Primatology.net

Gibbons seem to be all the rage, lately. A new biophysics paper on the gait of Gibbon bipedalism has been the most recent news that I have caught in my search of current events in primatology. The paper, “The dynamics of hylobatid bipedalism: evidence for an energy-saving mechanism?” was published four days ago in the Journal of Experimental Biology. It overviews how Gibbons moved on the ground based on the concern that there is some common energy-efficiency pattern in all primates that are fundamentally adapted to arboreal environments, but that can also stand up and walk. It turns out, they do just fine on two legs, but their gait is much different from ours.

Specifically, Evie E. Vereecke and two colleagues introduced an ‘instrumented walkway’ to the enclosure of four white-handed gibbons (Hylobates lar) in a Belgian zoo. As the apes ambled over it, their every move was filmed and every footfall recorded. The methodology reminds me of Eadweard Muybridge‘s studies on human gait.

Gibbons are anatomically much different than any other ape. They have outrageously large arms compared to their legs and rest of their bodies. This is because gibbon arm length is proportional to how the ape moves throughout its environment. The animals are much more often found swinging from limb to limb than “walking” on the ground.

Humans have two very distinct gaits, walking and running, gibbons only rarely engage in a way of locomotion that resembles our walk, where the legs are swung like pendulums. Instead, at all speeds, they propel themselves in a springy, bouncy fashion closer to our run. Here’s a video that I uploaded of a gibbon on the run.

And, unlike humans, Vereecke reports that gibbons do not use their Achilles tendons as the main spring. Vereecke hypothesizes that they might use their quadriceps muscles instead. Also unlike a human, they never have both feet off the ground at the same time. Vereecke suggests that this ‘aerial phase’ (think of this lovely expression on your next jog) should not be a requirement to call something a run.

The study concludes that gibbons make use of a energetically efficient spring-mass mechanism during bipedal locomotion.

The white-cheeked gibbon (Nomascus leucogenys) will be the next species of primate to get its genome sequenced by the National Human Genome Research Institute (NHGRI) in Bethesda, Maryland, accoridng to ScienceNOW Daily News. After decoding the human and chimpanzee sequence, the NHGRI has seen how the benefits of related genomes have helped medicine and other sciences; so the insititution has planned to sequence rhesus macaque, marmoset, orangutan, and gorilla genomes.

The work should help researchers understand primate and human evolution and the role of genes in disease, because related genomes provide a relative point of understanding what is a genetic difference between human and non-human primate and what is a genetic disease. The NHGRI plans to have the genome sequenced by three years…. but I think it will be done sooner.

Bushmeat is the term coined and commonly used for the meat of terrestrial wild animals, killed for subsistence or commercial purposes throughout the humid tropics of the Americas, Asia and Africa. Bushmeat species include apes, other primates, ungulates, rodents, birds and some invertebrates. The act of hunting bush meat is very common in sub-Saharan Africa’s dense forests, where endangered gorillas, chimpanzees, and bonobos, as well as other primate species live.

For quite sometime, it has been believed that bushmeat consumption widespread to only western and central Africa. This ignorance prevails because bushmeat is thought to be a form of subsistence hunting isolated to the poor of Africa, as a cheap form of food their families and villages. However, new evidence from Justin Brashares, a professor of wildlife ecology at the University of California, Berkeley and his team, show that they have found the,

“…illegal meat in markets in Paris, Brussels, London, New York City, Montreal, Toronto, and Los Angeles.

The team documented 27 instances of gorilla or chimpanzee parts being sold. They found that most illegal meat is carried in suitcases and also is shipped in parcels and large containers coming through JFK and Miami airports. Inspectors say they can only catch about one percent of the total coming into the country, sadly.

As culturally sensetive as I try to be I can’t believe there are some people that think busmeat is a delicacy. They must be outstandingly jaded. I won’t even touch the argument that the transport of this meat is less than sanitary… but what about the one that primates harbour pathogens that also affect humans? Ebola for instance is epidemic in chimps and gorillas, and spread to humans during the butchering and hunting of such animals. One of the many hypotheses that attempt to explain how HIV crossed over to humans is that the virus passed into people by this hunting and/or butchering of an ape, most probably a chimpanzee or gorilla. Hunting and butchering produces blood splatters that easily create infective aerosols.

All in all, you aren’t disgusted at this, then I don’t know what to say… I’ll just leave with some images of bushmeat from photographer Karl Ammann.

“An early bush-meat picture with a very representative story behind it. That morning we were pulled out of a bush taxi at a road junction to record a statement with the police. Our taxi went on with the rest of the passengers, and we had to wait for the next one the next day. We then met a hunter while walking along the road. He told us that he had killed a female gorilla that morning. The police chief of Moloundou—a town farther south—had sent him the rifle requesting him to ‘get some gorilla meat.’ He shot the female gorilla that morning and sent the gun and the carcass back on the daily bush-taxi run. He was allowed to keep the head and one arm for his efforts. He proved this story by taking us to his kitchen, where I took this picture after he lifted the basket that had covered the head.”

