Handedness in Humans and Geladas

I thought I’d share a paper I wrote from last semester’s Comparative Psychology class on handedness in humans and geladas. Debating if I should actually follow through with this preliminary report and do some data collection. There is a YouTube video that accompanies this paper, which will appear on the bottom of the page.

Handedness can be defined as the unequal distribution of fine motor skills between the left and right hands. Simply put, handedness is the preference to use left, right or both hands when performing tasks. Humans are mostly right-handed across cultures. Here, I compare handedness in humans (Homo sapiens) to handedness in geladas (Theropithecus gelada).

Right-handedness is predominant across cultures in humans. About 85% to 90% of humans report themselves as right-handers (10). In studies of great apes, comparative analysis indicates that chimpanzees and bonobos exhibit population-level preference in right-handedness while gorillas and orangutans do not exhibit population-level preference in handedness (10). However, right-handedness seems to be uniquely human as no other primate species has such a clear bias (1, 13 & 14). The objective of this preliminary study is to elucidate whether geladas exhibit preference in handedness.

A male gelada at The Bronx Zoo.

Geladas are Old World Monkeys and can be found in the high plateau of North Central Ethiopia and Eritrea (9 & 2). Geladas are sometimes referred to as “bleeding heart monkeys” due to the presence of a naked, pink patch of skin on the chest of males and females that looks like an hourglass (2). They exhibit sexual dimorphism; males have manes and are slightly larger than females. The maximum lifespan of a gelada is about 19 years in the wild (5) and well over 30 years in captivity (9). Geladas are gramnivores; they are unique among primates because grass is their main food source but is occasionally supplemented by seeds, roots, and bulbs (3).

There are many definitions of handedness. Here, I define handedness as the preference of left, right or either hand when performing tasks. In humans, those who have a preference for using their right hand are right-handed while those that prefer using their left hand are left-handed. Those that prefer to use either hand when performing tasks are ambidextrous.

Approximate location of Broca's area and Wernicke's area. Photo from Wikipedia.

Handedness is due to the lateralization (asymmetry) of the brain hemispheres. Those that are right-handed have a more dominant left hemisphere, while those that are left-handed have a more dominant right hemisphere. In most humans, the left hemisphere of the brain is more dominant. The left brain hemisphere is also involved in language and is where Broca’s area and Wernicke’s area are located. Broca’s area is involved in speech production while Wernicke’s area is involved in language comprehension.

Right-handed preference is deep-seated in hominid evolution. Analysis of stone tools from Lower Pleistocene sites in Koobi Fora, Kenya and Middle Pleistocene sites in Ambrona, Spain showed that there is a consistent pattern of tools being produced by right-handed Homo habilis and Homo erectus (15). Preference for right-handedness may have existed as early as 1.4 to 1.9 million years ago, and might hint that the hominid brain had lateralized and was well on its way to becoming more specialized for different functions (15). Analysis of scratch patterns in incisors and canines from archaic humans (Sima de los Huesos in Atapuerca, Spain) and European Neandertals (Sima de los Huesos in Atapuerca, Spain and Vindija, Croatia) also showed that there was a persistent pattern of right handedness (6 & 7).

The prevalence of right-handedness in humans has a linear correlation with left hemisphere dominance (12). Since the left brain hemisphere plays an important role in language, brain lateralization leads to right-handedness. Thus, the prevalence of right-handedness in humans is a byproduct of human language.

The left-handed Ned Flanders from The Simpsons. Photo from SF Weekly.

The subjects for this study are from a captive population of geladas at The Bronx Zoo (Wildlife Conservation Society). There were 7 individuals present during the observations and all were male. Observations were done on two separate days between 12 P.M. and 3 P.M. The geladas were recorded using a video camera, and the recordings were later analyzed.

Geladas spend a significant amount of their time foraging (8). Site studies show that geladas spend 35.7% to 81.6% of their time foraging (8). There is a positive correlation between altitude and time spent foraging; more energy is burnt at higher altitudes, therefore more time is spent foraging (11).

A male gelada foraging with both hands.

