What is a keystone species?

A keystone species is any species that plays a critical role in how the ecosystem functions. Couldn't one argue that every species is a keystone species, playing an important role? Well, a keystone species plays a disproportionately large role in maintaining the ecosystem structure and function.

Sea otters are a great example of a keystone species

For example, let's look at sea otters. They're a common example of a keystone species. Why? Well, because they feed on urchins. Urchins feed on kelp. By preying on the urchin population, sea otters prevent urchins from consuming too much kelp. Kelp forests are home to many species, including invertebrates, fish, and marine mammals. In addition to being important habitat, lots of other animals feed in the kelp forests, such as seals and sea lions. Kelp forests can be destroyed by urchins, but the sea otters feed on urchins, preventing this from happening. Without the sea otters to feed on the urchin, the urchin might consume massive amounts of kelp, destroying important habitat feeding waters for other animals. So the effect of this one species on the ecosystem is very large, larger than one would expect for a single species.

Many predators function as keystone species, limiting the population growth of multiple omnivores/herbivores. Wolves eat deer and deer eat small trees, so wolves protect this new growth. Jaguars, tiger sharks, mountain lions and sea stars are all predators that function as keystone species.

Pacific salmon is another good example of a keystone species and not because of what this species does during its life but because its death is so important. The salmon life cycle involves salmon returning to the freshwater streams they were born in to spawn (males release sperm and females release ova into the water) and then die. Like anything that's dead, the salmon then decompose in these waters. Their death provides a significant amount of nitrogen to the watershed (the area of land where all of the rain or water under the land drains to, click here for more info).  Salmon runs, when salmon return to the freshwater they were born in and spawn themselves, provide a crucial source of nutrients to areas that otherwise might have low productivity, and they act as a food source for many animals, including grizzlies and eagles.

Red mangroves

But let's not forget our green friends. Plants can function as keystone species too. Red mangroves, Rhizophora mangle, are found at the edge of the water. Their roots act as a nursery to fish and crustaceans. Red mangroves provide habitat for many species, such as manatees, birds, and fish, They protect against erosion and act as buffers from large waves, literally structuring the land around them by preventing soil erosion and acting as anchors.

The concept of a keystone species was first introduced by Robert Paine in 1969, who studied sea stars and noticed that removing this key predator had cascading effects. Since Paine's work, we've come to realize the importance keystone species have in their communities. These important species are often targets for conservation efforts, as conserving them protects many species and ecosystems.

Food for thought: Do some research on the reintroduction of wolves to Yellowstone National Park. How did the arrival of wolves in 1995 change Yellowstone? How is this example of a keystone species connected to conservation in Yellowstone?

If you want to learn more, check out this great resource from Nature: Keystone Species.

Orangutan called a "Non-Human Person," one that can be freed Part II

Yesterday, I wrote a post about an orangutan in Argentina that was recently freed by the courts after being declared a "non-human person." I found this interesting for more than one reason, and I wanted to share the second one today.

In response to this ruling, the head of biology at the Buenos Aires Zoo stated, "When you don't know the biology of a species, to unjustifiably claim it suffers abuse, is stressed or depressed, is to make one of man's most common mistakes, which is to humanize animal behavior" (see article here)  and I think this is an excellent and often overlooked point! I can't speak for this zoo because I've never been and I don't know anyone who has been. I can speak to my experiences at the Smithsonian National Zoo where I interned for several months as an undergrad.

Orangutan named Kiko crossing the O-Line at NZ

I would often hear guests complaining that the gorillas were just sitting there. "Why aren't they doing anything?!" Well, when you consider that gorillas are large herbivorous animals that spend much of the day foraging on leaves and another significant portion of the day resting and digesting those leaves, it makes sense that they're not always climbing trees and playing. Most primates spend very little time playing in the wild. I know the primates at National were extremely well cared for. They have enrichment time to keep them from getting bored, they have keepers who really care about them and have worked there for years, and they eat better than most humans do. Should apes be kept in zoos? Well, that's a hard question to answer.

I don't believe apes should be kept as pets or in the entertainment industry. They're not for our entertainment purposes and the idea of keeping a highly intelligent, huge, and strong animal in a home is absurd. Remember Charla Nash? Keeping apes in zoos may or may not be different though.

Zoos allow people to see and hopefully learn about many different types of animals they otherwise might never really learn about unless they can afford to travel. Watching a television program isn't the same as seeing a zebra in a zoo which isn't the same as seeing one in the wild. I saw a lot of children's eyes open wide when running up to see the gorillas feeding outside or the orangutans crossing on the O-Line, a series of long ropes and towers (electrified at the base so they won't want to climb down). Click here for a video of orangutans using the O-Line. I'd like to think these children (and adults) really enjoyed their time at the zoo but also learned a thing or too, including an appreciation for nature and wildlife. There's something magical about seeing an animal in the flesh.

Brown bear at National Zoo-Thankfully exhibits have improved greatly.
Historic Images of the Smithsonian

Now,  not all zoos are created equally. Some animals do live in very small confined spaces or receive inadequate care. I don't think large animals such as orcas should be kept in captivity at all. Just watch the movie Blackfish if you haven't already. That said, animals in zoos do tend to live longer than those in the wild. They receive medical care and lots of healthy food. They're also studied in a way that may not be possible in the wild. We know their lineages, we know exactly what they eat, we can watch them 24/7, and we can use cognitive tests as enrichment to understand their brains. There are definitely advantages to having zoos. Some zoos are centers of genetic or cognitive research. A few zoos even have excellent conservation science programs, funding scientists who study wild animals and initiatives that support the protection of wild animals and ecosystems.