“Gorilla hands are considered a delicacy and are served to the guest of honor at official functions. The Dutch Catholic bishop of Bertoua told me that even after more than a decade in the region, he was still regularly served gorilla hands and feet—even after he consistently rejected them.”

“This person, on the way home from shopping at one of the Libreville bush-meat markets, carries a ‘bagged’ male mandrill. Libreville, the capital of Gabon, is headquarters to many Western conservation nongovernmental organizations. It is the one major town in central Africa where the meat of a wide range of endangered species is still openly on display.”

“This chimp orphan is being kept captive as a plaything for children.

“Crocodiles like this one have the misfortune of being transported alive in this tied condition. Fresh meat earns a higher price than smoked meat at the bush-meat market.”

“A fetish seller in Yaoundé displays snakeskins, many gorilla skulls, and an elephant jaw. A fetish is an object or an animal that is believed to have powerful magic that can help humans.”

“A hunter returning from a morning’s outing with a typical ‘bag’ of guenons. This productivity level will decline fast as soon as commercial hunting takes off.”

“A Pygmy butchers a silverback gorilla. They shot the ape on the way back from an elephant hunt after they lost a wounded bull elephant.”

While I don’t intend to shock what little reader base this site already has, there definately is a necessity to show videos like these to raise questions about the ethics of primate research. This video goes behind the scenes to uncover the mistreatment of mostly macaques at the Oregon Regional Primate Research Center. Matt Rossell captured this undercover video and narrates it.

On the coat tails of yesterday’s news on the threats to chimpanzee populations are two related articles on threats to gorilla populations. The first article from The Independent integrates many various sources to alarm us with news that…

“… within a decade, three of the four sub-species of the great ape could be wiped out.”

And by 2050, ALL gorillas will be wiped out if war, hunting, logging and mining continue to threaten gorilla populations. Currently, there are at most 120,000 gorillas total in all of Africa with Mountain and Cross River gorillas under 900 individuals.

Recently, I discussed how the encroachment of humans on gorilla habitats has affected their social group stability and affected their survivability towards infectious diseases such as the Ebola virus. One reason why gorilla habitats are being destroyed, and subsequently driven death by way of communicable diseases, is from deforrestation efforts from the mining industry. They are not to blame, though, the Worldwatch Institute has issued a report surprisingingly linking consumption of cell phones with endangering primates in the Congo. Coltan is a mineral needed for cell phone production, and with the rise of cell phone technologies throughout the world — the mines in western Africa are pumping out tons of this material, creating more demand to open newer mines. The depressing news is that instead of recycling for new coltan from the thousands of cell phones being thrown out everyday,

“it is being mined out of the eastern region of the Congo, which is making life difficult for the gorillas that live there.”

I got this news from Mobility Watch‘s commentary on how our lust for new technology is affecting the lives of these great apes. Next time you get the bite for a new hot cell phone, definately be conscientious that the act of buying a new cell phone so regularly really affects gorilla conservation efforts.

Jane Goodall recently spoke on The World Today about the threats toward chimpanzee populations with Conor Duffy, a correspondent for the show. What she had to say about where the chimpanzee population was one hundred years ago, where it was when Jane Goodall started her research, and where it is now is very depressing.

“it was two million a hundred years ago approximately, about a million when I began in 1960. Only about 125,000 now, which is nothing really spread over 21 countries. With the only really significant populations being in the great Congo Basin, and there we have the problem of foreign logging companies making roads deep into the heart of previously impenetrable forests and the hunters going in now, because they’ve got the road and they’ve got the transport of the logging trucks, and shooting everything, not the subsistence hunting that’s kept people alive for hundreds and hundreds of years, but commercial hunting: elephants, gorillas, chimpanzees, antelopes, monkeys, everything is shot, down to the bigger birds and bats, and smoked, and now it’s crept into the towns where the urban elite pay more for it than they do for chicken or goat.”

Goodall ends the conversation saying that with at most 15 years chimpanzee populations will be wiped out if we do not intensify our conservation efforts.

Should you be reading this blog, I assume you have a general understanding that primates are highly social mammals. Great apes, like humans, gorillas, and chimpanzees express even more complex social behaviors.

There are many consequences that living in social groups have towards survivability of the individuals of the group. Sociobiologists have often expressed that groups are natural selected upon just as individuals are in traditonal evolutionary theory — this concept is known as group selection which refers to the idea that alleles can become fixed or spread in a population because of the benefits they bestow on groups, regardless of the fitness of individuals within that group. The benefits a group can bestow, regardless of individual fitness, is higher predator awareness, more variation in foraging behaviors, and socio-emotional cohesiveness.