My observations showed that geladas use either hand while foraging. They use either their left or right hands to pick up bunches of grass to eat. As my observation progressed, I became concerned that their repetitive motion of picking up grass and putting it in their mouths was not a sufficiently varied behavior to indicate handedness. Therefore, I also observed the geladas grooming.

A female gelada grooming herself.

There are two types of grooming in geladas: autogrooming (self grooming) and allogrooming (social grooming). Grooming is not only important for hygienic reasons but also important for strengthening social bonds (4). A study by Dunbar suggests that the major reason for grooming is the satisfaction of physical contact between the groomer and the individual being groomed (4).

From my observations, allogrooming starts with the individual being groomed initiating eye contact with the groomer. Then, the individual lies down and presents the area that needs to be groomed. Sometimes, a groomer simply approaches the individual they want to groom and starts grooming them. My observations showed that there is also no preference for which hand is used by geladas during grooming. The geladas used either hand for both autogrooming and allogrooming. The decision to use their left or right hand seemed to be determined by the area of the body that needed grooming.

From my observations, it seems that the geladas use either hand for foraging and grooming. The geladas at The Bronx Zoo seem to exhibit ambidexterity because they have no preference for their left or right hand, unlike humans who are predominantly right-handed.

Handedness is correlated with brain hemisphere dominance. For most humans, the left brain hemisphere is dominant and is also involved in language. Thus, the prevalence of right-handedness is a byproduct of human language. None of the geladas I observed at The Bronx Zoo exhibited preference for handedness. This is probably due to the fact that geladas do not have language; therefore, their left brain hemisphere is not dominant and does not lead to right-handedness. Besides foraging and grooming, more behavioral repertoire should be used in future analysis to further elucidate the preference in gelada handedness.









 References

 1. Cashmore, L., Uomini, N., & Chapelain, A. (2008). The evolution of handedness in humans and great apes. Journal of Anthropological Sciences, 86, 7-35.

 2. Dunbar, R.I.M., &; Dunbar, P. (1975). Contributions to Primatology: Social Dynamics of Gelada Baboons (Vol. 6). Basel, Switzerland: S. Karger AG.

 3. Dunbar, R.I.M. (1984). Reproductive Decisions. Princeton, New Jersey: Princeton University Press.

 4. Dunbar, R.I.M. (2008). The social role of touch in humans and primates: Behavioural function and neurobiological mechanisms. Neuroscience and Biobehavioral Reviews, 34(2), 260-268.

 5. Falk, D. (2000). Primate Diversity. New York and London: W.W. Norton & Company.

 6. Frayer, W.D., Fiore, I., Lalueza-Fox, C., Radovčić J., & Bondioli, L. (2010). Right handed Neandertals: Vindija and beyond. Journal of Anthropological Sciences, 88, 113-127.

 7. Frayer, W.D., Lozano, M., de Castro, J.M.B., Carbonell, E., Arsuaga, J.L., Radovčić J., Fiore, I., & Bondioli, L. (2011). Laterality: Asymmetries of Body, Brain and Cognition, doi:10.1080/1357650X.2010.529451

 8. Gron, KJ. (2008, September 3). Primate Factsheets: Gelada baboon (Theropithecus gelada) Taxonomy, Morphology, & Ecology. Retrieved May 11, 2011, from www.pin.primate.wisc.edu/factsheets/entry/gelada_baboon

 9. Hiller, C. (2000). "Theropithecus gelada" (On-line), Animal Diversity Web. Retrieved May 11, 2011, from www.animaldiversity.ummz.umich.edu/site/accounts/information/Theropithecus_ gelada.html

10. Hopkins, W.D. (2006). Comparative and Familial Analysis of Handedness in Great Apes. Psychology Bulletin, 132(4), 538–559.

 11. Iwamoto, T., & Dunbar, R.I.M. (1983). Thermoregulation, Habitat Quality and The Behavioural Ecology of Gelada Baboons. Journal of Animal Ecology, 52, 257-366.