Do these advantages outweigh the disadvantages of keeping animals in captivity? I'm undecided. Most zoos are aware of the problems they face. They want larger exhibits for their animals. They're trending towards creating the most natural environment possible. I hope this work continues and I hope zoos do more to ensure that visitors are actually learning when they come to the zoo. Do you stop and read the signs telling you all about a species or an issue? I'm not sure many people do, but creating more interactive displays, having keeper talks, and using technology may make the visit memorable and change perceptions. If the focus is on educating the public, conservation, and raising awareness about issues rather than making money, then zoos might be worth it.

Orangutan called a "Non-Human Person," one that can be freed Part I**updated

A case in Argentina is making headline news around the world.** An orangutan (an ape, just like humans are apes) has been ruled a "non-human person" that deserves corresponding, basic rights. The Association of Officials and Lawyers for Animal Rights successfully argued that Sandra, an orangutan born in captivity and currently housed at the Buenos Aires Zoo in Argentina, deserved freedom from the confinement she currently experiences.

I think this is an interesting story for a couple of reasons. For starters, the court did NOT rule that Sandra deserved the same rights as a human. The wording specifically states that she is a "non-human person." Now, what does that mean? Great question. It'll be interesting to see how this story develops. Humans, orangutans, gorillas, chimpanzees, bonobos, gibbons, and siamangs are all apes. Apes are characterized by larger brains than other primates and lack of a tail. We're more closely related to other apes than we are to lemurs or monkeys, but we're certainly a different species than our close relatives. We last shared a common ancestor with orangutans about 16 million years ago, meaning that orangutans and humans have been on separate evolutionary paths for this amount of time. That's a decent amount of time, and obviously a lot of differences have occurred since then. The phylogenetic tree, which represents the relationship between different species, shown below may help you visualize the relationship between different apes. Humans and chimpanzees last shared a common ancestor roughly 6-7 million years ago. We last shared a common ancestor with gorillas around 9 million years ago.

Tree showing the amount of time passed since humans split off from different apes. Humans are more closely related to chimpanzees than to gorillas. For more on how to understand phylogenetic trees, click here.

I do not think non-human apes should be awarded the same status as humans. However, I think awarding apes some rights may be a good idea but may also have unintended consequences. I am an advocate for animal rights in general, believing that it is our responsibility as intelligent humans to make sure that no animal is treated cruelly. Many primates live in complex social groups, they certainly display different emotions, and some even are capable of simple language. Regardless, non-human apes are not the same as humans. Before we brashly declare that they deserve to be considered the same as humans, we need to think about the potential consequences of those actions.

Primates are often used in biomedical research. Many believe primates should not be used this way (check out this link), but there are still those who believe we need to continue (read what proponents for primates in biomedical research have to say). The argument often used to continue primate biomedical research is that the number of primates used in research is very small and the number of humans helped is often very large. Whatever side of the line you stand on, declaring primates or just apes separate rights from humans will likely have a cascading effect on primates used in medicine.

I recommend listening to both sides of the debate on using primates for biomedical research before jumping to any conclusions. I'm a firm believer that there's no such thing as too much research so do your own on this issue! That said, I like that this orangutan was pointedly not declared a human. The zoo has time to appeal the court's ruling, which I would guess they will do. It'll be interesting to see how this case of non-human personhood plays out.

Tomorrow, I'll talk about apes in zoos and an important point an official of the Buenos Aires Zoo makes.

**The Nonhuman Rights Project obtained and translated the original court ruling and determined that the media got much of it wrong concerning this case. Nowhere did the court explicitly state that this orangutan nor any animal is entitled to rights and habeas corpus was not granted. Read more here.


Additional reading/links:

Non-human primates: the appropriate subjects of biomedical research?

 Primate tree

How human are chimps?

Should apes have rights?

How human are chimps? The differences and similarities between chimpanzees and humans.

The state of New York recently ruled that chimpanzees are not entitled to the same privileges and rights as humans. Chimpanzees have long given humans plenty to think about when it comes to defining what exactly is human. Jane Goodall, when she observed chimpanzees using tools in the wild stated, "Now we must redefine tool, redefine Man, or accept chimpanzees as humans." I decided to look at some of the ways chimps are just like us and some of the ways they're not at all like humans.

Young chimpanzee. Photo credit Sabine Bresser

Like humans:

1. Chimps taken from their mother at a young age suffer long-lasting behavioral consequences. Specifically, chimps raised by humans rather than other chimps groom each other less frequently than chimps raised by their chimpanzee mothers, and they also engage in sexual behaviors less frequently. Read the study done by Freeman and Ross at the Lincoln Park Zoo here. Looks like each species should probably raise its own young.

2. Chimps can cooperate and do so spontaneously. In a study where chimpanzees were given access to a task in a larger outdoor area, as opposed to a small, controlled area where most testing typically occurs, chimpanzees had the choice to use the apparatus and try the task or avoid it entirely. Surprise! Chimpanzees chose to use the apparatus, which required cooperation and choosing a partner chimpanzee to achieve the task, meaning chimps don't just work together when there's nothing better to do. These chimps sought cooperation out. Check out the article by Suchak and others here.

3. Chimps display different cultures, as shown by separate populations of chimpanzees using tools in different ways despite seemingly the same ecological conditions. A 2010 study examined how two populations obtain honey (a real treat for a chimpanzee) and found one population using sticks while another used wedges of leaves to soak up the delicious and highly coveted food item.

Unlike humans:

Photo credit Sergio Morchon

1. Chimpanzees may be able to communicate, but they have yet to display a mastering of complex language and grammar. While yes, chimps and other apes have a grasp of sign language and some even use computers and symbols to communicate with humans, are they capable of knowing the difference between sentences such as, "I bit the dog" and "The dog bit me?" The answer appears to be no. For a great film that I highly recommend, watch Project Nim. It's thought-provoking, heartbreaking, informative, and definitely worth a watch if you're interested in language or even more broadly interested in chimps.

