Primatology.net

A big topic of conversation in zoos and other animal facilities is stress: Who suffers from it? What are the causes and repercussions? How can we identify it biologically? And what are the best ways to recognize the causes in hopes of alleviating the stress?

We have all seen stress in animals (including ourselves) appear in some form of aberrant behaviors and other various conditions: pacing, head tossing (with carnivores), hypergrooming, displaying (like throwing feces or vomit), losing sleep, breaking out into hives, and self mutilation, just to name a few. While these behaviors and conditions are visual, concern also lies in what we can’t easily see… chronic stress resulting in suppression of the immune system, high blood pressure, stress dwarfism, fibrosing cardiomyopathy, etc.

Robert Sapolsky of Stanford University has been researching the physiological effects of stress on health (with a nice set of publications including both scientific papers and popular books) for decades and recently presented at the American Association for the Advancement of Science in San Francisco on Feb 17^th, 2006 (which I’m sad to say I missed). ScienceDaily highlights his research asking “Why Do Humans And Primates Get More Stress-related Diseases Than Other Animals?”

The bottom line is that:

“Primates are super smart and organized just enough to devote their free time to being miserable to each other and stressing each other out. But if you get chronically, psychosocially stressed, you’re going to compromise your health. So, essentially, we’ve evolved to be smart enough to make ourselves sick.”

Sapolsky helps us to think of it in terms of real stress versus psychological stress:

“During real stress – for example, something is intent on eating you and you’re running for your life – versus what your body does when you’re turning on the same stress response for months on end for purely psychosocial reasons.”

By constantly stressing ourselves out we are forcing our bodies to run in ways that are only intended for short bursts of time. We are essentially breaking down our system and becoming vulnerable to severe health problems (like those previously mentioned).

The baboon studies Sapolsky spearheaded are hugely relevant to this situation:

“We’ve found that baboons have diseases that other social mammals generally don’t have. If you’re a gazelle, you don’t have a very complex emotional life, despite being a social species. But primates are just smart enough that they can think their bodies into working differently. It’s not until you get to primates that you get things that look like depression.

The reason baboons are such good models is, like us, they don’t have real stressors. If you live in a baboon troop in the Serengeti, you only have to work three hours a day for your calories, and predators don’t mess with you much. What that means is you’ve got nine hours of free time every day to devote to generating psychological stress toward other animals in your troop. So the baboon is a wonderful model for living well enough and long enough to pay the price for all the social-stressor nonsense that they create for each other. They’re just like us: They’re not getting done in by predators and famines, they’re getting done in by each other.”

Needless to say, it’s important to understand more of the neuroscience behind stress. Sapolsky highlights some of the new research:

“It’s becoming clear that in the hippocampus, the part of the brain most susceptible to stress hormones, you see atrophy in people with post-traumatic stress disorder and major depression. There’s a ton of very exciting, very contentious work as to whether stress is causing that part of the brain to atrophy, and if so, is it reversible. Or does having a small hippocampus make you more vulnerable to stress-related traumas?”

Also…

“There are now studies showing that chromosomal DNA aging accelerates in young, healthy humans who experience something incredibly psychologically stressful. That’s a huge finding.”

Animals respond differently to every situation and stress is no exception. Understanding these differences, according to Sapolsky, is one of the most important areas of neuroscience research:

“This gets you into the realm of why do some people see stressors that other people don’t, and why, in the face of something that is undeniably a stressor to everybody, do some people do so much worse than others?”

It will be interesting to see how this research unfolds. Will it result in solid methods to understand how stress works? Will it lead to non-invasive biological markers of stress? Currently some researchers are relying on cortisol as a hormonal marker of stress. I’ve been to many a lecture reviewing the pros and cons of using cortisol in behavioral research, each generally ending with the same thought: cortisol is an accurate marker telling us that something is happening, but whether that something is bad stress (versus good stress, like riding a roller coaster) is still unknown. Some may say that the captive situations we’re using in research are more likely to prompt bad stress which would mean that cortisol is a better marker of bad stress than we are giving it credit for, but until that separation is apparent, we’re kind of back to the drawing board.

Understanding the animals that we work with can sometimes be a challenging job. Hopefully with all of the research going on in this field, we will be able to formulate a better understanding of what stress is (for each individual animal) so that we can do our best to identify and eliminate the stressors (and consequently the health problems).

I’m opening this post to a discussion of using primates in research as seen in the following video.