12. Knecht, S., Dräger, B., Deppe, M., Bobe, L., Lohmann, H., Flöel, A., Ringelstein, E.-B., & Henningsen, H. (2000). Handedness and hemispheric language dominance in healthy humans. Brain, 123 (12), 2512-2518

13. McGrew, W.C., & Marchant, L.F. (1997). On the other hand: Current issues in and meta-analysis of the behavioral laterality of hand function in nonhuman primates. American Journal of Physical Anthropology, 104(25), 201-232.

 14. Steele, J. & Uomini, N. (2009). Can the Archaeology of Manual Specialization Tell Us Anything About Language Evolution? A Survey of the State of Play. Cambridge Archaeological Journal, 19, 97-110.

15. Toth, N. (1985). Archaeological Evidence for Preferential Right-Handedness in The Lower And Middle Pleistocene, and Its Possible Implications. Journal of Human Evolution, 14(6,) 607-614.

Apes Walking Upright: That's Just How They Roll (or Walk).

Orangutans, gorillas and chimpanzees do it. Bonobos seem to love doing it. Apparently gibbons do it really well. Indeed, bipedalism is not unique to humans and is quite common among apes. Apes are known to walk upright once in awhile, although bonobos seem to do it more frequently than other apes. Bipedalism is just one of the natural repertoire of ape locomotion.

(From left to right) Upright Apes Brigade: Gibbon, Orangutan, Gorilla, Chimpanzee and Bonobo. Click photo for larger image.

Upright Gorilla Goes Viral: 

Ambam the gorilla. Photo from Dailymail.

Currently going viral on the internet is a video of Ambam, a Western lowland gorilla (Gorilla gorilla gorilla) that was filmed walking upright in his enclosure. This 21 year-old, 485 lb. ape currently resides at Port Lympne wild animal park in Kent, England.

If you have not heard of Ambam or caught on to this internet sensation, you can read about him on :
Ambam, the swaggering silverback gorilla who walks around his pen on two legs (DailyMail)
Yes, he can walk. But just how close IS he to being human? (DailyMail)
Walk like a man: Gorilla strolls on hind legs (MSNBC).

It is not uncommon to see a gorilla walk upright but what's unique about Ambam is that he seems to walk upright quite frequently and good at it too. Bipedal locomotion is common in gorillas but they spend most of their time knuckle-walking. Ambam's upright gait and locomotion is definitely not an upright display to intimidate. Instead, it is most probably in response to curiosity and foraging in his enclosure. One of his keeper, Phil Ridges said:

"We think he might use it to get a height advantage to look over the wall when keepers come to feed him and standing up can also help him in looking for food generally in his enclosure as it gives him a better vantage point." Ridges added that Ambam could also carry more food if his hands were freed from walking and it also meant "he doesn't get his hands wet when it is raining."

It seems that the penchant for bipedalism runs deep in Ambam's family. His father, sister and half-sister (same father) prefer to walk upright and stand the same way as Ambam.

Ambam standing upright. Photo from Dailymail.

Is this a novel behavior in response to being in captivity? Is his skeletal and muscular structure (and in some sense his father, sister and half-sister) different than other gorillas? I think it would be interesting to see a behavioral study and an ethogram on Ambam's choice of locomotion. What are the percentage (or time spent) of him walking upright compared to knuckle-walking. Will his offspring be a fan of bipedality as well?

The Other Upright Ape:
While Ambam seem to prefer walking upright once in awhile, there is another ape that came before him who is a habitual biped. This ape is a chimpanzee named Oliver.

Oliver was a media (and science) sensation in the 60s and 70s for his preferred upright locomotion, having 47 chromosomes and a less prognathic face compared to other chimpanzees. Humans have 46 chromosomes while chimpanzees have 48 chromosomes. It was thought that Oliver is a "missing link" between chimpanzees and humans, thus nicknamed the "humanzee". While Oliver is not the missing link (Ely et al.,1998), he is truly a habitual biped.

The 52 year-old Oliver currently resides at Primarily Primates, a sanctuary in San Antonio, Texas. Below is a really good video of Oliver from his early years to his retirement. Seeing what happened to Oliver, I hope that they will not parade Ambam around like a freak of nature.