2. Chimpanzees don't teach their young. Now, this might be a somewhat controversial claim since teaching in animals is hard to study (how do you determine if one it is one individual's intent to share knowledge with another?). Chimps certainly learn by watching other chimps and new behaviors are socially transmitted, but does one chimpanzee purposefully and knowingly teach another? Even if you disagree with me, you must admit that humans take teaching to a new level. With our creation of schools and our ability to guide and help others in a hands-on way, we take teaching to a level definitely not seen in chimps.

3. Finally, chimpanzees are not nearly as adaptive as humans when it comes to geography. Homo sapiens, or humans as we know and love ourselves today, weren't even the first to leave Africa and travel to other continents. Our earlier humans ancestors did that first, but the fact remains, humans love to travel. We have blogs dedicated to traveling, the desire to know what's just over that mountain or on the other side of the lake. We seemingly need to go everywhere and we're on every continent if you include the research done in Antarctica. We've adapted to all of these different climates through tools and clothing and behavioral adaptations. I don't think anyone can argue chimps have caught the travel bug quite like humans have.

Food for thought: Does learning these facts about chimps change the way you view what it means to be human? What is the most important difference between chimps and humans? What is the most important similarity?

Ten Stories to Be Thankful for This Thanksgiving

1. In Western Australia, a species once thought to be locally extinct (extinct in that area only-not globally), was spotted again after a decade long absence. Highly sensitive to habaitat disturbances, it seems like the spectacled hare-wallaby has managed to prevail.

2. Climate change and the need to be green are topics familiar to most people in western countries, but greening up practices is harder in areas where hunger and access to basic sanitation are real problems. That hasn't stopped Ethiopia from deciding to transform sewage to fertilizer and biogas. Talk about an interesting source of renewable energy.

Wind energy is more affordable than ever

3. Solar and wind power have been out of reach for most due to their high costs.  Prices are changing though and wind and solar power are more affordable than ever, with prices down 50-70% in recent years. While not yet a replacement for goal and natural gas, I'm thankful we're getting closer.

4. I'm proud to be an American after the U.S. pledged 3 billion dollars to the Green Climate Fund. The U.S.'s pledge puts us significantly closer to the goal of 10-15 billion raised (we're just under 7 right now). The GCF redistributes money from developed countries to less developed countries and helps them tackle climate change.

5. You've probably heard about the Galapagos Islands, a series of Islands with high biodiversity. Well, giant tortoises were once very near extinction on these islands, but they're making a comeback! Only 15 were left in the 60s but now there are over 1,000!

6. The second most populated country in the world, India, recently announced it will invest 1 billion dollars to renewable energy. They're looking to double their wind energy capacity by 2019. Way to step it up India.

7.  In what is one of the most exciting stories of an "extinct" species coming back from the dead I've read in a while, it looks like there's at least one Sumatran rhino left in the wild. Whether or not enough Sumatrans rhinos exist to maintain a sustainable population is uncertain and perhaps unlikely, but there might be some hope left, and that's good news.

Air pollution

8. Obama is expected to announce even stricter regulations on ozone emissions sometime today. I'm thankful we'll see less smog from factories and power plants. Everyone deserves clean air to breathe.

9.  Arizona residents have a new neighbor, not seen in decades, the gray wolf is back. A female wolf has been spotted wandering around the state. Let's hope a male decides to join her.

10. Finally, China and U.S. made the headlines globally when they reached a climate deal. China agreed to slow and curb carbon emissions. This historic deal means China will reach peak emissions by 2030 and then curb them, putting an actual deadline out there for the first time. This something we all should be thankful for.


Thanks for reading and Happy Thanksgiving! There's a lot of work to be done but there's a lot to be thankful for too!

Mean male chimps produce more offspring-implications for humans?

A study came out about chimpanzees recently that has received a lot of attention. You may have seen a headline on sites such as ScienceDaily, Smithsonian, and other websites stating that male chimps that bully females are more likely to reproduce. Specifically, researchers looked at 16 years worth of data from Gombe National Park in Tanzania (Gombe is where Jane Goodall first studied chimps). They found that males that were sexually coercive, or those or threatened or used force against females,  fathered more young than males that were less violent towards females. Male chimpanzees that acted violently towards females year-round (as opposed to just when females were receptive, or ready to mate,) were more successful. Those males that increased aggressive behavior towards females only when females were receptive did not have any advantage in fathering offspring.

Our closest genetic relative, the chimpanzee

Now, this study is a great example of how results and interpretations differ. It also presents the perfect opportunity to talk about how science reporters for the general public often misunderstand or sensationalize scientific research. News sites will get more people to click on their site if they use certain words and only report some facts to create a more interesting (although probably misleading) story.

The fact is, there are many ways to interpret this study, and the close genetic relationship between chimpanzees and humans means that of course we're all going to ask, what does this mean for humans?

Well, with sixteen years of data, there's certainly enough evidence to say that bullying females provides an advantage for chimpanzees at Gombe. However, how do we not know that these bullying males are aggressive with all chimpanzees, males and females and that aggression in general is the trait increasing their sexual advantage? Maybe this is the case or maybe not. My point here is simply that chimpanzees and complex and their reproduction and mating rituals are also complex.