Feel free to throw in your two cents… but let’s lay down some rules. In order to participate, first watch the video and then I’ll subjugate you to kindly read my previous posts on this subject matter. But for now, the video:

The posts you should read, or at least skim over, are these four posts on the ethics of using primates in research.

In this video we see how a monkey, looks like a macaque to me, is being used to conduct neurotech research. This type of research is a bit different from biomedical ones, but its applications are outstanding and the potential is nearly irrefutable.

There are many ‘pros’ to this video. As the commentators indicate, most of the these ‘pros’ reside on the fact that tests like these prove that humans without functioning limbs… be it due to paralysis or other forms of loss of function… can now use robotic arms to conduct daily tasks.

This research is very important, in my humble opinion. But it comes at a cost, and these costs are heavy moral ‘cons.’

See how the monkey is trapped in a box? Well it has to be, because I’m fairly sure sure it wouldn’t sit a second doing what the researchers wanted if it weren’t restrained. Also, there was some invasive surgery done. Electrodes are placed inside the monkey’s brain that interface between neurons and the computer and robotic arms… something that is more permanent than putting a monkey in a box for 30 minutes or so.

Knowing those basic pro’s and con’s, how do you feel about research like this? Should it be done in this manner? Do you see anything wrong with it? Do you feel this research is justifiable, given the potential benefits from it?

Professor of Bioanthropology, Dr. Colin Groves, of the Australian National University’s Department of Anthropology has spent sometime studying a population of gray-cheeked mangabey (Lophocebus albigena). And his time spent studying this population has not been in vain. He actually found a novel trait in the skulls of this population of mangabeys, unique enough to be soon be designated as a new species, the Ugandan gray-cheeked mangabey (Lophocebus ugandae), as reported here.
I don’t have a picture of this new species to share you (to the right is a image of a regular gray-cheeked mangabey), nor do I have a publication where Groves documented his findings. Curiously, he,

“had not thought it a priority to publish it – [he has] so many other things to be getting on with.”

But he did present his findings at the International Primatological Society Congress in Entebbe last year and said he will now publish his findings because the forest this new species inhabits, the Mabira Forest, is threatened

“and the loss of this population would probably mean the loss of about a quarter of the total population of what now turns out to be an endemic species.”

Which is commendable. But that statement makes me wonder if the Mabira deforestation pressure not been around, would Groves ever publish his findings?

Furthermore to complicate the validity of this news species, Groves spoke candidly of his method that he used to speciate the new Ugandan mangabey. He calls his method ‘multivariate analyses’ which means to me one relies on two or more variable traits…. but all he shares with the news is one skull measurements! He intends to expand his study, using multivariate analysis to clarify whether other recognized subspecies of Lophocebus albigena can be broken to species level (osmani, johnstoni), which I think is a bit shakey.

I would much rather people sample DNA and use genetic analysis to define a species of primates. And in this case it is possible to do so. Genetic analysis is far more quantitative, definitive, and reliable than measuring skulls (which is a highly variable phenotype between sexes, ages, and environmental/health pressures of primates).

One of my favorite blogs, Neatorama, put up a link to a interesting internet find… a Japanese snack called Gorilla Boogers. Leave it to the Japanese to integrate ‘Engrish’, primates, and amazing marketing tactics.

Gorilla Boogers are described by the originating blog, Tokyomango, as

“a bunch of raisin-like black beans, I think, but they’re marketed as those funk-nasty snot rockets that caged gorillas like to shoot at spectators at the zoo.

Gorilla boogers were a huge hit among the hoards of kids going to Ueno Zoo for their school field trip. According to the Mainichi Daily News, it was the best-selling product at a nearby Kiosk a few years ago. “

I was in Japan at the time the Mainichi Daily News article was published, specifically November 2002 and I didn’t see this delicacy anywhere. I woulda surely picked up a batch!

Are there any Primatology.org readers out there who have tried Gorilla Boogers? If so, please share with us your experiences… I’m dying to know exactly what they taste like.

Remember when I told you that the genome of the gibbon was to be sequenced, all the way back in July of 2006? At that time, I assumed it will be finished sooner than the 3 years the NHGRI planned out for the project.

Well, I think my estimatation is right on track…. however researchers seem to have fallen into a slight speed trap.

