Thursday, September 26, 2013

Reflections upon returning

One revelation I've had since I've returned from Madagascar concerns water. Madagascar was not my first trip to a developing country, so I was fully aware that indoor plumbing and proper sanitation are not universal. Previous experiences had already made me very thankful and appreciative of toilets and having safe drinking water. But traveling to Madagascar and living at Berenty during the driest part of the year made me appreciate water in yet another way.
Mandare River during dry season

Water in Berenty comes from the nearby Mandare River. It's completely untreated when it comes to us, and it's the same water that people all along the river swim in, bathe in, wash their clothes in, wash their zebu with (a zebu is a type of cow), and etc. Where the researchers stay at Berenty, water is physically brought to us by a tractor three times a day. It's dumped into a well, and that's our water. That's the (cold) water I showered in, washed my clothes in, used for cooking, and drank. I brought with me a UV water purifier called a Steripen (which I highly recommend) rather than purchase bottles upon bottles of water to bring to the field. I purified no more than 1 liter of water at a time for my drinking water to kill any Giadia or anything else lurking, and then I drank my water. I could see little specks of dirt at the bottom, and as the river got lower and lower, I could see substantially more specks of dirt in my water.
Well for researchers' camp

The fact that I showered and drank and cleaned and cooked with river water that was untreated didn't bother me. It was what everyone else was doing, and how much can a little dirt hurt? So the not-pristine water didn't seem like a big deal. What was really eye-opening was having limited water. Everyone at the researcher's camp had to share this water, and it only came at certain times during the day. It wasn't as though if you ran out of water you just called someone up and they brought you more. There were definitely times where I went to grab some water for my lunch or my dinner or whatever and nothing came out of the faucet. (Then it was a matter of eat bananas for breakfast, which I did quite a few times, or some other sort of food that didn't need to be cooked). I took very short showers and never really got my long, thick hair clean because it required too much water. The one time I properly shampooed and conditioned my hair and had a good shower at Berenty, we ran out of water that night. No flushing toilets, no water from the faucet to brush your teeth in the morning, etc. The water for the morning didn't come until ten am, and we left for the field long before that, so I always had to make sure I had a full water bottle for drinking and another bottle of water to brush my teeth with every night. Better safe than sorry.
Ambosary Village near Berenty Reserve

Sundays were the worst. The tourist part of the reserve has electricity all of the time. The researcher's section has electricity whenever the nearby sisal plantation has electricity, which means we lost it every night and we didn't have it at all on Sundays. This meant no shower, no flushing toilets, no water out of the faucets at all. It also meant I had to make sure I had enough batteries charged for my Steripen because if that pen died, I was out of luck. Sundays were the hardest day at camp for sure. It's not fun to come back from a day in the field all sweaty and dirty and not have a shower. I also am pretty sure we didn't get our usual water three times a day on Sundays. We managed by saving water from Saturday in buckets and pots and whatever we had available. And then if we needed more water, it came from whatever was left in the well and it came to us in buckets. Rationing water for Sundays was a must. I tried to have leftovers for lunch and then I went to the restaurant for dinner so that I could use my computer and charge my phone with the electricity there. It also meant I didn't have a pile of dirty dishes sitting around until whenever the water showed up on Monday.

I am really thankful of having water whenever I want it. It's such a simple thing, but making sure I had enough water and wasn't using too much was a real concern at Berenty. I can take a shower now and use enough water to get my hair clean without affecting whether or not people can boil water for their dinner. I can always have a glass of water here, which is amazing.
Lemur drinking from puddle

And I am fully aware that, while I may have had it bad compared to western standards or compared to the tourists at Berenty, I did not have it bad at all. Many people bring their clothes down to the river to wash. They bring water back up to their homes. They don't have any sort of water at their house from a faucet or a shower or whatever. Allocating and preparing water was stressful for me when I first arrived at Berenty, and I didn't have to walk down to a river and bring water back to my home. The amount of time and energy some people must devote simply to access and use water is incredible. It's easy to see why the government or the people of Madagascar can't or won't devote more time to conservation when something as crucial as access to water (not even treated or safe water mind you) is still a real problem in many areas.

