Thursday, October 5, 2017

Paradise of the Páramo

By Tyus Loman

          Our car filled finished its ascension up from the Estación Biológica Cuericí. We pulled over to the side of the paved highway, where we met with a blonde woman named Jayne, whom I soon learned had spent her entire life in the Costa Rican páramo. She led us further down the road, until we abruptly turned right, away from the highway. Suddenly, we were in a small immediate clearing, covered with limited vegetation including shrubs and grasses. Beyond the clearing, endless hills and mountains of green surrounded us, extending in all directions. I am from Los Angeles, California – a dry desert with limited green, especially in the hilly areas of the city. The environment I then found myself in was new to me; rarely had I ever seen so much uninterrupted natural land, as even in US National Parks the presence of humans is always apparent. I knew that the opportunity to experience the páramo ecology with my small group of twelve, without a trace of any urbanization or vehicles, was one I was lucky to be afforded.
            We began hiking up a trail on the nearest hill, a trail so narrow I would have missed had I not been with our guide. The surface was rocky and dry, a comfortable hike outside of the steepness and altitude. The sides of the trail were dense with berry bushes; some were young blueberries that were healthy to eat, while Janie informed us that a similar looking berry, one which looked like a blueberry with a crown, was slightly poisonous. I broke a small branch of blueberries off a bush, and fed on the small berries hardened by their young age and cold weather. We stopped at the top of the initial hill, where Janie introduced us to a species of grass that was scattered throughout the area. The grass had a sharp edge to the point where running my finger quickly on it would have resulted in a cut.

            When we reached the top of the first hill/mountain, the landscape flattened out. Everyone took pictures of each other, eager to capture the vast landscape not covered by clouds. Once we had enough, we continued up the next hill to the next point. Near the top of the next hill, the group stumbled upon an alligator lizard – a beautiful, blue and green colored, quick little creature not quite the length of my hand. We were lucky to have caught it, and we all took turns holding the small lizard, while some people in the group allowed the lizard to nibble their fingers. At the next mountain peak, we caught an Emerald Swift lizard. This one was smaller than the other alligator lizard we saw, with a brown and black coloration. By tickling its underside, we were almost able to lull the creature to sleep, and some of us with better cameras could capture pictures of the lizard with its eyes closed. Those were the only two lizards my group could capture and release, with many others being too quick and seeking shelter under rocks before we could even move.
            Along the way, we continued to identify more plant families. All the plants we encountered in the páramo were small in stature, shrub-like compared to the trees of Palo Verde and other Costa Rican habitats. At one point, we came across a small patch of moss that covered the rocky ground, comparing in texture to a carpet. Outside of the small lizards we encountered, animal life was limited, perhaps to avoid the intense UV radiation of midday. Bird calls were not noticed, nor were bird sightings. Eventually, we reached the fourth peak of our upward climb, one which had a telephone line planted in the middle of the mountain. We descended downwards on the muddier, rainier side of the mountain. I slipped numerous times, and my clothes had the proof of this.

          We took a break for about half an hour, and I reflected on the páramo I had just seen. I was grateful to have had the opportunity to visit a different country to study and explore a limited biome, in a country that understood the importance of preserving its natural beauty. The lizards, plants, and landscapes we saw were now more than mere pictures in a textbook. My opportunities to see such an environment again would be limited, especially as climate change pushed the endemic species out of their limited space on the summit of the mountains. When we finally descended the mountain, my group and I were disappointed our time in Cuericí was quickly coming to an end. Hopefully a return is in my future.

Wednesday, October 4, 2017

Dead Things!

By Ray Hopkins

This is skeleton and skull of a Black Spiny-Tailed Iguana (Ctenosaura similis). I’m not sure if it was a male or female, but I found it while hitting softballs out into the soccer field and brought it back to the station for an ID. At first I thought it might be a snake, but the teeth are too flat and indicate a more vegetarian diet, which, combined with the size of the skeleton, points to a big lizard. Ctenosaura similis is the only iguanid species at the field station, so it was an easy deduction. What was really cool however wasn’t the species discovery itself but the teeth.