UPDATE: Oliver passed away on June 2nd 2012 at Primarily Primates. Read more here.

Reference:
Ely, J.J. Leland, M. Martino, M. Swett, W. Moore, C.M. 1998. Technical note: Chromosomal and mtDNA analysis of Oliver. American Journal of Physical Anthropology 105(3) 395-403. DOI: http://www3.interscience.wiley.com/journal/28165/abstract?CRETRY=1&SRETRY=0

Wordless Wednesday

Ape behavior inside the exhibit and holding area

An insightful paper published by Ross et al. (2010), compares zoo-living ape behavior inside their holding and exhibit areas in Lincoln Park Zoo, an accredited member of Association for Zoos and Aquarium (AZA). Zoo animals usually have at least two areas where they are housed (excluding some aquatic animals): the holding area and the exhibit area. During visiting hours and at night, zoo animals are housed in their exhibit area. In the morning, before the zoo opens, they move into the holding area to receive husbandry care and their morning food ration.

The gorilla exhibit area in Lincoln Park Zoo. Photo from Things You Should Do.

One of the chimpanzee from the study, Kipper (now deceased), from Lincoln Park Zoo interacting with a child. Photo by Chicago Tribute.

Holding and exhibit areas differ in size, design and functionality. A study by Ross and Lukas on 11 AZA-accredited zoos shows that holding areas are usually about 40 times smaller than exhibit areas (Ross et al., 2010). At the Lincoln Park Zoo, the holding area is about 9.3% of the size of the exhibit area (for both gorillas and chimpanzees). Whereas the exhibit area is designed for the complexity and to mimic the natural environment of its animal inhabitant, the holding area is usually designed for simplicity and functionality to meet husbandry needs.

Seven gorillas (2 males, 5 females; N = 7) and seven chimpanzees (3 males, 4 females; N = 7) were observed in this study. I should point out that the authors of the study is by no means criticizing Lincoln Park Zoo. It is an informal observation of behavioral changes for these animals in different environment. The result of the study shows that:

Gorillas
Inside the holding area - Increased locomotion and affiliative behavior. Also showed increased rates of aggression, self-directed behavior (subject touches, manipulates or examines the body, skin, or hair) and solitary play. Were in close proximity with each other.

Inside the exhibit area - Increased feeding and foraging behavior and also sexual behavior.

Chimpanzees
Inside the holding area - Increased aggression. Increased rate of scratching and self directed behavior (subject touches, manipulates or examines the body, skin, or hair). Were in close proximity with each other.

Inside the exhibit area - Increased feeding and foraging behavior.

Schematic representation of a typical holding area suite for an individual chimpanzee or gorilla social group at the Regenstein Center for African Apes. Shaded areas indicate animal enclosures; noncolored areas are sections of human activity (caretakers and data collectors). (Ross et al., 2010)

Both gorillas and chimpanzees showed increased aggression accompanied with self directed behavior when inside holding area. Increase in aggression can sometimes be attributed to overcrowding and self directed behavior generally means that an animal is nervous. Being constrained in a smaller space increases the chance of mixed-sex and mixed-dominance encounters thus resulting in agonistic and submissive observations. When inside exhibit areas, both apes exhibited an increase in feeding and foraging behavior. This presumably is due to their feeding and foraging habit in the exhibit area. If I remember correctly, one of the major breakthrough in exhibiting apes (and most animals) is to encourage foraging behavior throughout the day. It is no surprise that these apes exhibit these behaviors.

Chimpanzee subjects in a single enclosure in a holding area suite, during a period of free access (following training and research protocols). Photograph was taken from the central caretaker area. (Ross et al., 2010)

These apes reacted differently when inside their holding area than in their exhibit area because they are exposed to different sensory. Apart from the difference in size and complexity, these two areas also differ in the degree of human interaction, cross-species presence, environmental factors and time spent between these two areas. An understanding of these differences and motivational factors is important in promoting optimized environments for captive apes. The authors encourage that zoos would consider species-specific functional, physical and social preferences when designing enclosures for apes regardless of frequency of use.