One of the first publications has come out on this ape genome sequencing project, in the journal Genome Research. The paper is titled, “Molecular refinement of gibbon genome rearrangements,” which focuses on a interesting feature of gibbon genetics… that is also the speed trap.

See, gibbons have a genome that is rapidly evolving, more than other apes like us, gorillas, chimpanzees, etc. Parts of the gibbon genome is constantly being rearranged and broken up… which creates a problem for understanding and comparing genes between species. This genetic phenomenon is called karyotyping, and a unique arrangement is called a karyotype. If you are interested, a very prominent karyotype exists only in humans which distinguish us from other great apes.

Here’s a photo from the publishing team which,

“shows a split signal in human metaphase (chromosomes 6 and 9) and the inset image in the upper right corner shows a single signal in the gibbon genome. This is an example of a clone which spans the breakpoint of the rearrangement.”

Anyways, the whole scope of this paper is a report of these karyotypes and to open discussion on why certain karyotypes seem to evolve much more rapidly. The research also shows how Roberto et al. have developed unique ways to develop a framework in order to sequencing the entire gibbon genome, since they can’t really use a human one… due to the difference in karyotypes. Furthermore, the paper provides some insight on how evolution occurs with genomic rearrangement, as well as how chromosomes can become unstable in cancer and other genetic diseases (something I mentioned when I first anounced this project).

Here’s the abstract to the paper,

“The gibbon karyotype is known to be extensively rearranged when compared to the human and to the ancestral primate karyotype. By combining a bioinformatics (paired-end sequence analysis) approach and a molecular cytogenetics approach, we have refined the synteny block arrangement of the white-cheeked gibbon (Nomascus leucogenys, NLE) with respect to the human genome. We provide the first detailed clone framework map of the gibbon genome and refine the location of 86 evolutionary breakpoints to <1 Mb resolution. An additional 12 breakpoints, mapping primarily to centromeric and telomeric regions, were mapped to 5 Mb resolution. Our combined FISH and BES analysis indicates that we have effectively subcloned 49 of these breakpoints within NLE gibbon BAC clones, mapped to a median resolution of 79.7 kb. Interestingly, many of the intervals associated with translocations were gene-rich, including some genes associated with normal skeletal development. Comparisons of NLE breakpoints with those of other gibbon species reveal variability in the position, suggesting that chromosomal rearrangement has been a longstanding property of this particular ape lineage. Our data emphasize the synergistic effect of combining computational genomics and cytogenetics and provide a framework for ultimate sequence and assembly of the gibbon genome. ^“

The Howard Hughes Medical Institute has issued a press release with a more in depth discussion of the experimental design and results. I got the photograph from there as well as the description.

I am interested in keeping up with this research because there’s potential for an outstanding amount of information to come about from all of this. We can begin to understand how karyotyping, along with other types of genetic morphisms have been one of the selective forces in primate evolution, as well as apply this phenomenon to other aspects within science, such as medicine and cancer biology.

Late in 2006 we posted about a new question on Canada’s blood donor questionnaire and now it turns out that Ireland is following suit. Anyone who has handled monkeys or their bodily fluids will not be able to donate blood.

The reason is the same: the Simian Foamy virus.

It is noted that while the virus is common among those who handle monkeys, it does not cause any illness. However Dr. William Murphy, Medical National Director of the Irish Blood Transfusion Service states:

“But it (prevalence) is quite high and therefore professional monkey handlers have been excluded from donating.”

In addition to this news, the Irish Medical News reported another interesting bit of information. Those dealing with hemochromatosis (who are otherwise healthy and have donated within the past two years) are able to donate once again. With this genetic disease that effects more than 10,000 people in Ireland, the body absorbs and stores too much iron resulting in a necessary treatment of regular phlebotomies. A pilot scheme will open in 2007 for hemochromatosis donors in hopes of eventually screening the entire population. (For the USA, the Food and Drug Administration has always allowed those with hereditary hemochromatosis to donate blood, provided that the blood establishment follow procedures specific to their variance.)

With this in mind, we can hope that there will be improvement in the screening process for Simian Foamy virus so that those who have handled monkeys or their bodily fluids will not be eliminated as donors on that point alone.

We’ve heard of modern medicine helping zoo animals in many ways (including Salome, a western lowland gorilla at the Bristol Zoo reproducing with the help of fertility drugs) and the Port Lympne Wild Animal Park adds another success to the list: cataract surgery. A howler monkey named Tolkein relied on the help of her caregivers in daily activities since she developed cataracts as a juvenile.