Chimpanzee and offspring Photo credit: Neil McIntosh

It's not as simple as saying, "Oh, well if chimps that are mean towards females are more successful reproductively, the same must be true for humans." Many factors go into chimpanzee reproduction and many factors go into human reproduction. As similar as we are, we are not the same. Study author Joseph Feldman even states on ScienceDaily, "The glaring difference between chimpanzee and human mating behavior is that in chimpanzees females mate promiscuously with most male group mates during most cycles, while human females do not. Thus, the system that favors male coercion in chimpanzees is not present in humans to favor this behavior." The authors also point out a fact that all of the articles I've read so far seem to overlook: studies of chimpanzees at other sites have not found a link between sexually coercive males and the number of offspring they father. Thus, we need to remember that these results are specific to the chimpanzees studied at this site and not all chimpanzees in Africa.

The take home messages are; 1) be careful when reading about science from sources other than the original scientists and 2) with animals and biology especially, remember that simple studies are needed for us to ask answerable questions, but that the reality may be very complex.

What is an ecological niche?

What is an ecological niche? This is a question you'll probably encounter if you study primatology/ecology/zoology/etc. If I search for "niche" in the dictionary that comes with my Mac, I find that niche is "a position or role taken by a kind of organism within its community."  But what does that mean? Niche is a concept I found some students in the introduction to anthropology course struggled with, so let's take a closer look.

Some factors that contribute to niche

A niche is more than just the environment an organism lives in, it really is the role the organism takes (so the dictionary definition isn't entirely bad). It's not just where an animal lives, but the animal's behavior, what time of day its active in its environment, what foods it prefers most to eat, what foods it can eat when preferred foods aren't available, and so forth. How an animal responds to resources is part of its niche as is how it may respond to any predators. An animal's life history, or the sequence of events from birth to death related to reproduction, is also part of its niche. Many animals occupy the same environment. You could sit very, very quietly in a tropical forest for a couple of hours and see multiple animals exploiting a single fruiting tree.

If we just talk about primates for a minute, we may find one species of primate eats leaves from this tree. A second primate species consumes the ripe fruit on the tree during the day. A third species of primate ignores the fruit entirely, is only active at night, and instead hunts for insects and small reptiles on this tree.

Fundamental vs realized niche

This is an over simplified example though because a niche really is more than just diet or just habitat. Niches are complex. The actual or realized niche of a species may very well be entirely different from its fundamental niche, or the entire role/area a species could utilize in its niche if free from limitations. For example, while a primate that lives mainly on leaves may love to eat fruit, other competitors may prevent that primate from doing so. Thus, the realized niche does not include fruit but the fundamental niche does, because the primate is capable of foraging and feeding on that fruit. Keeping in mind the difference between realized and fundamental niche, different populations of the same species may have different realized niches. Let's say there are two populations of the same primate species but they live in slightly different patches of forest. Depending on the predators and conditions in each of those two forests, the same species may be able to exploit resources differently or have slightly different behavioral patterns because of lower predation rates in one forest compared to the other. Thus, the realized niches might differ.


Food for thought: I'd say humans have one of the most flexible and largest ecological niches of all species. Would you agree?

Here's a cool article about the first visualization of an ecological niche. Check it out!

Connections between Ebola, primates, and the bush meat trade

You may or may not have heard by now that many outbreaks of the deadly Ebola virus originated when people handled or ate animals infected with the virus. For those who need a refresher, a virus is an infective agent that is only able to multiply inside a host's living cells; a virus may cause an infection or disease. Fruit bats, primates, porcupines, and other animals can all carry the Ebola virus. It is only when a person touches or ingests the infected animal's bodily fluids (blood, sweat, mucus, etc) that a person risks infection. So, if you pet a chimpanzee on the head, which you're not crazy enough to do, you wouldn't risk getting sick, even if that chimpanzee was infected with Ebola (unless that chimpanzee had a very sweaty head). If you ate that chimpanzee for dinner though, you would risk contracting Ebola.

You may prefer a steak from a cow, but not everyone does
Photo credit: public domain

And there lies the connection between primates, Ebola, and the bush meat trade. Bush meat, or meat from animals that are not domesticated (bred or trained to need and accept the aid of humans), can be a primary source of protein for those living in Africa. Animals may be hunted by individuals simply to feed their own family, or animals may be hunted for commercial profit. More and more urban areas are consuming bush meat though, and in some instances this meat is even seen as a prized delicacy, a symbol of status and wealth.

As you've probably realized by this point, the bush meat trade can cause several problems. For starters, people may consume animals that are endangered or threatened, lowering their already low numbers. In Africa, the bushmeat trade is the most significant immediate threat to wildlife. While hunting primates and other wildlife to feed your family may or may not be sustainable depending on how the quantity and frequency of hunting, the abundance of the hunted animal, and other variables, the commercial bush meat trade is definitely not sustainable. Infant primates or other young offspring will die if their mother is hunted, leading to more loss. Concerning today's topic though, consuming bush meat leads to the transfer of disease from animals to humans. Thus, the bush meat trade is not only bad for the wildlife in the dinner pot but it's also sometimes quite bad for the humans eating out of the pot.

Bush meat in Ghana

 While the Ebola virus is thought to have originated in fruit bats, primates and other animals can carry it as well. Primates are especially a problem because we're so closely related to them. It's very easy for us to contract diseases from primates compared to animals we're not as closely related to. You may have heard that we share 98% of our DNA with chimpanzees, for example. Well, this close genetic relationship means that many of the diseases we can contract can be contracted by non-human primates too and vice versa. Hepatitis and herpes B can be transmitted from animal to humans, HIV originated in chimpanzees as SIV, and tuberculosis or TB can easily be transmitted from humans to non-human primates.

So in areas where bushmeat is the only source of animal protein available, you may purchase some meat at the local market, take it home and serve it up to your family for a filling dinner, and have unknowingly served an animal that was sick and infected with Ebola. While at first it may seem easy to place the blame on those consuming bushmeat, remember that many have consumed bush meat before without getting sick and may not realize that this is how the disease is transmitted. Those selling bush meat depend on this income to support their families. If people are educated on how Ebola is contacted and how unsafe bush meat is, the demand for it will hopefully decrease, preventing future outbreaks. Providing safe sources of animal protein may be another step towards decreasing the demand for bush meat.