As I was leaving, the water in the Mandare, already very low, was getting even lower. Saotra, my assistant, said that, in the more populated places along the river, people are going to have to start digging to get the water they need. The wet season is November and December, so everyone needs to last another month before there's any hope of the river growing. I can't imagine how difficult it could become those last days before the rain.

Ex-situ conservation and conservation for the rest of us

Ex-situ conservation means protecting animals outside of their native habitat. This can include moving groups or populations of species to areas outside of their native range where they may have more success. It may mean bringing animals to zoos and trying to breed them in captivity to increase population numbers and/or genetic diversity. One example of ex-situ conservation is work the National Zoological Park is currently attempting to increase the number of cheetahs in captivity. The National Zoological Park are breeding cheetahs housed both at the zoo itself and at The Smithsonian Conservation Biology Institute in Virginia and trying to pair genetically valuable individuals. Many zoos have connections with field researchers, institutions, parks, reserves, and other sites across the world. These partnerships allow zoos to not just educate and inspire the local public and visitors but to be involved in projects that directly conserve species and areas through funding, providing training, acting as an area where orphaned wild animals unable to be released back to the wild can live, etc. The next time you visit a zoo, see if they have any programs that you can support or if your admission ticket goes towards any of these programs.
A former pet, this sifaka female now lives at a park

So what can and should you do, as a reader not living in Madagascar or other diverse and threatened areas of the globe?

Thankfully there are many things you may be able to do, and not all of them are terribly expensive or involve huge life changes. While donating to reputable organizations such as the World Wildlife Fund (WWF) is definitely an option, so is volunteering at your local zoo or for organizations such as WWF. You may even be able to find a volunteer opportunity that is virtual, so no matter where you live you can make a difference. Check out VolunteerMatch and search for opportunities there.

One step that absolutely anyone can take is simple awareness when it comes to purchasing products. Ordering that beautiful hand carved statue from Africa may seem like a great way to support the country, but where is that wood coming from? Was it sustainably harvested? Or are you accidentally contributing to deforestation? These same rules apply when you're traveling. It may seem like a great idea to purchase that unique souvenir, but you should know what materials it is made of and where those materials came from. It's easy to forget the impact our purchases can have when we support an industry that is clearing say the Amazonian rainforest or other endangered and unique habitats. You should be wary of where your wood comes from, your spices, your coffee, your chocolate, etc. It may involve a lot of research upfront, but eventually you will easily recognize the coffee that you learned comes from clear cutting forest in South America or Africa.
Farming even along the hillside

One of the largest contributors to deforestation of a very biodiverse area is the palm oil industry. Palm oil is planted all across Indonesia and Malaysia in areas that were once forested. Palm oil is in cosmetics, processed foods, shampoo, vegetable oil, popcorn, biofuels, and much, much more. 90% of palm oil comes from Indonesia and Malaysia, where deforestation is out of control and palm oil plantations are the leading cause. Plantations take the place of the habitat of orangutans, Sumatran rhinos,  Sumatran tigers, clouded leopards and other species. Roads cut for logging allow poachers to enter the forest, killing animals for the skins, capturing animals for the pet trade, and killing them for use in traditional medicine. Palm oil is an ingredient in so many items, and it is honestly not the easiest item to cut from your life, but it is well worth it. To learn more, start by checking out these websites, Rainforest Action Network, WWF, and the Orangutan Project.

In Madagascar, deforestation is a huge threat to wildlife. Forests are cleared for rice fields that feed Madagascar's growing population. They are cleared for charcoal production. Forests are also cleared for timber, some of which is highly valuable and is exported to be sold in international markets. In the south, where I worked, the unique and beautiful spiny forest has been replaced by sisal plantations. Sisal is a fiber that is used in baskets, ropes, clothing, etc. Many of these issues are internal, but you can be mindful of where your wood comes from to ensure you're not buying items made from unsustainable, Malagasy timber. If you travel to Madagascar, many of the souvenirs made for tourists are made out of unsustainable items.

If you're a student, consider joining groups at your school or university that focus on educating others about conservation and/or raising money for specific causes. If no such groups exist, start one yourself. I started a division of Jane Goodall's Roots and Shoots program at my undergraduate university. Roots and Shoots is aimed at young people across the world who want to make a difference. I am happy to hear that the division of Roots and Shoots at my university is still alive and trying to make a difference.

