, go on down to Philadelphia Zoo and celebrate the merriment! Unfortunately I'll be at the American Anthropological Association (AAA)'s Student Saturday today and will be going to Mutter Museum with my friends on Sunday (though I might be able to persuade them to go to the zoo instead).

Read more about Batu: Baby Sumatran Orangutan Born In Philadelphia Zoo & Name The Female Baby Sumatran Orangutan.

American Anthropological Association (AAA): Student Saturday and Nonja, The Orangutan

Packing and getting ready for AAA's Student Saturday in Philadelphia this Saturday. Will blog about the event so stay tune!

Nonja and her camera.

In the mean time, I'm gonna leave you with Nonja, a female orangutan from Schönbrunn Zoo, Vienna. Nonja made headlines and became a sensation on Facebook for using a camera to take photo of herself and her enclosure. She probably doesn't know what a camera is but she knows that every snap of the camera dispenses a raisin as a treat. So you can say she's camera happy because she's raisin happy.

Nonja and her Facebook pose.

This is the "info" on Nonja's Facebook profile, in German.

"Nonja ist ein 33-jähriges Orang-Utan Weibchen. Die Fotos auf dieser Website sind von ihr fotografiert und zeigen das neue Gehege mit 750qm Freianlage im Tiergarten Schönbrunn. Die passende Kamera wurde von der Firma Samsung zur Verfügung gestellt."

"Nonja is a 33-year-old female orangutan. The photos on this website are photographs taken by her and shows the new enclosure with 750qm open area in the Schönbrunn Zoo. The camera was provided by the company Samsung."

Read the full story from Reuters here. Also, check out Nonja's Facebook profile!

Humans Were Born With The Urge To Help

The New York Times Science section has an interesting article about humans and their proneness to help each other, "We May Be Born With an Urge to Help".

Their [biologists] conclusions are derived in part from testing very young children, and partly from comparing human children with those of chimpanzees, hoping that the differences will point to what is distinctively human. The somewhat surprising answer at which some biologists have arrived is that babies are innately sociable and helpful to others. Of course every animal must to some extent be selfish to survive. But the biologists also see in humans a natural willingness to help ... “That’s why we have moral dilemmas,” Dr. Tomasello said, “because we are both selfish and altruistic at the same time.”

Read more about the news article, here.

New Exhibit At Warsaw Zoo, Poland: Cavemen!

Visitors at Warsaw Zoo in Poland are being reminded this week that humans are animals too when they walk past the "cavemen" exhibit. Two volunteers, a 24 year-old man and 18 year-old woman, dressed themselves in animal hide behind an old monkey cage. The exhibit runs till this Sunday.

Two volunteers in a former monkey cage and dressed as cavemen, are photographed by a visitor at the zoo in Warsaw, Poland, Friday, Nov. 27, 2009. The zoo has opened a week-long display where two volunteers - a man and a woman - spend time in the cage to remind visitors that humans are animals too. (AP Photo/Alik Keplicz)

"Organizer Maria Mastalerz says the weeklong "performance" aims to attract interest in a play, "Caveman," showing in the Polish capital. But she says it also carries a message that humans today are not all that different from their prehistoric ancestors" - Associated Press.

"They are very calm and gentle. They don't bite. And they're keen to watch all the strangers passing by their home. You can try to communicate with them, or even offer them food ... a playful attempt to inspire people to think about the place of humans in the universe", said the zoo's deputy director Ewa Zbornikowska, AFP.

Happy Thanksgiving, Y'all

This year, The Prancing Papio is thankful for the continuing support of its readers and friends. Without you, I will be just ranting and writing into the void. I'm also thankful to Kambiz from Primatology.net and Anthropology.net for inviting me to contribute to his blogs. This year is The Prancing Papio's first Thanksgiving. What are you thankful for this Thanksgiving?

I'd like to share some interesting anthropological articles about Thanksgiving. "Rethinking Thanksgiving",  by Vera L. Stenhouse is an interesting article about the myths and misgivings of Thanksgiving (Thanks Monkey Tales!) Also, an interview with Dr. Deborah Gewertz from Amherst College, "Who Knows: Deborah Gewertz, G. Henry Whitcomb 1874 Professor of Anthropology, on Thanksgiving". Thanksgiving is just not Thanksgiving without blaming the turkey for making you sleepy. "Thanksgiving Myth: Turkey Makes You Sleepy" from Live Science.