Food for thought: How does this post connect with cultural relativism?

The creepiest primate

The aye aye

Happy Halloween! Primates usually don't come to mind when you think of scary animals, do they? But there's one in particular I think you may find a little creepy. It's the aye aye, an endangered lemur found on the island of Madagascar.

Aye ayes (Daubentonia madagascariensis) are a bit...different. They're the woodpeckers of Madagascar in a way. These primates have an extended third finger which they use to tap and find larvae from wood. Those large ears help them hear grub inside the wood. Once the aye aye finds something inside the wood, it uses it teeth, specifically its incisors (tooth at the front of the jaw designed for cutting: humans have four) to tear open the wood and get to the food! It may also use its third finger or digit to extract the food.

Note the long middle finger that helps the aye aye find food
 

Aye ayes are nocturnal and solitary. Like many primates, their numbers are declining due to habitat loss and hunting. Some Malagasy believe aye ayes are omens of bad luck/evil, so they may be killed for this reason. They may also be killed because they can destroy crops, and are thus seen as pests.

Here's a great video from National Geographic where you can watch this fascinating, creepy-looking primate in action: World's Weirdest-The Demon Primate. Enjoy!

Female Chimps and Male Attention

Everything is connected. More time spent resting means less time spent grooming. Less time spent grooming may mean greater chance of parasites and thus a greater chance of illness. Illness means greater chance of mortality. This is just one example of how everything is connected and one aspect of life affects another. The same is true whether one is a chimpanzee or a human. If you spend more time playing soccer with your friends, you will need to spend less time doing your homework. Or maybe you will compensate for that time lost doing your homework by working late into the night and sleeping less.

Chimps grooming, Photo credit flickr user Tambako the Tiger

One would think that receiving male attention would be a good thing, if one is a female chimpanzee. The more males seeking your attention, the more choice you have, right? The more opportunities to mate, and since an individual's fitness is a measure of the number of offspring one produces that survive to maturity, mating is an important part of life. So it's straightforward then. The more male attention, the better. Right? Not so fast...

A recent study led by Melissa Emery Thompson of the University of New Mexico found that male attention comes with costs. In the world of chimpanzees, males do indeed compete to mate with females. (Chimpanzees live in groups of multiple males and females and males are dominant over females.) A female will give birth to an offspring and then raise that offspring for five to seven years, which is a pretty long time in the animal kingdom. In part because female chimps raise their young for so long, males compete seriously for access to females. It's not as though the guys always have a chance with that type of reproductive schedule. Females will mate with multiple males, some of whom will then guard her to prevent other males from mating with her, so she can receive quite a bit of attention, whether she wants it or not.

For eleven years, researchers observed chimpanzee behavior and collected their urine to analyze or study hormones (naturally occurring substances that affect or regulate the activity of other cells or organs), such as estrogen and progesterone, which are two female sex hormones important for female sex characteristics and for reproduction. Emery Thompson and colleagues also collected urine to look for C-peptides, a byproduct of insulin. Declining levels of C-peptides indicate a female is spending more energy than she is currently consuming, which is not good.

Chimpanzees with offspring, Photo credit: flickr user Valerie

What they found was that females with more males surrounding them had lower levels of C-peptides and lower levels of those reproductive hormones. Thus, females with all of this attention are not consuming enough energy and are producing fewer hormones than needed. It appears that all of this male attention could very well stress out the females. Perhaps all of that attention from males means that females are less efficient at foraging and obtaining the food they need. Or perhaps they feel a need to keep an eye on those males, as males are dominant, and this extra vigilance is taxing or stressing. Whatever the exact connection is, it appears there are costs to having a lot of males around when cycling or lactating.


Food for thought: Why might female chimpanzees mate with multiple males? Hint: do some research into infanticide and think about how this might protect against it.

A lack of results, it happens.

Earlier this month, I attended the American Society of Primatologists annual meeting to present a paper. One of the talks I attended that I really quite enjoyed was given by Jessica Rothman, "Within-Species Variability in the Microhabitats of Mountain Gorillas (Gorilla beringei): Implications for Nutrient Balancing."  As I'm sure you've guessed from the talk title, Rothman, a nutritional ecologist at the CUNY in NYC, studies mountain gorillas, the fuzziest of the gorillas. Mountain gorillas are primarily folivores, meaning their diet is composed largely of leaves and herbaceous matter. There are very few mountain gorillas left in the wild and there are none in captivity, so of course Rothman studies the ones remaining in the wild.

Male mountain gorilla

Rothman noticed that the gorillas would sometimes bypass or ignore foods that they would stop and feed on at other times. She wanted to know why. Why would the gorillas pass up foods in one instance only to stop and feed on the same type of food in other instances? Some days gorillas will feed on these plants all day and other times they will travel right by them. That seems a little odd, doesn't it?

Sounds like a great question to me! To answer her question, Rothman collected lots of plant samples and recorded information about the microhabitat in which those samples were found. Variables she looked at included altitude, slope angle, topographic position, and areas of the park zoned for human use. She looked to see if gorillas stopped to consume plants at say a lower altitude for example and ignored the ones at a higher altitude, or if perhaps gorillas ignored foods in human-use areas and stopped to feed on the same plants outside of these areas.

Next, foods were analyzed for their nutritional value. The amount of sugar, protein, and fiber in each sample was determined as what the amount of tannins, bitter tasting compounds produced by plants that deter animals from feeding on the plant. Perhaps foods found in areas outside of human use are of higher nutritional quality than foods found inside areas that humans frequent.