The surgery restoring her eye sight was a success and after her recovery, Tolkein was introduced to a new arrival at the Wild Animal Park, Clyde. About a week ago, the two became parents of baby who is yet to be named…. a baby that Tolkein can care for with the help of all of her senses.

Simon Jeffery, a headkeeper at the Wild Animal Park reports that,

“At just a week old the baby seems strong and healthy and is very interested in its surroundings and so far Tolkein is being a perfect mum.”

Read the rest of this entry »

In case you were curious about seeing a video of chimpanzees engaged in nut cracking behavior and using stone tools, I’ve compiled a longer video clip from the small ones that Christophe Boesch put up on his Chimpanzee Stone Age press release page.

All credit goes to Christophe Boesh and crew, who recorded and shared the clips. I just edited the clips together and put them on Youtube.

Two news articles (BBC News and Live Science) are reporting a new archaeological find from Julio Mercader et al., who has discovered a deposit of stone tools at the Noulo site in Ivory Coast of West Africa. This site is known exclusively for being prehistoric chimpanzee settlement, and the find is dated to be 4,300 years old.

“The stones were much bigger than anything a human could use comfortably and bore the residue of nuts that modern chimpanzees like to snack on.”

The age of the tools was determined by radiocarbon dating the charcoal from the same ground layers the stone tools were in. The discovery represents the oldest evidence of tool use by our closest evolutionary relative.

Chimps stone tool usage has been going on for sometime; they have been observed using similar tools for the past few centuries. The origins of this behavior was thought to come from imitation, where chimps mimicked human’s using hammers and various tools. These stones now suggest the contrary, where now there is evidence that chimpanzees developed this behaviour on their own, or even that stone tool use was a trait inherited from our common ancestor. The age of these stone tools show us now that,

“chimpanzee material culture has a long prehistory whose deep roots are only beginning to be uncovered.”

I wonder something more globally than how and where this behavior came about, actually how does this finding change the concept of “man the tool maker?” While chimps don’t necessarily make these tools, they do select for stones that are more effective in cracking nuts. So how does this change Homo habilis‘ legacy and how we have, for the most part, ignorantly assumed australopithecines incapable of stone tool selection?

Julio and his teams’ report will be published soon in a February 2007 PNAS paper titled, “4300-year-old chimpanzee sites and the origins of percussive stone technology.” In the meantime you can check out the press releases issued by his co-author Christoph Boesch and also photos from the dig where you can see Julio and Chris excavating the tools:

Oh yes, this discovery is not entirely new, Julio Mercader published a similar albeit more preliminary discovery in 2002, “Excavation of a Chimpanzee Stone Tool Site in the African Rainforest.” You may wanna have a read at that before the paper in PNAS gets published.

“Chimpanzees from the Taï forest of Côte d’Ivoire produce unintentional flaked stone assemblages at nut-cracking sites, leaving behind a record of tool use and plant consumption that is recoverable with archaeological methods. About 40 kilograms of nutshell and 4 kilograms of stone were excavated at the Panda 100 site. The data unearthed show that chimpanzees transported stones from outcrops and soils to focal points, where they used them as hammers to process foodstuff. The repeated use of activity areas led to refuse accumulation and site formation. The implications of these data for the interpretation of the earliest hominin archaeological record are explored.”

Read the rest of this entry »

In the past, we have covered how pathogens like Ebola virus and Anthrax bacteria are causing thousands of deaths among great ape populations in Africa. In this post I will introduce another pathogen, one that causes Yaws disease, that is having severe affect on the reproductive success of gorillas, as reported by Florence Levréro et al. in the American Journal of Physical Anthropology. The paper is titled, “Yaws disease in a wild gorilla population and its impact on the reproductive status of males.”

A brief side-note, Florence was a co-author on the gorilla susceptibility to Ebola paper I reported on last July… so to say she knows a thing or two about wild gorilla populations and current pathogens affecting them is an understatement. And, before I get into the details of the paper, let me preface with some information on Yaws. Yaws is a tropical infection of the skin, bones and joints caused by the spirochete bacterium Treponema pertenue. This disease is similar to sphyllis. Symptoms of Yaws include:

• The disease is transmitted by skin contact with infected individuals or eye gnats, the spirochete entering through an existing cut or similar damage.
• Within ninety days (but usually less than a month) of infection a painless but distinctive ‘mother yaw’ ulcer appears.
• These tracts heal with keloid formation which can cause deformities, disabilities and limb contractures.
• The bone lesions caused are periostitis, osteitis, and osteomyelitis, damage to the tibia can lead to a condition known as sabre shins.
• In a very few cases a condition known as goundou is caused where growths on the nasal maxillae can result in extensive and severe damage to the nose and palate.
• Examination of ancient remains has led to the suggestion that yaws has affected hominids for the last 1.5 million years.