Hope y'all have a wonderful and tasty Thanksgiving!

Grandmothers Taking Care Of Their Granddaughters: Japanese Macaques

Japanese researchers observed two separate cases of grandmothers taking care of their granddaughters. The catch is, these grandmothers are free-ranging Japanese macaques (Macaca fuscata) and the researchers think that this is the first observed behavior in nonhuman primates that would support the "Grandmother Hypothesis". The Grandmother Hypothesis posits that female's post reproductive lifespan is reflected by the reproductive success of her offspring and the survival of her grandchildren.

According to the paper published on Primates, Nakamichi et al  (2009) observed that these grandmothers, without dependent offspring, were observed taking care of their granddaughters and even suckling them. The first case was a 24 year-old grandmother who provided essential care to her 2 month-old granddaughter after her mother temporarily disappeared from the group (the author cited unknown reason for her disappearance). The second case was a 23 year-old grandmother who suckled her 14 month-old granddaughter after her mother gave birth to a younger sibling. In summary, these behavioral data indicate that healthy grandmothers without dependent offspring could contribute to the survival of their grandchildren thus supporting the Grandmother Hypothesis.

The grandmother (GM1) is retrieving her granddaughter (GD1) (a), and GD1 is holding GM1’s nipple in her mouth (b) during the period of the mother’s (M1) temporary disappearance (21 July 2008). GM1 is grooming M1 who is nursing GD1 on the first day when M1 returned to the group (28 July 2008) (c). Photo from Nakamichi et al. (2009)

Read more about the article, Old grandmothers provide essential care to their young granddaughters in a free-ranging group of Japanese monkeys (Macaca fuscata) on Primates. Also, BBC ran a story about this article, Grandmother monkeys care for baby.

"To our knowledge, there have been no reported cases in which, instead of a mother, a grandmother without dependant offspring has continuously provided essential care for the survival of her dependant grandchild, which is in accordance with the grandmother hypothesis," Dr Nakamichi and colleagues write in the journal Primates. BBC Earth News, 2009.

References:

Nakamichi, M. Onishi, K. Yamada, K. 2009. Old grandmothers provide essential care to their young granddaughters in a free-ranging group of Japanese monkeys (Macaca fuscata). Primates Retrieved November 24, 2009, from http://www.springerlink.com/content/a30977860p50wt76/ doi: 10.1007/s10329-009-0177-7.

Walker, M. 2009. Grandmother monkeys care for baby. BBC Earth News Retrieved November 24, 2009, from http://news.bbc.co.uk/earth/hi/earth_news/newsid_8370000/8370743.stm.

Charles Darwin: On the Origin of Species. 150th Anniversary.

 Charles Darwin, circa 1854.

This year marks the 200th anniversary of Charles Darwin's birth (12th February, 1809) and tomorrow marks the 150th anniversary of Darwin's publication of On the Origin of Species (24th December, 1859). Have you thought of joining The Friends of Charles Darwin?

Did you know:

• Darwin's theory of evolution was influenced by the famous geologist Charles Lyell.
• While working in Malaysia, Alfred Russell Wallace came up with a theory of evolution similar to those of Charles Darwin. This made Darwin hurriedly published his works so Wallace do not get the credit as the first to introduce the theory. They later had a joint publication at the Linnean Society of London, giving each other credit for the idea.
  
• Scientists found newly evolved finch on the Galapagos Islands in 2009. Evolution caught in the act? Newly evolved finch appears on the Galapagos Islands!

This image, titled 'Man is But a Worm,' and published shortly before his death by Punch magazine, shows the great naturalist seated on God's throne, overseeing the evolution of an English gentleman out of 'chaos.' In 1881, Darwin had published an influential book on the ecology of earthworms. Photo from Tulane University.

What will you be doing tomorrow to commemorate Charles Darwin's 150th anniversary of the publication of  On the Origin of Species?

Hobbits Are Indeed A Separate Species, Said Researchers.

 Researchers from Stony Brook University Medical Center in New York confirmed that the Hobbits, or Homo floresiensis, are indeed a separate "human" species instead of a population of diseases Homo sapiens. The 7th Human Evolution Symposium, Hobbits in the Haystack: Homo floresiensis and Human Evolution was held this year at Stony Brook.