Unfortunately, there were no real significant differences in any of the nutrients or tannins with respect to the microhabitat variables Rothman and colleagues looked at, especially when one considers what gorillas would be able to detect in terms of nutrients. 

Photo by Dylan Walters

Rothman found lots of nutritional variability within microhabitats, including variability within a single month, but as Rothman said, we're not yet able to explain this variability or were not asking the right questions.

This may seem like a disappointing result, and in ways it is. Of course as scientists, we like to ask questions and then have a concrete answer. We want to be able to say, "Gorillas are avoiding plants in high altitudes because the nutritional content of those plants is lower" for example, but that's not what was found. The reality is that sometimes we can't find a correlation, a connection or relationship between two or more things showing interdependence (note this connection or relationship is not necessarily causation), or an answer to our original question. Maybe we're looking at the wrong variables, maybe we're missing some key part of the puzzle, maybe there isn't a link there at all, or maybe our methodology isn't quite the best way to answer the question we're asking. This happens to all scientists regardless of the field.

A lack of correlations or findings is not a waste of time or complete loss though. New questions can present themselves or a new approach may suddenly become clear. And it's important to remember that we do learn from studies where no correlations are found. Scientist still need to publish their results and share them with others.




Food for thought: Why do scientists still need to publish studies where no correlations are found? Why is it important to share these results?

More food for thought: Can you think of how Rothman might use different methods to answer this question? What else might be causing gorillas to pass the same foods at some points in time and stop and feed on them at other times?

Higher Greenhouse Gases

A report by the World Meteorological Organization which was released Sept 9, 2014 found that greenhouse gases (gases in the atmosphere that absorb and emit infrared radiation such as carbon dioxide, warming the planet) are higher than ever previously recorded. The report reads, "Carbon dioxide or CO2 levels increased more from 2012 to 2013 than any year since 1984," showing that, despite increased attention to global warming, there doesn't appear to be any improvement.

How does global warming affect wildlife? What does any of this have to do with ecology?

Coral reef
Photo credit: Jim Maragos/U.S. Fish and Wildlife Service

According to the World Meteorological Organization, roughly 25% of greenhouse gas emissions are absorbed by the oceans, a further 25% are absorbed by the biosphere (life on earth, or the global ecological system), and the rest is then absorbed by the atmosphere. The oceans don't absorb all of these emissions without consequence, however. The result is ocean acidification, a decrease in pH caused by the uptake of carbon. Ocean acidification is thought to cause coral bleaching, a depressed immune response for some organisms, and reproductive disorders in certain fish. Lower pH levels are bad news for marine life inhabiting the oceans' dead zones, where oxygen levels are low. Dead zones with low pH levels are linked to increased rates of death and decreased rates of growth for young bay scallops and hard clams.

 It's important to keep in mind that this change in pH is happening suddenly and quickly. Organisms can't adapt fast enough and, like in a row of dominos, everything is connected. Food webs are affected, and the consequences could reach all the way to commercial fishing and the food we like to see on the menu.

Sea levels are also rising, which will certainly effect coastal ecosystems. Remember, warmer temperatures mean more evaporation, which will lead to more precipitation and thus possibly increased flooding in some areas. Rainfall is tightly linked to the types of vegetation that can grow in an area, and thus the animals that eat that vegetation. Hibernating animals, such as marmots,  wake up earlier or don't hibernate at all. Food sources for these hibernating animals aren't available during times when animals previously hibernated but are now awake, thus increasing the risk of starvation. I could give more and more examples (monarch butterflies changing their migration patterns, higher extinction rates, habitat changes for turtles, and so forth ), but I hope they're not needed.

Snares crested penguins

The effects of global warming are complex and potentially underestimated. What may seem like a small rise in sea level can have drastic consequences for multiple ecosystems. A seemingly slight rise in air temperature can mean a species needs to change its behavior, mating patterns, or habitat use. Changes to our planet are happening rapidly, as the World Meteorological Organization shows us. The question remains, what are we going to do about these changes? Are we going to do anything?



What do you think we should be doing to slow rising greenhouse gas emissions? How are different people and organizations (scientists, policy-makers, teachers, politicians, every day people, etc) responsible? What are some realistic approaches we could make to combat rising greenhouse gases?

SMART-A Wildlife Conservation Tool

From Stokes et al., 2010 paper

SMART, the Spatial Monitoring and Reporting Tool, is a conservation software that allows government organizations and other agencies to monitor and measure the effectiveness of patrols in protected areas. Data is input into the software and maps of patrol areas can be created along with maps showing where wildlife is being hunted or logging is occurring.

The creators of SMART are fully aware of the need to quickly assess and monitor areas, rather than rely on stale data. This is important because, of course, the world is not static; species ranging, human land use, ecologies, and so forth are always changing. Up-to-date data can be used by agencies to make key decisions about how to change patrols/conservation efforts. Management can then communicate quickly with patrols/those enforcing the law to implement timely adjustments.  Developed by conservationists to aid those on the "front-line," SMART is made so that managers can see what their current strategies are doing in real time and change them if needed. There's no time lag. No maps showing what species distribution looked like two years ago when new patrols or initiatives have been put in place. Managers can see where hunting is occurring now and then quickly arrange for new patrols in those areas. SMART is a useful tool because it detects these changes, so managers can see how implementing a new patrol affects species abundance for example.

The software also measures which conservation strategies are most effective. SMART has training tools and best practices developed by experts and people who use the software.