Sponsor a cutie like this one

You can also virtually adopt a gorilla or a lemur or many other animals through organizations such as WWF, the Dian Fossey Gorilla Fund, the Duke Lemur Center, and others. Or you can become a member and donate regularly to a cause. You can also purchase or sponsor your own section of the rainforest. If this seems like too much of a monetary commitment, you can show your support by promoting certain nonprofits and causes through your online activities, such as Facebook pages, Twitter, putting a link to an organization you care about in your email signature, and etc. 

Instead of taking a vacation to Paris or Disney World, take a vacation to Costa Rica and support local national parks and eco friendly tourist hotels. Or better yet, volunteer in some place warm and tropical for a vacation.  Earthwatch is a great organization that pairs volunteers with scientists, so that you can travel by yourself or even with your family and work alongside a researcher, learning and aiding a project. Volunteer vacations are becoming increasingly popular.

Visit somewhere off the beaten path and volunteer while you're at it
The main thing we can all do is educate ourselves on conservation issues and share our knowledge with others. The more people aware of the trouble that unsustainable logging causes or of the damage palm oil production does, the more people available to stop using these products and/or to demand viable alternatives. The more people aware that it's possible to take an exciting vacation where volunteering is a part of the trip, the more people who will try it. There's plenty to learn and this post is only the tip of the iceberg. I recommend spending some time on WWF's site, Googling Madagascar and deforestation issues there, and researching anything else from this post that caught your interest. The more you know, the more potential you have to make a difference. Conservation biology is an inherently depressing field, as being aware of the many hurdles wildlife across the globe encounter means realizing the long road ahead. It may seem like there is not much one person can do, but remember that a journey of a thousand miles starts with a single step.

Wednesday, September 18, 2013

Timing of reproduction

Ring-tailed lemurs and brown lemurs have begun to give birth here in Berenty. I’ve seen two infant ring-tailed lemurs clinging to their mothers’ bellies. I saw my first brown lemur infant briefly today (September 5). All I could see was a tiny head peeking out from a mother’s leg as she walked quadrupedally across the forest floor. Most primate infants are specially adapted to cling tightly to their mothers. Human infants have lost this ability, likely because humans don’t have nearly as much hair to cling to as other primates.
Sifaka infant and mother resting

Sifakas in Berenty typically give birth towards the end of July. Here, that corresponds with the start of the dry season. Why give birth during the dry season, when the leaves are falling and food is harder to come by? Why give birth during the most difficult time of the year? Well, giving birth and nursing an infant during the dry season certainly presents its challenges. But on the flip side of this coin, sifakas wean their infants when fruits are much more available, likely giving their offspring a better chance of surviving this period (if they made it through the dry season that is).
Ring tailed mother and infant nursing

Sifaka infants have reached the stage where they are a little bit stronger and more adventurous. I’ve seen them practicing their clinging and leaping onto tree branches a little bit. They’re venturing further and further from their mothers. Sometimes they even ride on their mother’s back for a bit. They have a bit more fur now, but quite a few still have those long tails that resemble a rat’s tail, if you ask me. I’m sure they resemble rats less when all of their fur has grown in.

Brown lemur mother and infant
There are multiple strategies when it comes to timing reproduction. Gestation of any infant is energetically costly. Just think about how much more a pregnant woman eats than a woman who is not pregnant. Lactation is also costly, as infants are growing at a rapid pace. Some primates produce milk that is rich in nutrients and fat so that infants are weaned quickly. Other primates have milk with a higher composition of water, and their infants are generally weaned over a longer period of time. There are pros and cons to each strategy. As a mother, it is in her best interest to produce as many infants that survive to adulthood as possible over the course of her lifetime. So, on the one hand she wants to wean her infant as soon as possible so that she can prepare for the next mating season. On the other hand, she wants her infant to survive and the juvenile period of development is a risky time for a primate. Timing reproduction so that birth is during a period of optimal fruit availability may make sense for some primates; timing infant weaning during a period of optimal fruit availability makes sense for others. Having dilute milk or having fatty milk is beneficial in different scenarios. Multiple factors come into play. I’m just happy I get to see more cute infants, although I have to confess, I think sifakas have the least attractive infants of the lemurs I’ve seen so far.

True or false: Primate infants consuming milk high in fat are generally weaned over a long period of time.

Critical thinking: How does this post connect back to the concept of biological fitness discussed earlier?