A recent full-body reconstruction of LB1, the ‘little lady of Flores’, by the Parisian paleoartist Elisabeth Daynès. (©2009, S. Plailly/E. Daynès—Reconstruction Atelier Daynès Paris). Photo from The geometry of hobbits: Homo floresiensis and human evolution.

Cranial comparison between LB1 (Homo floresiensis) and modern human. Photo from www.bbc.co.uk

Height comparison between modern humans and Homo floresiensis. Illustration from www.amnh.org

According to the press release, researchers William Jungers and Karen Baab used statistical analysis on the skeletal remains of LB1 (nicknamed Flo) to determine that Homo floresiensis are indeed a distinct species. A few characteristics of LB1 that makes her and her kind a separate species than modern humans.

• LB1's cranial capacity is about 400cc, about the same size as a chimpanzee.
• The skull and jawbone of LB1 is more primitive looking than any normal modern humans.
• The thigh bone and shin bone of LB1are much shorter compared to modern humans including Central African pygmies, South African KhoeSan (formerly known as 'bushmen") and "negrito" pygmies from the Andaman Islands and the Philippines. Jungers and Baab believe that these are primitive retentions as opposed to island dwarfing.
• Using a regression equation developed by Jungers, LB1 was about 3 feet, 6 inches (106cm) tall, far smaller than modern human pygmies whose adults grow to less than 4 feet, 11 inches (150cm) tall.

The nearly complete left foot of LB1 next to the right tibia (shin bone, which is ~235 mm long). The foot is relatively very long and has unusual intrinsic proportions; its footprint matches no other species (photo: W. Jungers) The geometry of hobbits: Homo floresiensis and human evolution.

Read more about the Hobbits at The geometry of hobbits: Homo floresiensis and human evolution (Free Wiley Interscience PDF).

Functions of Male Primate Coloration

Over at Beast Ape and The Bleeding Heart Baboons, Beast Ape posted an interesting blog about the functions of primate coloration as "badge of status" in males to indicate rank or status to other males or to convey information to females about the male's fitness or quality (think the peacock's train).

Name The Female Baby Sumatran Orangutan!

The Philadelphia Zoo's Sumatran orangutans, Tua and Sugi, welcomed their first baby last month. I've blogged about the announcement and press release here at Prancing Papio.

 Tua and her baby. Photo from Philadelphia Zoo.

Now the Philadelphia Zoo is giving you an opportunity to name this female orangutan baby by voting on the names available on the zoo's website. Personally, I'm partial to the name "Batu" because it's cute. Also because both her parent's names are two syllable as well. The baby orangutan debuts with her mother to the public on Thursday, Nov 12th. Click here for more photos of Tua and her baby from 6ABC.

A closeup photo of Tua and her baby. Photo from 6ABC.

The Kipunji Might Have Interbred With Baboons

The kipunji (Rungwecebus kipunji) was first known to science in 2003 when it was found dead in a farmer's trap near the forest of Mount Rungwe in Tanzania. Kipunji is geographically restricted to two small populations, Tanzania's Southern Highlands and Udzungwas Mountains. These endangered forest-dwelling monkeys have a very interesting history in their genetic makeup.

The kipunji. Photo from National Geographic by Tim Davenport.

Using fecal sample from Udzungwas Mountains (the Ndundulu population) and two tissue sample from Southern Highlands population, researchers from the National Evolutionary Synthesis Center (NESCent) were able to reconstruct the genetic relationships between these two populations and the kipunji's closest relative (Roberts et al., 2009). They found that the Ndundulu population retains the true Rungwecebus mitochondrial genome while the Southern Highlands population has a distinct mitochondrial haplotype that are basal to the genus Papio and Rungwecebus. This suggests that the Southern Highlands population is a hybrid and might have interbred with baboons while the Ndundulu population did not. The study also suggests that Rungwecebus is a separate genus and is more closely related to Papio than to Lophocebus, Theropithecus, Cercocebus or Mandrillus.

Census shows that there are about 1,100 individuals left in the wild. Of these, only 100 of them lives in Udzungwas Mountains. Losing the population from Udzungwas Mountains means that we will lose the genetic makeup of a true Rungwecebus.

Read more on National Geographic "Africa's rarest monkey may have bred with baboons".