Reference:
Ross, S. Wagner, K. Schapiro, S. Hau, J. 2010. Ape behavior in two alternating environments: comparing exhibit and short-term holding areas. American Journal of Primatology 72: 951–959. doi: 10.1002/ajp.20857

Wordless Wednesday

Life Is Good: Baby Gorilla Relaxing In Human-Like Pose

Yewande relaxing in human-like pose. Photo from Telegraph.

This photo was taken at Calgary Zoo, Canada by zoo visitor Nancy Chow. The baby lowland gorilla, a six month old female name Yewande, decided to "chillax" after playing with her favorite pink blanket. Struck by Yewande's pose, Chow took this picture. "When I took this shot I love it right away because the baby gorilla was so adorable, Yewande looks so human-like. It is easy to see how closely we are related to these great apes, Yewande's pose could be any one of us taking a well-earned break. Except I don't think I could do that with my feet", said Chow. Read more on Telegraph: Baby gorilla pictured 'relaxing' in human-like pose.

What a great photo. Thanks to my friend Kambiz for pointing it out that it's blog-worthy. This photo also reminds me of what Dr. Frans de Waal said, "Contrary to general belief, humans imitate apes more than the reverse". So, is this baby gorilla relaxing in human-like pose or are humans relaxing in ape-like pose?

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).

Contagious Yawning in Chimpanzees

Animation of chimpanzee yawning from Emory University. Illustration from BBC News.

I'm sure we are all familiar with this scenario: Someone yawns and we would "catch" it or vice versa. This is the phenomenon of contagious yawning.

A new paper from The Proceedings of The Royal Society "Computer animations stimulate contagious yawning in chimpanzees" suggests that the phenomenon of contagious yawning and empathic response to animation occurs in chimpanzees. Computer animations of yawning chimpanzees (see illustration above) can be use to stimulate contagious yawning in chimpanzees. Previous researches have documented contagious yawning in chimpanzees through video-recorded footage.

Dr. Matthew Campbell, lead author of the paper from Emory University's Yerkes National Primate Research Center said that they would also like to learn more about behaviors that are related to empathy such as consolation (when an individual does something nice to the victim of aggression). They want to know if individuals that are good contagious yawners are also good consolers. Understanding how chimpanzees empathize and imitate animations can help us understand how we, as human beings, empathize and imitate animations as well, said Dr. Campbell.

Humans Evolved From Tree Climbers

A research from Duke University by Daniel Schmitt, associate professor of evolutionary anthropology, and Tracy Kivell, a post-doctoral research associate, shows that human evolved from tree climbing ancestors, not from knuckle-walkers. Schmitt and Kivell examined and compared the wrist bones of humans and African apes. Their research, "Independent evolution of knuckle-walking in African apes shows that humans did not evolve from a knuckle-walking ancestor", was published in the Proceedings of the National Academy of Sciences on August 10th, 2009.

They also found that knuckle walking evolved at least two different times; gorillas fundamentally knuckle walk differently than chimpanzees and bonobos.

Kivell and Schmitt think this suggests independent evolution of knuckle-walking behavior in the two African ape lineages.

Some scientists point to features in the human anatomy as our own vestiges of a knuckle-walking ancestry. One notable example is the fusion a two wrist bones that could provide us extra stability, a feature we share with gorillas, chimps and bonobos.

But some lemurs have that feature too, and they do a variety of different movements in the trees but do not knuckle-walk, Kivell said.

Altogether, the evidence leans against the idea that our own bipedalism evolved from a knuckle-walking ancestor, the pair wrote. "Instead, our data support the opposite notion, that features of the hand and wrist found in the human fossil record that have traditionally been treated as indicators of knuckle-walking behavior in general are in fact evidence of arboreality."

In other words, a long-ago ancestor species that spent its time in the trees moved to the ground and began walking upright.

There are no fossils from the time of this transition, which likely occurred about seven million years ago, Kivell and Schmitt said. But none of the later fossils considered to be on the direct human line were knuckle-walkers.

Read more on Science Daily: Bipedal Humans Came Down From The Trees, Not Up From The Ground

Great Apes LOL Like Human Too

A baby orangutan being tickled. Photo from Discovery News.