Critical thinking: During what season do humans give birth? Why do you think this is?
Infant sifaka grooming

Answer: False

In-Situ Conservation Part II

But creating wildlife parks creates jobs, doesn’t it? And it allows for tourists who bring money, right? Well, while Berenty certainly does have a large staff of guides, guards for the park, maids for the rooms, cooks and servers for the restaurant, the sisal plantation down the road employs far more people, and I’m sure it produces more cash.

Trash burning by sisal field
Madagascar is currently in the midst of trying to hold elections for a new president after a coup-d’├ętat. The election keeps getting pushed back and people protest and mini-buses (the main mode of transportation for Malagasy people) are occasionally attacked. While the violence currently appears to be limited to Malagasy and tourists have not been targeted (at the time of this post), tourists have reservations about coming here. It takes time and the right conditions for a country to become a tourist destination.

Rice fields in the countryside
Saotra, my assistant here, told me that he saw a boy with a bamboo lemur for a pet. Bamboo lemurs are critically endangered and were only recently discovered. I was immediately sad to hear this, but I know that every bamboo lemur counts when there are so few of them. For this boy, he may see a bunch in his “back yard” and not realize that the few in his “back yard” are all that is left. He does not know that scientists have only begun to study these creatures. He does not know that the species may not survive. And, even if he knows these facts, that bamboo lemurs are critically endangered, this may not have any real meaning to him. Having a pet bamboo lemur may just seem cool!

Sisal plantation where spiny forest once stood
Conservation efforts within a country must be undertaken only with substantial understanding of the life of the local people. Is the government stable? What are the religious beliefs of the local people? Is hunting primates taboo or is it allowed? Why? What are people’s choices in terms of jobs (are there any jobs)? It’s insanity to walk into a community, educate that community on how rare their primates are, and expect them to stop hunting primates if their religion/spirituality tells them hunting primates is a way to appease the gods or if hunting primates and other wildlife is the only way of keeping their bellies full.

Successful in-situ conservation efforts understand the local people they work with. Some examples of efforts that have had great success include Gorilla Doctors, which brings trained veterinarians to treat mountain gorillas harmed in snares or with other illness/ailments.

Critical thinking: You’re a conservation biologist tasked with educating a local community about the unique wildlife that surrounds their village. What must you take into consideration before attempting to your assignment?

Critical thinking: What might the locals be able to teach YOU about the wildlife surrounding their village?

In-Situ Conservation Part I

Conservation Biology is a booming discipline. I don’t know whether to add “fortunately” or “unfortunately” to that previous sentence. As the human population expands, there is less and less room for other creatures and living things on this planet. There’s only so much space to be had. Yet, many people are interested in protecting ecologically valuable areas, improving biodiversity, saving endangered species, etc.

Burning sisal to plant more
Conservation work is varied but there are two main categories of work: in-situ conservation and ex-situ conservation. In-situ means within the country. Examples of in-situ conservation efforts include transferring species to available areas, teaching locals about resource management, and creating protected parks within the country. Ex-situ conservation work examples include breeding species in zoos, informing people of the dangers of buying products made from wood harvested from the Amazon, etc.

This post is dedicated to in-situ conservation, or what I’ve learned here in Madagascar. Madagascar is currently experiencing rapid deforestation (like many places across the world), leaving primates and other flora and fauna with less and less space. So much of the life on this island exists only in Madagascar and it is a hotspot of biodiversity.

Fields for grazing and growing rice outside of Antananarivo
Forests are cleared for multiple reasons. It is cleared for charcoal, it is cleared to make living space for Madagascar’s increasing population, it is cleared for sisal plantations, etc. It may seem easy to judge and ask why a government or a people wouldn’t want to protect these unique species or ask how could someone possibly hunt and eat a primate, but let’s remember cultural relativism. Let’s remember to walk a hundred or a thousand miles in another man’s shoes before judging. I’ve done a lot of walking here, both in the forest and across all of the sand roads (no need to pay for a pedicure to exfoliate my feet, that’s for sure). Half of Madagascar’s population lives on less than one dollar a day. If you’re starving and have little money, of course you are going to buy inexpensive charcoal, which contributes to deforestation, over gasoline which is more expensive but better for the environment. If you can’t feed your family, then problems like preserving biodiversity hardly seem urgent. As for judging a country’s government and their priorities, investing roads so that people can travel to each other usually takes precedence over preserving parks. Lowering the illiteracy rate, creating jobs, and strengthening the economy are all likely more pressing to the general public and therefore the government than conservation.