It's not marketed as for every one when in reality only those Westerners with a PhD can understand how to use the software. The creators of SMART worked to ensure their software would be put into actual use by field assistants, patrols, station managers, and so forth whether or not they have an advanced degree (or any degree at all for that matter). SMART is free and designed to be easy to use. It's available in local languages, and there's an online forum where users can post questions and help each other. Training manuals with modules designed to take users step-by-step through tasks such as, "Setting up a Conservation Area" and "Analysis: Queries and Summaries" were uploaded in May 2014.

Panthera tigris

The software has been used to monitor great apes and elephants in the Republic of Congo, tigers in multiple countries in Asia, and rhinos in Kenya.

I learned about this great tool in a talk titled, "Getting Smart About Great Ape Anti-Poaching Efforts by EJ Stokes of the Wildlife Conservation Society" by E. J. Stokes. I wanted to post about SMART for a couple of reasons: 1) it can and actually is being used by scientists and non-scientists; 2) it provides real-time data; 3) best practices are included with the program; and 4) it allows organizations to see what's working and what isn't. Using SMART, data and people can come together to effectively protect areas. It's just plain SMART! (Sorry, I had to go there.)

The ApeApp

I've had the privilege of attending talks at the International Primatological Society's Congress in Hanoi, Vietnam this week, and one of the sessions I made sure to attend was on the applications of technology to primatology and conservation.

One of the particularly interesting presentations was, "The ApeApp and Tablet Advocacy: How Best to Inspire Conservation in Mobile Technology" by L. Darby, D. Cress, and J. Refisch. With so many people using mobile devices (more people have access to a mobile device than a working toilet, I learned during the talk), it's no surprise that conservation has spread to our smart phones.

The ApeApp was created by the Great Ape Survival Partnership or GRASP to teach people about the Great Apes (Chimpanzees, Bonobos, Orangutans, and Gorillas) and to allow people to donate through their mobile phones to conservation causes. It's available for the iPhone, iPad, and Android devices for free and was a finalist for the Appy Awards. The ApeApp creates a link between the public and 95 partners of GRASP, ranging from research institutions to conservation agencies to UN agencies. You can donate to the Diane Fossey Gorilla Foundation, the African Wildlife Foundation, and others. Except for the PayPal fee, all of your money goes towards the cause you chose. I think it's great that users can choose to donate say to habitat protection with the Orangutan Conservancy or Congo Shipping project with the African Wildlife Foundation.

You can also learn about these projects you donate to. For example, the Congo Shipping Project provides local communities with a boat to transport crops to cities so that they can sell them, whereas before this project, many people could not sell their crops and thus resorted to hunting apes. The project also trains communities in sustainable farming.

The ApeApp also teaches users about these apes, providing information on the average size and weight of each ape, species habitat, their population numbers and conservation status, subspecies, sleep patterns, vocalizations, and, my favorite, food. There's plenty to learn and it's easy to use.

I think this is a great example of how technology and conservation and mesh well together. Next time you're on your phone, instead of playing games or checking social networking sites, why not spend some time learning about our closest living relatives? Or better yet, donate to a cause you learned about on the ApeApp through the ApeApp itself.

Fun fact: Guess how many hours Americans spend on some sort of technology (computers, radio, tv, mobile phones, etc)?



Answer: 11 hours!

Palm Oil Problems

Fruit from which palm oil is produced

Palm oil is an ingredient in countless household items ranging from cosmetics to food items to biofuels. It's become a huge conservation issue because the majority of palm oil plantations come from Indonesia and Malaysia, where forests have been cut down to put up these plantations, causing massive habit loss for animals such as orangutans, rhinos, sun bears, leopards, other species of monkeys, and many more animals. Deforestation has resulted in forests that are increasingly fragmented, making it harder for animals to find potential mates, to disperse, and making it difficult for those species requiring large home ranges to survive. Additionally, all of this cutting has resulted in increased greenhouse gases, contributing to global warming.

The demand for this popular vegetable oil is growing. Already 40-50% of the items found in homes in the US and one out of every ten items in supermarkets in the UK contain palm oil.

A recently published study (July 10) in the journal Current Biology report the need to prevent these large plantations from spreading to Africa. The article states that of the area deemed suitable for palm oil plantations, 42.3% of that area overlaps with the African great apes (chimpanzees, bonobos, and gorillas). Almost 40% of the distribution of great apes in Africa on unprotected land overlaps with areas considered suitable for palm oil plantations.  The authors determined that palm oil plantations will pose a significant threat to apes in Africa. In some countries, areas suitable for growing this crop overlap with ape habitat by as much as 80%.

Palm oil plantation

So what do the authors suggest to prevent palm oil companies from extending their reach even further into Africa? Public awareness of the environmental and social impacts (such as issues with water quality  and poor working conditions) this industry creates. Most people have never heard of palm oil, which can also be labeled as palmate, vegetable oil, Elaeis guineensis, etc. They have no idea of the destruction it causes to forests across the world. So what can we do to help? Be informed, tell your friends, and reduce your usage of palm oil as much as possible. It's very difficult to do, as palm oil truly is in so many products, but that doesn't mean we shouldn't try.



Food for thought: Apes have a very long life cycle. For example, orangutan offspring remain with their mothers until on average eight years old and won't give birth themselves until around age 15. When they do give birth, it's to a single offspring. How does this long life history work against them when it comes to conservation efforts? Think about population numbers.

General Bat Biology

One of the best parts of Piro Biological Station is that it is a true research station with multiple people from across the world coming to do their research in the Osa. A few weeks ago, bat researcher Melquisedec Gamba-Rios, a PhD student at the University of Tennessee-Knoxville, gave an introductory talk on the biology of bats. Melqui is at Piro for three months gathering data for his dissertation and I learned a lot from his talk.

Of the over 5200 species of mammals on this planet, bats make up 1200 of those species (21% of all mammals). They are the second largest group of mammals after rodents. Costa Rica alone is home to 117 species of bats.