References:

Davenport, TRB. Stanley, WT. Sargis, EJ. De Luca, DW. Mpunga, NE. Machaga, SJ. Olson, LE. 2006. A New Genus of African Monkey, Rungwecebus: Morphology, Ecology, and Molecular Phylogenetic. Science 312(5778) 1378 - 1381 DOI: 10.1126/science.1125631

Roberts, TE. Davenport, TRB. Hildebrandt, KBP. Jones, J. Stanley, WT. Sargis, EJ. Olson, LE. 2009. The biogeography of introgression in the critically endangered African monkey Rungwecebus kipunji. Biology Letters Retrieved November 12, 2009, from http://rsbl.royalsocietypublishing.org/content/early/2009/10/29/rsbl.2009.0741.abstract?papetoc

Contagious Yawning in Geladas

Over at Beast Ape & The Bleeding Heart Baboons blog, Beast Ape discusses about contagious yawning in geladas.

This research suggests that the yawning contagion is associated with the ability to attribute mental states to others (and possibly empathy). Among non-human mammals, contagious yawning has been demonstrated in chimpanzees (Pan troglodytes), stump-tailed macaques (Macaca arctoides), and domestic dogs (Canis familiaris).

Read more about that blog post here.

Photo of the day: Prospect Park's Hamadryas baboons

November's unpredictable weather always make me sick, plus the stress from studying for GRE this year is not helping either. Don't really have time to do another blog post until Sunday so I figure I'll share with you a photo of me and Pam, one of the female hamadryas baboons from The Prospect Park Zoo. She usually sits on the ledge, pressed next to the display glass, when I do my observation there. Sometimes she would actually sit behind me to hide from rowdy zoo patrons (you know, the ones that like to bang on the glass to agitate them). Or maybe she's just trying to hide from me, heh. Pam's actual name is Kobo (according to the zoo) but I gave these hamadryas a different set of names for easy identification.

Anyways, if you ever visit The Prospect Park Zoo, Pam is the female hamadryas baboon with a very short tail. Don't forget to say hi to her but PLEASE don't bang on the glass ... she hates it.

Pam looking at me, lamenting about rowdy zoo patrons.

Homosexuality: Was Darwin Wrong On Sexual Selection?

The article "The effeminate sheep and other problems with Darwinian sexual selection" by Jonah Lehrer was published in the June/July 2006 issue of SEED magazine. It's been circulating around the internet this past week after news broke that a high school teacher from Piasa, Illinois was suspended for giving his students this article to read as an optional class discussion. Soon, a Facebook group was created by students from Southwestern High School in support of their beloved teacher, Dan DeLong. The author of the article, Jonah Lehrer, also showed his support on his blog The Frontal Cortex. DeLong had since been given his job back after he publicly apologize for handing out an age inappropriate article. This whole outburst just screams homophobia to me. It is a disgrace to the country's education system because a thought provoking and queer-friendly curriculum resulted in someone being suspended. I bet none of the parents would even complain if their kids were given an article explaining the extinction of dinosaurs were due to them being late to Noah's ark.

Dinosaurs, Left Behind. Illustration from CartoonStock.

Anyway, back to the article. Joan Roughgarden, a Biology professor from Stanford University thinks that Darwin got it wrong about sexual selection. She also thinks that sexual theory is still stuck in the 19th century.

 Joan Roughgarden's book Evolution's Rainbow.

Two female bonobos having sex. Bonobos are fully bisexual, they don't really care which gender they are having sex with.

Sexual selection cannot explain homosexuality in over 450 different vertebrate species, said Roughgarden. Homosexuality, long thought to be deviant and serves no purpose biologically, is actually normal and a necessary fact of life.. Her book, Evolution's Rainbow, is an attack on Darwin's theory of sexual selection citing that the pervasiveness of homosexuality in the animal kingdom is actually adaptive and had not been weeded out by natural selection. She also said that homosexuality is a necessary side effect for getting along: a necessary feature of advanced animal communities that require communal bonds to function.

 Gay mallards Anas platyrhynchos. Photo from Wikipedia.

An example of this in the primate societies are the Japanese macaques (Macaca fuscata).