Which of the following is NOT an example of in-situ conservation efforts:
A.   Foreign researchers hosting an event within the country where local biologists learn to apply for conservation grants to fund their work.
B.   Undergraduate students volunteering in local schools, teaching others about endangered wildlife surrounding their community.
C.   A WWF initiative moving endangered rhinos to protected areas.
D.   A fundraising event for cheetahs to increase money for zoos looking to help this species by increasing genetic diversity.
E.   All of the above are examples of in-situ conservation efforts.
F.    A and D

Answer: D

Sunday, September 1, 2013

Invasion of the fittest

Berenty Private Reserve is primarily a tourist site. The concern is with ensuring tourists have an enjoyable stay and see lots of lemurs right outside of their cabins. The few researchers who come to Berenty to work must contend with this fact.

Invasive vine that has been very successful
One of the problems that arise from Berenty being a tourist facility is the number of invasive species present here. Invasive species can take root anywhere, not just tourist sites. In Florida, work is being done to eradicate a species of land snail originally from Africa that can grow as large as a rat. The snail is thought to have been introduced by a religious group using the snail for ritual purposes. Asian carp were introduced on purpose in the Great Lakes to reduce algae levels. It turns out they eat pretty much anything and are completing taking over the Great Lakes and drastically reducing biodiversity.

Here at Berenty, certain plants have been planted for aesthetic pleasure. For example a row of cactus was planted along the road and the edge of the forest. This seems perfectly harmless at first glance. However, the inclusion of this plant in the ecosystem does change things. Lemurs eat the cactus, birds eat it, and before you know it you have cactus popping up in the forest itself. Cactus is popping up where it shouldn’t be and where it doesn’t belong. The same is true for other plant species brought in for aesthetic pleasure: they spread everywhere and find their way into the forest. These invasive species may be more successful than native species, driving out the original inhabitants and causing extinction of native species.

At least two of my three sifaka groups that I study I’ve seen eat from a species not native to this habitat. I’m doubtful it will affect my research, because I am looking to see if there are any differences between the sexes in their feeding habits. Invasive species certainly affects any researchers who come here to study diet. In fact, because of the introduced plant species and the provisioning of primates with human food that occurs at Berenty, this site could not really be used to study natural primate diet.

With the world growing smaller, humans travelling globally inadvertently bring seeds and invasive species with them. Primates and humans increasingly come into contact. Questions concerning primate diet in unnatural, altered ecosystems may be all that scientists are able to ask.

An unusual type of pest

Berenty is overflowing with lemurs. They’re everywhere. They’re completely habituated (used to humans). I can hear the ring-tailed lemurs and the brown lemurs on my roof, foraging on the tree above. I see brown lemurs multiple times a day drinking water from our well or from large puddles. I’ve only seen a sifaka drinking from the well once so far. The ring-tailed lemurs are very daring: they are in the kitchen, running around outside our houses, even in the dining room on the table. They’ll steal whatever food is left out and they’ve been known to sneak off with whole loaves of bread. They raid our garbage as well and anything that’s left behind in the kitchen. They sit on top of the roof. They sit on the side of the houses. They feast on the cactus that grows near us. They steal the cat’s food. Ring-tailed lemurs are basically like rats here. Being everywhere, they of course poo everywhere, which is not so cute.

Brown lemurs drinking our water
 Ring-tailed lemurs are also up in the tourist section of Berenty. In this part of the reserve, they enjoy stealing leftovers from the tourists’ meals and occasionally being fed by employees, even though this is forbidden. It sounds cute and the tourists happily snap humorous photos of lemurs eating banana peels or jumping on tables, but the reality is different. Feeding or provisioning animals leads to multiple problems. For starters, aggression within the troop will increase, causing physical confrontations and injuries and potentially increased infant mortality. The increase in aggression causes an increase in stress, making animals more vulnerable to disease. Animals become dependent on this outside source of food, causing a serious problem if at any point humans decide to stop provisioning the animals. Once used to a steady source of food, the troops may no longer have a large home range and the ability to expand and search for alternative food sources without entering into another troop’s territory, again leading to increased physical confrontations.
Ring-tailed lemur sauntering into our kitchen

Provisioning cute, little lemurs seems like a good idea at a first glance, but there are drawbacks that should be considered. Provisioning a group of primates is not a decision that should be entered into lightly. Yet there are troops of primates around the world where provisioning takes place and has so for years. These unique, experimental environments allow researchers to ask novel questions that wouldn’t be possible otherwise. For example, we know that provisioned populations generally have higher birthrates. 