Bats aren't blind, but they can't see very well at night. During the day, though, they see just fine. At night, they rely on echolocation, which you've probably heard of. Bats produce ultrasounds as they move and they need to keep moving so that they can send these sounds in different directions. They use their ears, of course, but bats also use their nose lip to "see" differences in textures.  They can move this nose lip to give direction to the sound they're sending out. They change the frequency of the sound they're sending out depending on their location. For example, bats will send out a flatter signal in an open area than in a forested one.

Bats roost in caves typically in the United States but they can also use holes in trees. Some bats in the tropics specialize in roosting in fallen trees over creeks or rivers. They have a social system with the alpha male roosting on top. Very uncommon are bats that roost on leaves in the tropics. There are bats that will make a tent-like structure out of large leaves by biting through the leaf to make a roost. Of the 112 bat species in Costa Rica, 17 modify leaves in some way.

Styloctenium wallacei roosting in tree

I was particularly interested in learning what Melqui had to say about the diet and feeding ecology of bats. Most bats are insectivores, consuming insects, but some species consume fruit, nectar, or even fish or small birds. One bat can consume 700-1000 mosquitos per hour. Fruit-eating bats are important seed dispersers, as bats will consume the juice of the fruit but spit out seeds, meaning these seeds remain intact and can grow away from their original tree. There are three species of bats that fish and two of those species live in Costa Rica (Noctilio leporinus and Noctilio albiventris) . They echolocate off of the water and can consume five to six tiny fish per night. These bats have adaptations to help them fish such as large feet and claws to snatch their prey out of the water. The echolocation these bats send when over the water is so loud that the bats will actually close their ears when they are directly over the sounds.

Of course, Melqui had to devote part of his talk to vampire bats, or bats that use their incisors (not their canines) to feed off of the blood of other animals. There are three species of vampire bats and they are all found in Costa Rica. An anticoagulant is in their saliva so that they can consume more of another animal's blood without it clotting. Vampire bats drink two teaspoons of blood per night and, if they don't eat for two or three nights, they die. To prevent death, bats can detect when another bat needs blood and can give it to them. However, this type of help only happens between family groups. Vampire bats will actually land close to their prey and then walk up to the animal so as not to startle it. Their nose is specifically shaped to detect hot areas of skin where blood is. And, while yes, bats can carry rabies, there are more problems in the United States with raccoons and rabies than with bats.

To learn more about bats, I recommend the following website: Bat Conservation International.

Food for thought: Why would vampire bats only help members of their own family? (Think about evolution and an individual's fitness, or ability to survive and produce viable offspring, thus contributing to the gene pool of future generations.)

The four species of primates found at Piro

Four species of primates can be seen at Piro Biological Station in Costa Rica. Squirrel monkeys (Saimiri oerstedii oerstedii), spider monkeys (Ateles geoffroyi), white-faced capuchins (Cebus capucinus), and howler monkeys (Alouatta palliata) are all monitored by the station with a focus on spider monkeys as indicators of overall forest health.  White-faced capuchins and mantled howler monkeys are both classified by the International Union for Conservation of Nature and Natural Resources as of least concern. Population trends for both of these species are unknown. Spider monkeys are classified as endangered, with population numbers decreasing and squirrel monkeys are currently classified as vulnerable with their numbers decreasing as well.

White-faced capuchin feeding

How do these four species exist in the same forest without conflict? Well, sometimes there is conflict, but these species differ in some ways. For example their diet and use of the forest is not identical, allowing each species to live together.

Howler monkeys predominantly consume leaves. They even regularly include mature leaves as a part of their diet, which is uncommon due to the high fiber content of mature leaves and relatively low abundance of readily accessible calories. Leaves aren't generally a desirable food item in tropical forests. Just think about fighting over lettuce: not a food item you'd fight over at the grocery store for. That said, you don't see howler monkeys fighting over leaves.

Spider monkeys specialize in the upper parts of the forest, including emergent trees and the upper canopy. They usually travel and forage high in the trees. Spider monkeys are frugivorous, preferring to consume ripe fruits if possible. Over 80% of their diet is composed of fruits. Spider monkeys consume fruit in the emergent level of the forest, where other primates may rarely visit, if ever. Ripe fruits are a desirable food item (I'm guessing you're likely to fight over a juicy peach than a piece of spinach), but spider monkeys are relatively large primates and, from what I saw, they typically dominate the other primate groups they encounter. Spider monkeys can also consume non-fruit items when needed/available, such as immature leaves, flowers, seeds, and even small insects.

Squirrel monkeys are also frugivorous but insects also compose a decent portion of their diet. These monkeys can use all levels of the forest but are mainly found in the lower canopy and understory, thus not overlapping with spider monkeys. They also seem to prefer secondary forest and river edge forests. When fruit is less abundant during the dry season, they increasingly depend on insects and other animal prey.

Squirrel monkey

Finally, capuchins occur in many types of forests (mangrove, dry deciduous, humid subtropical forests along with forests that have been degraded). Like squirrel monkeys, they can also be considered frugivores and insectivores. Their diverse diet includes fruits, seeds, flowers, frogs, and even small mammals. These intelligent monkeys, arguably the most intelligent monkey of Central and South America, are extractive foragers, meaning they can manipulate their environment to obtain foods that are embedded, sometimes using tools to obtain these food items. Examples of capuchin extractive foraging include pounding seed pods against the ground to open them, using sticks to probe for insects, and using specifically shaped rocks to crack open palm nuts.

How these four species of primates interact is not entirely understood. There is still much to be learned about interspecific competition, or competition between different species for the same resources, in Costa Rican primates.

To read more about these primates at Piro click here.