We're not the only species that are capable of laughing according to new study. Great apes are able to laugh like humans too, and they do it frequenty. This finding suggests that the last common ancestor of humans and apes also laughed around 10 to 16 million years ago. The ability to laugh subsequently evolved among apes and human, resulting in distinctive ways of laughing among them.

"Orangutans produce a short laugh series of noisy calls. Gorillas, chimps and bonobos produce longer laugh series and the calls are produced more rapidly" said project leader Marina Davila Ross, a primatologist from University of Portsmouth. With partners Michael Owren and Elke Zimmermann, Davila Ross recorded over 800 recordings of 22 juvenile and infant apes, and also three human babies laughing as they were tickled in their palms, feet, necks and armpits.

Presented in the latest edition of Current Biology, the study shows that human laughter is most similar to that of chimpanzees and bonobos, followed by gorillas and orangutans. Human laughter is least similar to those of siamangs, a lesser ape. "These results coincide with the genetic topology of great apes and humans," said Davila Ross. She doesn't rule out if apes or monkeys have a sense of humor but said that "it is difficult to find a method to accurately test it".

Read the rest of the article from Discovery News: Chimps, Other Apes Laugh Like People.

I wonder what function does laughing serve in primates.

Orangutans Found Cannibalizing Own Babies

Sorry for not updating this blog for almost 2 weeks. I just finished my finals and I am currently busy finishing my thesis. Oh, I also graduate this Thursday!
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Reported in gorillas and documented in chimpanzees, some apes actually cannibalize their own species. However, there were reports of orangutans cannibalizing their own babies were reported in the same forest area of Indonesia, just one month apart from each other. This might be the first report of an ape eating its own offspring.

"Cannibalism has been documented in chimpanzees and reported in gorillas. Never before has any ape species been seen treating its own offspring as a consumable resource", said David Dellatore of Oxford Brookes University. Dellatore suspects that the mothers' stressed upbringing may have triggered their later actions.

Read the article from BBC - Earth News "Orangutans cannibalise own babies".

Female Orangutans Steal From Potential Mates

It seems that female orangutans steal from potential mates to test them, according to a new study. Females prefer males that do not fight back when they steal their food. This behavior evolved so that females can choose males that are not overly aggressive. Being aggressive towards other males to protect the females is a good thing. Males that are aggressive towards their females, however, is not. Male's aggression towards a female limits their choice to choose whom or when they mate, according to Maria van Noordwijk from the University of Zurich. So, when a female steals from her potential mate, it is an evolutionary adaption to test out their potential mate's aggression and tolerance towards her. Read the full article from National Geographic.

90% Of Wild Chimpanzees In Côte d'Ivoire Are Dead

A juvenile chimpanzee playing with a stick in Gdansk Zoo, Poland. Photo from Cellerimus.

Pretty grim statistics from Examiner.com. According to the Max Planck Institute for Evolutionary Anthropology census, 90% of all wild chimpanzees that live in Côte d'Ivoire (the Ivory Coast) are dead thanks to civil war, deforestation, poaching and clearing land for farming. Currently, Taï National Park is the last stronghold for a troop of chimpanzees while the remaining population lives in scattered locations all around Côte d'Ivoire.

Read the rest of the article from Examiner.com

Orangutan Turns 50, Thanks To Kitty

Everyone that knows me knows that I love cats. Cats are the perfect companion and the perfect friend. They never beg for you to drag them out on a snow storm to do their business and they even have the decency to cover their poop! OK enough talk about my cats, that's for my personal blog.

T.K. and Tonda at Zooworld, Fl. Photo from Cat Channel

An orangutan from ZooWorld, Florida named Tonda had adopted a cat name T.K. (short for Tonda's Kitty). Tonda went into depression four years ago after her mate, Yakut died. Faced with the facts that Tonda was too old for another male orangutan and was too fragile to be moved to another location, zookeepers tried a non-conventional method ... giving her a pet cat. Drawing inspiration from Koko, the gorilla who herself had a few pet cats, zookeepers began introducing T.K. to Tonda. It was a success. T.K. had been living with Tonda for the past four years and zookeepers think that he was the reason Tonda celebrated her 50th birthday. Read the article here.