Critical thinking: What other questions might be asked if studying a provisioned population of primates or other animals?

The more the merrier

Come on in! To one of our bedrooms...They have no shame.
Help yourself!

Saturday, August 31, 2013

Island living

Madagascar is the world’s fourth largest island. It is thought to have reached its present day location in relation to the African continent about 130 million years ago. Today, 400km separate Madagascar from the rest of Africa. Lemuriformes are though to have colonized Madagascar roughly around 65 million years ago, so how did the ancestors of sifakas, ring-tailed lemurs, and others arrive on the island? Are lemurs great endurance swimmers? Not exactly.

Madagascar's hissing cockroaches
What determines whether a species colonizes an island? Is colonization of an island something scientists can predict? The principles of island biogeography lend us a hand in determining whether or not an island will be successfully colonized by new species.

For starters, the closer the island is to the mainland or another large land mass, the more likely that island is to be colonized. The older the island is the more likely the island is to be colonized. The larger the island is the more species are likely to colonize it. All of these fancy rules are pretty simple once you think about them. The older the island is, the more time has passed, allowing species to reach the island. The larger the island is, the more space there is for all of those new species. And the closer the island is to other landmasses, the less distance between the two landmasses makes for an easier crossing for new species.

In terms of the genetics behind island biogeography, the following rules apply. As time passes and the island has been settled by those species that were able to the island and been successfully live there, genes are less likely to be exchanged between the original population from the mainland and the population on the island. As even more time passes, the two populations become genetically different.

Ancestral lemurs likely reached Madagascar by a series of rafts. This would have occurred not over a summer holiday but over an extended period of time in a series of events. As time passed, ancestral lemurs diverged from their original population and became genetically distinct. They thrived on the island of Madagascar and became the species we know today.

Girl power

Sifakas don’t experience a lot of feeding competition, from what I’ve seen so far, which isn’t surprising given their diet. If any feeding competition between a male and a female were to occur though, I bet you’d be surprised at who would come out on top. The female. Sifakas, like almost all of their primate relatives on Madagascar, have a social system in which females are dominant over males. Meaning the females can and do push the males around when it comes to any sort of feeding competition. It’s an unusual system to be sure, and no one is entirely positive as to how female dominance came to evolve.
Ring-tailed lemur sunning in early morning

One of the main theories is that female dominance evolved in response to the unpredictable environment of Madagascar. Females have feeding priority because it is advantageous for them to be healthy so that they can successfully produce offspring. Remember an earlier post about the term “fitness” in the field of biology? If females aren’t eating enough or are eating poorly, and they’re offspring aren’t surviving, no one’s fitness is increasing. It doesn’t matter if you’re a male or a female: the offspring need to survive. 

Like I said, I haven’t seen a lot of aggression in my time here watching sifakas. There seems to be plenty of leaves and flowers to go around. Every now and then, you will hear a rustle in the trees and some squealing, and it’s usually a female kicking a male out of his spot. Otherwise, everyone seems to get along rather peacefully, eating and sleeping all day long. If you’re a fan of girl power, these primates certainly have it. Other species of lemurs, those with choice food items, may experience higher rates of aggression within the troop, but sifakas are pretty laid back.
Lactating mother, Sarah Louise, with infant

Critical thinking: Can you think of a scenario in which female dominance would be beneficial?

Critical thinking: With unlimited funds and resources, how might you test your hypothesis as to what scenario might make female dominance beneficial?

Wednesday, August 28, 2013

Living with others

I spend my days alternating between three troops of Verreaux’s sifakas. Two of my troops contain six individuals and one troop contains seven. Verreaux’s sifaka group size ranges from one individual to up to ten members. Here in Berenty, I’ve seen quite a few groups with six or seven individuals. Although, group size is much smaller in the spiny forest, which is very dry and where food is potentially limited.