In the 1950s, Yaws was the center of attention of worldwide treatment program which sought to eradicate the disease. The program was successful among humans. So successful that the program managed to reduced the an estimated 50 million Yaws patients to nearly zero. But the disease is on the rebound as reported by the World Health Organization, just last month. According to Wikipedia, where I paraphrased all this information from, “Yaws is on the rise again, with roughly a half a million sufferers, mostly in poor, rural areas.”

Yaws’ growth among human populations, in Africa, is being transmitted to great ape populations, like the gorillas studied here, through flies. Flies are often found in places were there is overpopulation, caused by human development and deforrestation. Ultimately, as both Florence and I argued before, Yaws, Ebola, and Anthrax are products of human encroachment on gorilla territories. The acquired immune systems of these great apes did not have previous exposure to these pathogens, and made them ultimately more susceptible to these introduced communicable diseases.

Okay that being said, the authors studied how Yaws is affecting gorillas in the wild, specifically among a gorilla population in the Republic of Congo. The scope of the paper was limited to studying the reproductive success of gorillas with Yaws, and any conclusions drawn from that could indicate whether gorillas decided on mating or not mating with an individual infected with Yaws.

From what I can tell, and I am not completely sure about this, Yaws isn’t fatal… so they didn’t study the mortality. The bacteria seems to just manifest itself as lesions and causes deformities… but I don’t know if those lesions can get infected and compromise the immune system of the individual with Yaws.

Of the 377 gorillas, in population that was studied, about 64 of them had Yaws. That’s over 17%! As reported in the abstract of the paper, the trends in sex and age of the gorillas are as follows:

“Lesions were more prevalent among males than females above 8 years old. This sex-bias prevalence could result from the behavioral characteristics of males through a greater exposure to wounds. Lesions were also more prevalent in unmated adult males (either solitaries or those living in nonbreeding groups) than in males leading breeding groups.”

Here is an image, from the paper, of three infected gorillas with Yaws. Click the image for a higher resolution photo. In my opinion, this disease renders gorillas to look like ghastly gouls.

As I skimmed the paper, before I read it all, I wondered if there outward appearance affected their sociability?

In my mind the authors answered that question. They provided several examples that sealed the deal for me, but they decided on reporting their observations and conclusions modestly,

“Proportionally more unmated adult males presented lesions than did males leading breeding groups. In addition, breeding groups included no silverbacks at an advanced stage of the disease. This suggests that yaws is related to the competitiveness and vigor of males. Two complementary hypotheses can be formulated. Either affected males exclude themselves from reproduction because they do not have enough strength to compete with other males to gain and/or retain females, or they are not or are less chosen by females. Sexual selection by females could influence their decision to leave a group and their choice of group to integrate…

Since breeding groups led by affected and nonaffected silverbacks had similar numbers of immatures under 6 years old, these results suggest that the disease could have an impact on the reproductive success of males only at advanced stages….

For example, we can report the case of a skeletal adult female with a completely destroyed nose who became solitary after residing in a breeding group for at least one and a half years. During her seven subsequent visits to the clearing before disappearing, solitary males or adolescent males from groups that she approached rejected her and behaved agonistically towards her. Both a solitary life for a female gorilla and the rejection of an adult female by males are very uncommon. Given the cognitive abilities of primates, the question of social discrimination based on how gorillas perceive their partners with skin lesions warrants further investigation in the future. “

This is a double whammy for gorillas, actually make that a quadruple whammy. Not only do we have to worry about the regular three headaches such as deforestation, poaching and fatal pathogens like Ebola; but now conservation efforts are impacted because this new pathogen is affecting reproduction and gorilla social group cohesivity.

Although Yaws can be treated with several doses of antibiotics, how can people deliver that to wild gorillas? Instead, the authors advocate, as was done in the Ebola paper, that the pharmaceutical industry needs to roll up their sleeves and start working on vaccines for these diseases. There’s a lot at stake here.