Japanese macaques, an old world primate, illustrate this principle perfectly. Macaque society revolves around females, who form intricate dominance hierarchies within a given group. Males are transient. To help maintain the necessary social networks, female macaques engage in rampant lesbianism. These friendly copulations, which can last up to four days, form the bedrock of macaque society, preventing unnecessary violence and aggression. Females that sleep together will even defend each other from the unwanted advances of male macaques. In fact, behavioral scientist Paul Vasey has found that females will choose to mate with another female, as opposed to a horny male, 92.5% of the time. While this lesbianism probably decreases reproductive success for macaques in the short term, in the long run it is clearly beneficial for the species, since it fosters social stability. “Same-sex sexuality is just another way of maintaining physical intimacy,” Roughgarden says. “It’s like grooming, except we have lots of pleasure neurons in our genitals. When animals exhibit homosexual behavior, they are just using their genitals for a socially significant purpose.”

Read more about Jonah Lehrer's "The effeminate sheep and other problems with Darwinian sexual selection" here.

"And Tango Makes Three". A storybook based on the real story of Silo and Roy, two gay chinstrap penguins from Central Park.

I think homosexuality in primates is an interesting yet often times a taboo topic. There should be more studies on the effect of homosexuality in primate societies. Are there differences and similarities between primate and human societies when it comes to homosexuality? I also think its about time to regard homosexuality as adaptive as opposed to maladaptive and start coming up with research to see how societies benefit from homosexuality. We already have the "Grandmother Hypothesis" so what about the "Gay, Lesbian and Transgender Family Member Hypothesis"?

Actor Rosario Dawson and her gay uncle, Frank. Poster from PFLAG.

What struck a cord for me was Roughgarden's explanation of homosexuality, “Same-sex sexuality is just another way of maintaining physical intimacy ... It’s like grooming, except we have lots of pleasure neurons in our genitals. When animals exhibit homosexual behavior, they are just using their genitals for a socially significant purpose".

Reference:

Lehrer, J. 2006. The effeminate sheep and other problems with Darwinian sexual selection. SEED Retrieved November 3, 2009, from http://seedmagazine.com/content/article/the_gay_animal_kingdom/

Behavioral Synchronization In Chacma Baboons

There is a newly published paper by Andrew J. King and Guy Cowlishaw on factors that promote or constrain group synchronization among Chacma baboons (Papio ursinus) in central Namibia. The paper "All together now: behavioural synchrony in baboons" is available online as pdf for free.

 A mother and infant Chacma baboon (Papio ursinus). Flickr photo from Arno & Louise.

Synchronized behavior is defined as behavior performed by individuals in unison. For example, you can say that a group of animals moving through its environment is synchronized in the direction of the movement. Or a group of animals feeding is synchronized in its behavior. Synchronized behavior has its costs and benefits. Group synchronization is costly to achieve, and according to this article, due to age - sex differences, morphological - physiological differences, heterogeneous feeding terrain and visual isolation between group members. The benefit of group synchronization increases foraging benefits and reduces predation risk. A large group who travels together can easily find food or spot predators.

An example of synchronized behavior. A group of baboons traveling in a synchronized direction in Tanzania. Photo from Hole In The Donut Travels.

Interestingly, this research found that the probability of the group to synchronize increases with the number of pregnant females in the group but decreases with the number of sexually swollen females in the group. They think that females that are sexually swollen are not shy about advertising their receptivity to the males in the group. The males, in turn, would zealously guard these sexually swollen females from other males thus disrupting behavioral synchronization. Pregnant females, on the other hand, promotes group synchronization because individuals are not fighting or distracted by mating opportunities.

Read more from the press release, Brazen Baboons: Flighty Females Disrupt Group Harmony.

References:
King, AJ. Cowlishaw, G. 2009. All together now: behavioural synchrony in baboons. Elsevier Retrieved October 31, 2009, from http://static.zsl.org/files/king-cowlishaw-animal-behaviour-2009-910.pdf

PR.com. 2009. Brazen Baboons: Flighty Females Disrupt Group Harmony. Retrieved October 31, 2009, from http://www.pr.com/press-release/188486

Chimps Mourn The Death Of Their Own

A picture is worth a thousand words. So, I'm gonna just let the photo do most of the talking. Ever since this photo was published it has gone viral everywhere. Read about this news story at National Geographic and an in depth explanation of the photo here.