Resting midday
Most species of primates live in social groups. While some members may live on their own for some time after they disperse from their natal group to seek new mating opportunities, many primates will spend the majority of their lives living with others. Living in a group has its advantages and disadvantages. Living in a larger group means better protection against predators, such as snakes, birds of prey, and cats. An individual may feed and feel a little safer, knowing that multiple eyes and ears are on the lookout. Larger groups are also better able to defend resources, such as a valuable fruiting or flowering tree. Primates have competition from members of their own species and members of other species, and a larger group size may mean the difference between abandoning a food source or remaining and continuing to feed. This is especially true in instances where the food item is nutritious, such as fruit. Sifakas, consuming mainly leaves, don’t have a lot of competition from other troops of sifakas or from other primate species. However, there can still be instances where one sifaka will displace another sifaka over a valued food item, such as flowers. More members in the group means greater competition within the group.

This is one of the disadvantages of group living. Living in a group also means that primates must get along with each other. Just think of a time when you didn’t get along with a sibling or a roommate. Energy must be invested in maintaining harmony within the group. Sifakas usually get along pretty well with each other, from what I have observed. There isn’t a whole lot of social interaction. I’ve only seen some sort of aggression a few times, usually a quick squabble over food. I’ve seen the sub-adults play wrestling with each other twice now, but otherwise these primates mainly feed, rest, and groom themselves.

Troop clinging to trees
Madagascar is a unique country in that there are no cat species on this island. There are no lions or leopards to worry about. The closest animal this island has to anything resembling a lion is the fossa, which is actually not a member of the felid family at all but a member of the civet family. Fossas are small but they will hunt and kill lemurs. There are no fossas in this part of Madagascar though, so the primates in Berenty need not worry. Their main concern comes from aerial predators. Large group size protects them from predatory birds, as do other strategies, such as feeding lower in the canopy, which I’ve observed both the smaller ring-tailed lemurs and brown lemurs doing. Sifakas are relatively large, which may be part of the reason they feel safe feeding on the tops of trees.
Mother with infant on back feeding on leaf buds

Many variables affect the size of a primate’s group: food availability, space, predation, etc. If the local habitat is reduced drastically by human activity, a primate may not be able to disperse into new territory to find mating opportunities outside of its natal group, causing tension and aggression within the group.

Critical thinking: Can you think of other instances in which human activity may affect the group size of a primate population?

Sunday, August 18, 2013

Primate diet

Primates can be grouped into categories based on what their diet is primarily composed of. Primates that eat mostly leaves are called folivores. Primates that eat mostly fruit are called frugivores, mostly gums=gumivores, mostly insects=insectivores, and mostly meat=carnivores. There is only one solely carnivorous primate, the tarsier. This small Asian primate eats insects, lizards, and even small mammals. Tarsiers are solitary and nocturnal primates that truly eat nothing but meat.
Crocodile at Berenty  (in enclosure)

Sifakas are folivores. Think about the last time you ate a salad with only lettuce and other leaves. If you’ve ever attempted such a bland meal, was it filling? Probably not. Leaves aren’t exactly the most high-energy food item, so a lot of leaves need to be ingested if that’s going to be your diet. Leaves can also be hard to digest because they contain cellulose (it’s part of the plant cell wall and is what humans call “dietary fiber” in our diets). Some leaves may even harbor toxins that protect the leaves. Sifakas and other folivores have adaptations to handle these difficulties. They have a longer digestive tract than we do and they likely have behavioral adaptations as well. Leaves are low energy, and sifakas are low energy primates. Like many folivores, they do not spend a lot of time engaged in social activities. Rather, sifakas spend significant portions of their day just resting, conserving energy, and digesting their food. (They’re not the most interesting primates to do behavioral observations on, but they’ll suffice for my research questions.)
Sifakas feeding on flower buds

Now, just because we may call a sifaka a folivore does not mean that this species only eats leaves. Many species of primates consume a variety of food items dependant on availability. Gorillas are often classified as folivores for example, but they certainly feast on fruit when it is available. Diet composition can vary within a species too, if the species inhabits multiple habitats with differing food availability.

Critical thinking: Howmight a carnivore’s activity pattern differ from a folivore’s activity pattern? What other variables need to be considered?