Groups can also be risky to individual survivability because all groups are regulated in size through environment. Groups which exceed in the size that their habitats can support them often crumble and lead to selective bottlenecks. Larger groups also bring about greater probabilities that disease will spread and effect more individuals compared to smaller groups. A brand new paper, published in Current Biology two days ago, documents a probable cause for why gorilla populations are on the decline compared to the rise of mortality due to the Ebola virus.

The paper, “Gorilla susceptibility to Ebola virus: The cost of sociality” is published from a group of French researchers who hypothesize that social contact facillitated the spread of Ebola virus among a population of gorillas in the Democratic Republic of Congo. This population is now only 3% of what it used to be in 2004. They finalize at the end of their paper that human group sizes have been most likely regulated by a similar disease diaster… but let’s read it in their own words,

“In an evolutionary perspective, this study provides direct evidence that, in hominoids other than humans, group individuals face a higher disease risk. This cost has probably been an important constraint to sociality evolution in early humans “

The authors have ulterior motives from this natural history and conservation tone. Instead, they are using this model of gorilla disease as a tangent to understand human socio-cultural evolution. They summarize that pre-humans were slow to live in large social groups because disease outbreaks could wipe out those who did.

I wouldn’t go as far as to say that’s true. The case for the dramatic spike in gorilla deaths due to Ebola has to be due to the devastation of deforresting and habitat destruction that are forcing gorillas to live closer to each other and in immediate contact to human civilizations, where disease runs rampant. Like I said before, ecology is a determining factor in group size and individual survability. I also say this because in the introductory paragraph the authors outline how the disease was transmitted to these gorillas:

“The large population of western lowland gorillas, Gorilla gorilla gorilla, monitored since 2001 at the Lokoué clearing, Odzala-Kokoua National Park, Congo, was affected in 2004, providing us with the opportunity to address both questions using an original statistical approach mixing capture–recapture and epidemiological models. The social structure of gorillas strongly influenced the spread of EBOV. Individuals living in groups appeared to be more susceptible than solitary males, with respective death rates of 97% and 77%. The outbreak lasted for around a year, during which gorilla social units (group or solitaries) got infected either directly from a reservoir or from contaminated individuals.”

Furthermore, other communicable and zoonic virii such as influenza can be transmitted from encroaching ecotourists and impoverished peoples living in Africa. These diseases are more likley to be foreign to gorilla immune systems, and would severly compromise their ability to fight off an Ebola infection.

Lastly, the more a disease is prevalent the more it emphasizes the increase the advantages of sociality, as outlined by Bonds in “Higher disease prevalence can induce greater sociality: a game theoretic coevolutionary model” In this paper, diseases bring about positive selection for more cohesive groups, whereas diseases more impactfully effect individuals living outside of groups because they lack the benefits reaped from social living (better quality & more abundant food, care, and protection from predation and other stressors). In addition, human immune systems are relatively more complex to other great apes, as are human social groups as in the form of culture and civilization — I most likely belive, then, that diseases bring about more incentive for groups to stick together…

…More importantly though, I think this paper documents the devastation, that even through inadvertantly actions, of the issues facing gorilla survival. I always wonder about well intentioned ecotourists who venture out to view wildlife, spefically gorilla populations and bring their illnesses and diseases with them. In their naivity they end up affecting great ape populations just as significantly as would a poacher or logger.

Here’s a video of Kanzi, a famous bonobo now at the Great Ape Trust of Iowa, playing Pacman. He definately gets into it and is more skilled than I at this game. Kanzi is an impressive ape all around, not only is he a legit gamer but he also has mastered the language board and stone tool making.

I want to congratulate Chimp Haven for earning full accreditation by the Association for Assessment and Accreditation of Laboratory Animal Care International (AAALAC). This accreditation is the gold standard for animal care and Chimp Haven recieved “exemplary” status in more than half of the inspected areas, which included feeding and veterinary processes, maintenance, and administration.

I’m happy to be reading this good news, especially since Chimp Haven houses around 60 chimpanzees and plans to bring in 90 more individuals. They have a beautifully forrested habitat on 200 acres of land. This is excellent news because the care of great apes is a significant undertaking, believe me, and for them to literally pass with flying colors on this rare but pretiguous recognition is outstanding.

I wish them the best of luck on getting American Zoo and Aquarium Association certification.

Normally, I wouldn’t dedicate a post to the death of a great ape for many reasons. One is that there are too many deaths to cover, and the frequency of morbid news isn’t something I’m going for on this blog. The other is that great apes are just a few of the many species of primates that die everyday.

That being said, I’m saddened to pass on the news that Kuja, a silverback Western lowland gorilla at the National Zoo, died under surgery to implant a pacemaker. Kuja was one year younger than I. I covered news of his heart problems a couple months ago on Anthropology.net, and at the time I was optimistic of his quick recovery.