This photo is not surprising because it is well documented that chimpanzees mourn the death of their own. I guess the reason why it went viral is because the sheer volume of individuals mourning the death of this female chimpanzee. It looks almost human-like and behaviors that are human-like tend to evoke empathy in humans.

Effects Of Global Warming On Endangered Primate Species

A study was done by Penn State Graduate students Ruscena Wiederholt and Biology professor Eric Post on how the effects of global warming, such as El Niño and El Niña, on endangered primate species. Focusing on New World Monkeys, Wiederholt and Post studied the trend of abundance and population dynamics in four genera of Atelines: the muriqui (Brachyteles hypoxanthus, formerly B. arachnoides) of Brazil, the woolly monkey (Lagothrix lagotricha) in Colombia, Geoffroy's spider monkey (Ateles geoffroyi) of Barro Colorado Island in Panama, and the red howler monkey (Alouatta seniculus) in Venezuela.

The results of the team's analyses were spectacular. All four monkey species showed drops in abundance relating to large-scale climate fluctuations. Even though the monkey populations were separated by large distances, the three fruit-eating species had synchronous responses to large-scale warming. During El Niño warming events, trees produced more fruit than usual. Then, during the subsequent La Niña cooling events, the trees produced much less fruit, resulting in a local scarcity or even famine.


Some ecologists have speculated that high production of fruit during El Niño events may have been triggered by the increase in solar radiation, despite lower-than-usual rainfall. However, high productivity during an El Niño event might also use up the stored reserves of the trees, which would have difficulty recovering during the subsequent La Niña events, when weather was wet, cloudy, and cool. This mechanism would explain why the fruit-eating monkeys showed a delayed response to the El Niño events after a lag of one or two years.

Howler monkeys also showed declines with warm and dry El Niño events, but their population fall was out of sync with that of the fruit-eating species. The mechanism is not yet clear, but Wiederholt has some ideas. She notes, "Primate researchers have seen elevated adult female mortality and lowered birthrates among red howlers in drought years. Since leaf flush often occurs at the start of the wet season, a prolonged dry season might delay the availability of this resource for the howlers and perhaps cause them nutritional stress."


Warmer temperatures also may cause leaves -- the howlers' primary food -- to mature faster, which would accelerate the leaves' acquisition of toxins and other chemical defenses against monkeys. The factor that the scientists found was most influenced by changes in climate was the monthly maximum number of tree species that were fruiting. Climate changes also were highly correlated with the monthly maximum number of species that were flowering and with annual seed production. The length of the dry season also was highly correlated with annual flower production. Thus, vegetation responses to climatic conditions substantially altered the food resources available to primates, which in turn influenced the decline or rise in monkey abundance.

Read the rest of the article from EurekAlert!

Modern Humans Are Still Evolving But Will Modern Men Get Wimpier?

Two interesting articles that went into my inbox today: Modern man a wimp says anthropologist and Darwin Lives! Modern Humans Are Still Evolving.

A cover illustration from Australian anthropologist Peter McAllister's new book entitled "Manthropology" and sub-titled "The Science of the Inadequate Modern Male." Photo from REUTERS/Hachette Publishing/Handout.

Modern man a wimp says anthropologist  from Reuters, summarizes Peter McAllister's book Manthropology: The Science of the Inadequate Modern Male. Using various data from Neanderthals and ancient aboriginal populations, McAllister concludes that modern men are inferior than their predecessor in running, jumping, and even sheer brute. "Any Neanderthal woman could have beaten former bodybuilder and current California governor Arnold Schwarzenegger in an arm wrestle", McAllister said. John Hawks from John Hawks Weblog has a lot to say about this in his post Is modern man a "wimp"? I think Hawks is spot on with his post.

The Time article, Darwin Lives! Modern Humans Are Still Evolving, is about a study in a contemporary Massachusetts population led by Stephen Stearns and his team of scientists from Yale University. Using correlations between women's physical characteristics such as height, weight, blood pressure, and cholesterol levels with the numbers of offspring produced, they found that "stout, slightly plump, but not obese" women tend to have more offspring as oppose to women with very low body fat count, as well as women with lower blood pressure and lower cholesterol levels.

Stearns explains that women with very low body fat count, low blood pressure and low cholesterol levels do not ovulate. Ovulation is, of course, when the matured ovarian follicle ruptures and discharge an ovum (or the egg). While human females ovulate about once a month, female chickens ovulate once a day. Of course, we refer to chicken ovum as chicken eggs.