What we can draw from this example, I think, is the power of pets or companion animals. Having a companion animal when we are lonely and sad seems inherent to humans but do great apes feel the same as well? Can pets really help rehabilitate other great apes, maybe even other primates when they are depressed, sad or when they just need a companion? One thing for sure, primates DO NOT MAKE GOOD PETS.

Bonnie The Whistling Orangutan

A female orangutan named Bonnie from the National Zoo in Washington DC knows how to whistle and she does it because she can. Bonnie's whistling was documented by Great Ape Trust of Iowa early last December. Her self-taught talent shed new light on the evolution of speech, said Bonnie's keeper Erin Stromberg. "Sounds aren't necessarily all genetic ... they also can be behavioral or ecological, and they are also voluntary", Stromberg added. BBC picked up the story last Thursday.

Bonnie whistles because she feels like it, not because for potential food reward. Researchers thought that orangutans have a limited number of sounds that they can make, all are involuntary responses based on emotions or to avoid predators. Bonnie's whistling certainly changed this perception. It turns out that Bonnie's friend, Indah also knew how to whistle. Scientists believe that Indah learned how to whistle from Bonnie. Indah died in 2004.

Bonnie's vocal plasticity might be the answer for the evolution of speech in orangutans or even the great apes.



"Orangutan’s spontaneous whistling opens new chapter in study of evolution of speech". Click on the Great Ape Trust of Iowa website or the .pdf version to read more.

Mirror Mirror On The Wall, Who Is That Other Gibbon?

Gibbons (lesser apes) have no use for mirrors, studies had shown (Suddendorf and Collier-Baker, 2008). They are not able to recognize themselves in front of a mirror. Typical human children starts to recognize themselves in front of the mirror around two-years-old. Mirror self recognition or visual self recognition is not unique to humans, it was only documented in great apes (chimpanzees, bonobos, orangutans and gorillas). Humans and great apes are different than other primates because they can recognize themselves in front of a mirror. Self recognition in front of a mirror enable them to see areas of the body where they cannot see directly. Self recognition probably evolved in the common ancestors of great apes around 18 million years ago.

Primate phylogeny. The ability of mirror self awareness probably evolved around 18 million years ago with great apes (chimpanzees, bonobos, orangutans and gorillas) common ancestors Image from www. mun.ca

A gibbon seems to be interested in itself, but none tried to get at icing on their own faces (Image: Emma Collier-Baker) Photo from www.newscientist.com

The gibbons sometimes tried to reach around the mirror to get at the ape on the other side (Image: Emma Collier-Baker) Photo from www.newscientist.com

Read more about "The evolution of primate visual self-recognition: evidence of absence in lesser apes" by Suddendorf and Collier-Baker, 2008 (full article) (abstract).

"King of the swingers has no use for mirrors" by Ewen Callaway on Newscientist.com

Citation:
Suddendorf T. Collier-Baker E. 2008. The evolution of primate visual self-recognition: evidence of absence in lesser apes. Proceedings of the Royal Society B (doi: 10.1098/rspb.2008.1754 ) http://rspb.royalsocietypublishing.org/content/early/2009/02/21/rspb.2008.1754.full

Our Toes Were Made For Running

Ever wonder why our toes are stubby instead of long and slender like our fingers? Long toes require more energy and generate more shock as compared to short toes, according to biomechanical analysis. Shorter toes are an adaptation favored by natural selection. Australopithecines, our first bipedal ancestor, had longer toes than our genus Homo but smaller than those of great apes.

"When you're walking, before you push off to start the next step, your other foot has already hit the ground. You've transferred some of your body weight. Your toes have to do much more work in running, to push you." (Rolian et. al, 2009)

Click here to read more.

Citation:
Rolian C. Lieberman DE. Hamill J. Scott JW. Werbel W. 2009. Walking, Running And The Evolution of Short Toes in Humans. Journal of Experimental Biology 212 (5): 713-721.