Critical thinking: How might introduced plant species or other food sources introduced through humans affect a primate? Think about group size, aggression, infant mortality rates: would these increase or decrease?

Survival of the fittest

Baobab tree
“Survival of the fittest” is a phrase most people have heard of. Some people may even attribute it to Charles Darwin, although he actually adopted it from someone else. Many people don’t understand what the fittest means in terms of biology. An individual’s fitness is their ability to successfully produce offspring that survive to adulthood. I have a fitness of zero because I have no children. My sister has a fitness of two because she has two children. A primate mother who gives birth to twins, but only one infant survives to adulthood would have a fitness of one. An individual’s fitness is related to its adaptations, or traits that make an individual or a species better suited to the environment.

Introduced Brown Lemur on Trail
I am attempting to adapt by changing my project. I originally proposed to study four troops of sifakas. I wanted two troops in the spiny forest and two groups in the gallery forest. However, upon my arrival, I learned from my Malagasy assistant that there are only three groups total in the spiny forest, and each had one lactating female. We were able to locate two groups in our first few days but only one still had a lactating female. Given the scarcity of lactating females in the spiny forest, I have adapted to my environment and am only studying three troops in the gallery forest. I have five lactating mothers total, which is less than I wanted but this is the reality of the situation. We all have to adapt to our surroundings. A species may be perfectly well-adapted to it’s environment, but if a large change comes about, say humans start hunting that species, well then that species better adapt. Those most able to adapt to change are usually the ones most able to survive. Humans aren't exempt from change. 

Brown lemurs were introduced to Berenty, meaning they are not native to this area. The only diurnal primates at Berenty should be ring-tailed lemurs (Lemur catta) and Verreaux's sifakas. However, brown lemurs were introduced in 1975 and I have seen far more of them than sifakas. Clearly they have adapted to their new environment. They seem to be thriving as far as I can tell! The species of brown lemur at Berenty is actually a hybrid of two, genetically distinct species that bred together. They range wherever there is food, although they are a bit more timid than ring-tailed lemurs, the species of lemur Berenty is well-known for. The ring-tailed lemurs often steal food from the tourists and show up to breakfast for any table scraps left behind. Certain troops of ring-tailed lemurs have creatively adapted to the tourists here.

Critical thinking: Can you think of other examples of animals adapting due to their close relationship with humans?

Finding primates

 A question I often get asked is how we find the animals. Well, the short answer is we look. We walk around the forest, using trails if they’re available, with our heads craned up to see the highest branches. (Yes, it eventually hurts your neck a lot to do so much looking up). If we can’t find them using the trails, we start going into the woods. (If you’re lucky, you’ve got a machete to cut your way through-we didn’t.) Spider webs inevitably cling to your face. Thankfully, I have yet to find any large spiders clinging to me. You can also wave a stick in front of where you walk, like a magic wand, so that the spider webs cling to the stick and not your face. I do this often. Anyways, we search, and we search, and we search, and we listen. Sometimes you can hear the primates moving or hear them foraging. They drop leaves or they may break a twig and it falls to the forest floor. If you’re lucky, they vocalize. Primates are not entirely silent creatures.
Sifaka in gallery forest

In the beginning, when you’re new to a troop of primates you’re studying, there can be a lot of searching. You can spend hours of your week walking around, stopping and looking for the slightest movement. But there are some tricks to finding primates. If it’s first thing in the morning, they’re likely eating somewhere. If it’s cold out, they’re probably high up in the branches sunning themselves. If it’s the middle of the day and really hot, they’re probably resting in a shaded spot. Think like a primate! If it’s starting to get dark, they’re probably moving to their sleeping trees. Once you’ve followed the same troop for a few occasions, you start to know the area they cover and they’re habits. Maybe they have a particular sleeping site they often return to. Perhaps there’s one or two species of tree they really enjoy eating, so you search for those trees.

Can you spot the sifaka?

I think someone should do a study where they have radio-collared troops whose locations are always known, and then send a bunch of primatologists into the forest looking for primates. I bet you anything the primatologists walk right by the primates a few times. I think my assistant and I walked by the group we were trying to find at least twice today. Maybe three times. How hard is it to find seven white, sifakas in a green and brown forest? Well, if the sifakas aren’t moving and the bright sun is making everything look even whiter, it’s not a piece of cake.