Stearns and his team thinks that the characteristics for producing maximum offspring (stout, slightly plump, higher blood pressure and cholesterol levels) were passed down from mothers to daughters. Separating social and cultural factors using statistical analysis, Stearns and his team were able to conclude that these characteristics were passed down genetically. "Variations in reproductive success still exist among humans, and therefore some traits related to fertility continue to be shaped by natural selection" Stearns says. So women who have more children are more likely to pass down these traits to their offspring.

It explains the notion that modern humans are still evolving because variation in reproductive success means that there are selective pressure that favor certain traits. Interesting to note that while fertility is being shaped by natural selection (as per Stearn and his team's study), artificial selection is also shaping the width of female pelvis and the average brain size of infants being born. Mothers with a narrow birth canal (smaller pelvis size) puts both her and her infant in jeopardy during childbirth. The infant will be stuck in the birth canal due to restricted space. An infant with a larger than average brain size will also get stuck in the birth canal. Both scenarios will likely kill the infant and mother. However the advent of Caesarean section negates the restriction of a narrow birth canal and allows infant with larger brain size to be born.

So, we can see that modern humans are evolving through variation in reproductive success, female pelvis size and average infant brain size is also evolving through artificial selection though it is too early to say which direction the selection is favoring.

When It Comes To Being The "Missing Link", Ida -- You Are NOT The Candidate

Main slab of Darwinius masillae (specimen PMO 214.214), new genus and species, from Messel in Germany. Photo from Wikipedia.

Ida or "Aunt Ida" as many might recall from this summer of craziness sent shock waves around the nation as it was herald the missing link between prosimians and anthropoids (primates and human). Deserving of its own genus, Ida was given the name Darwinius masillae by Franzen et al. (2009) as they describe this specimen in their paper. Darwinius to celebrate the bicentennial celebration of Darwin's claim to fame "Origin of Species" and masillae for the location where Ida was discovered (Messel Pit, Germany).


Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology was published this summer. Soon thereafter, the general public expressed sheer amazement and curiosity, especially the press who were all too excited to report such breaking news. Hence, "Aunt Ida" became synonymous with "Ida" due to the general public's warm family reception. Others, such as the religious nuts were quick to point out that Ida was just another god(s) creation and the notion of a "missing link" is preposterous. Even Google participated in this frenzy, much to the chagrin of religious right-wing, featuring Ida in Google's logo on May 20th, 2009.

Ida as Google icon. Illustration from Google.

American Museum of Natural History soon announced that you can see Darwinius masillae in their Extreme Mammal exhibit (which I later find out that it is just a cast). The Discovery Center at Times Square also got into the game by exhibiting Darwinius masillae. All these publicity and attention makes one wonder. Is this just a publicity stunt on a premature discovery and discussion? Not to mention all the money they made from this discovery "that changes everything".

I, for one, was on the fence. While I was amazed and interested with the discovery, all these publicity stunt just does not bode well with me. I chose not to write about Ida's discovery in this blog, not because I was too lazy to add my one cent but rather I'd prefer to sit back and listen to all the discussions. One, I'm not a paleontologist nor am I an expert on skeletal morphology. I'd love to know if  Darwinius masillae actually groomed each other though.

So what made me wrote this blog entry? My inbox is filled with new articles about Darwinius masillae but this time disproving its role as the missing link. A new paper, published by Seiffert et al. (2009), concludes that Darwinius masillae is closely related to the genus Afradapis (an adapiform or adapoid). They also conclude that Darwinius masillae sits on the dead end of the evolutionary branch, without leaving any descendants let alone being the missing link for humans. Thus the title "missing link" is not befitting of this 47 million year old Eocene primate.

Phylogenetic position of the adapiforms Afradapis and Darwinius within primates. Photo from Wired.

So now that you have both sides of the story, what's your opinion on  Darwinius masillae? I'm betting my bananas that Darwinius masillae is just another product of a highly publicized discovery. Not to undermine the important discovery of this new genus but quoting my undergraduate professor, Dr. Sara Stinson, "There is no such thing as a missing link. We know where everything goes". She's right ... in fact the idea of a "missing link" is just an agent used by those who do not believe in evolution. You know, like the idea of Crocoduck (Hint: Kirk Cameron).

Further readings:
Bone Crunching Debunks ‘First Monkey’ Ida Fossil Hype from Wired.
So Ida's not the "missing link": questions and answers with Erik Seiffert from Times Online.
'Eighth wonder' Ida is not related to humans, claim scientists from Guardian.co.uk.
Darwinius on Wikipedia.

References:
Franzen, JL. Gingerich PD. Habersetzer, J. Hurum, JH. von Koenigswald, W. Smith, BH. 2009. Complete Primate Skeleton from the Middle Eocene of Messel in Germany: Morphology and Paleobiology. PLos ONE 4(5): doi:10.1371/journal.pone.0005723.

Seiffert, ER. Perry, JMG. Simons, EL. Boyer, DM. 2009. Convergent evolution of anthropoid-like adaptations in Eocene adapiform primates. Nature 461, 1118-1121 doi:10.1038/nature08429.

Chimpanzees: Ask And You Shall Receive

A new study published by Shinya Yamamoto, Tatyana Humle and Masayuki Tanaka on PLoS ONE found that chimpanzees willing to help one another. All they have to do is ask.

Ask and you shall receive. Video from NewScientist.

Using two tool-use scenarios (a stick tool-use and a straw tool-use), both chimpanzees were placed in adjacent booths with non-corresponding tools. The chimpanzee in a stick tool-use scenario was given a straw while the chimpanzee in a straw tool-use was given a stick. Successful use of tool resulted in a reward, a carton of juice. A spontaneous tool transfer was observed between paired chimpanzees, mostly following the request of the recipient. Even though reciprocity was not always observed, the chimpanzees continue to assist their partners as long as their partner requested help.

The authors argues that these results further prove the evidence for altruistic behavior in chimpanzees without direct personal gain or immediate reciprocation. These results also highlight the importance of "request" as a cause for prosocial behavior in chimpanzees, between kins or non-kins and also interaction between dominant and non-dominant individuals.

When compared to humans, chimpanzees do not perform acts of voluntary altruism. Unlike humans,  chimpanzees do not necessarily act altruistically by just observing another chimpanzee struggle to achieve its goal. Chimpanzees cannot accurately understand others' desires in the absence of communicative signals such as a request.

Further reading on NewScientist.

Reference:
Yamamoto, S. Humle, T. Masayuki, T. 2009. Chimpanzees Help Each Other upon Request. PLoS ONE 4(10): e7416. [doi:10.1371/journal.pone.0007416]

The Uncanny Valley: Humans and Macaques

The uncanny valley hypothesis posits that when robots and other human facsimiles look and act almost like humans, it causes a response of revulsion among human observers. The "uncanny valley" refers to the dip in the graph of the positivity of human reaction as a function of a robot and other human facsimiles's life-likeness (see below).

Hypothesized emotional response of human subjects is plotted against anthropomorphism of a robot, following Mori's statements. The uncanny valley is the region of negative emotional response towards robots that seem "almost human". Movement amplifies the emotional response. Photo from Wikipedia.

It is the reason why we prefer cartoon characters than CGI characters that look realistic. For example, you are more likely to like the Homer Simpson on the left than the one on the right.

Read about the uncanny valley hypothesis here.

Now this is the interesting part. Using long-tailed macaques (Macaca fascicularis) as test subjects, Steckenfinger and Ghazanfar (2009) found that these monkeys' visual behavior actually fell into the uncanny valley, which mirrors the behavior of humans. These macaques looked longer at real faces and unrealistic synthetic faces than realistic synthetic faces.

The unrealistic synthetic faces, realistic synthetic faces and real faces. Actual images used in Steckenfinger and Ghazanfar's experiment.

The authors did not conclude why the visual cues of these macaques fall into the uncanny valley, though they did suggest that it has an evolutionary basis.

Remember the picture above? If not, read my blog entry on Contagious Yawning in Chimpanzees. I see you yawn. I wonder if those chimpanzees will yawn if given more realistic synthetic faces.

Reference:
Steckenfinger, SA. Ghazanfar, AA. 2009. Monkey Visual Behaviors Falls Into The Uncanny Valley. Proceedings of the National Academy of Sciences Retrieved October 15, 2009, from http://www.pnas.org/content/early/2009/10/07/0910063106.full.pdf+html [10.1073/pnas.091006310]