      There are two kinds of lizard teeth, pleurodont and acrodont. Acrodont teeth have no roots, and as a result are fused to the top of the alveolar ridge. If these teeth fall out, they cannot be replaced in adulthood. This kind of dentition is common in amphibians and reptiles. However, these are pleurodont teeth. Lizards can have acrodont teeth, but pleurodont teeth are lizard-specific. Pleurodont teeth are attached to the rim of a jaw. Fellow student Michael spotted this and noted that the teeth, as you can see in the second image, are pushing outwards rather than being straight up and down.
A drawing of reptile dentition, courtesy of Wyneken, J. “Anatomy and Physiology of the Reptile Mouth.” Pet Education, PetCo Wellness,,

In addition to finding deceased Ctenosaurs, I also found a very large and very dead toad this morning, likely a deceased Cane Toad, Bufo marinus. I didn’t think much of it, other than that it was pretty neat because I had never seen the carcass of an amphibian that had fallen prey to a predator. All the dead amphibians I had previously seen had been hit by cars or were cooked on the side of the road or fell victim to a parasite. There was never much to see until now. It looked like something had just ripped it straight down the middle and scooped out its innards as if with an ice cream scooper. It was really neat, the skin was discarded like a used plastic bag and the bones picked clean. What it really reminded me of was the movie “Cocoon” when the aliens discarded their human skin to show the old people their true selves. Over the course of the rest of the week that we were at the Palo Verde station, I saw dozens more disemboweled Cane Toads, and it never ceased to be a strange sight. One night, a group I was not a part of went hiking just as the rain began and saw a Cane Toad dragging itself along by its two front legs because its back legs had had the flesh sucked from them by a predator and they were now useless. I imagine that something, likely an opossum, either finished it off or it crawled into the tall grass to die.

When I got back to the field station. I showed one of the professors the picture and he said that because the frogs here have such toxic skin, the animals have evolved to flip them onto their backs and remove the meat through the belly so as never to touch the skin. Indeed, even after this they still refuse to eat the skin and instead leave it to the snakes. I found that super interesting. Imagine if the Australian fauna evolved to turn Cane Toads inside out, I’m sure that’d solve most of Australia’s problems right there. Buuuuut, on the other hand if they did catch on to that strategy we might not have the “Cane Toads: An Unnatural History” video so I’ve got some mixed feelings.
Finding dead reptiles or amphibians is usually not a common occurrence for me, largely because I live in a heavily fragmented area and reptiles and amphibians are no longer nearly as common as they were when I was in elementary school. Walking outside and seeing the evidence of thriving predator-prey relationships was pretty neat; usually the only deceased amphibians I find are killed my cars and there aren’t any interesting observations to be made. In the ripped body of one of the Cane Toads I observed later in the week was the partially digested body of a snake. I can only imagine that it must have been one upsetti spaghetti.

Tuesday, October 3, 2017

A Piece of Home in Paradise

By Michael R. Cornish

            Travel, travel we did. But before we did, we packed. We packed for a place I did not know, a place I could not imagine.  All we knew was that far up in the mountains near the continental divide, a man by the name Don Carlos ran a farm of some sort that was surrounded by preserve of dense, cool rainforest.  We were still in Palo Verde, a National Park in the province of Guanacaste, whose’ hot, humid air made it hard to image cool mountains.  Once packed, we loaded into the tube-shaped “coaster” bus and began our journey towards the province of San Jose.  Four hours pass; freshly-tilled rice fields with wood storks and rare jabirus looking for small fish and insects in muddy puddles, the pacific coastline of Guanacaste with large Dole container ships listing in the swell, and finally, the mountains of San Jose.  After a quick stop at the OTS headquarters, we departed for the preserve.  As we drove two more hours, the road took us up into the clouds. The mountains were shrouded in mist, concealing their immense height.  Unlike intrepid explorers, we dosed off, not knowing where we were nor where we were going.
            We awoke and got out of the coaster to a misty rain that made the cool air feel even colder.  The preserve was on a road to tight for the bus, so we walked the few kilometers down the its steep grade.  Eventually, we arrived; a building made of rough-cut logs fit together in a shingle-like fashion and covered in a steel corrugated roof had a sign labeled “Estación Biológica Cuericí”. We had arrived.
            The station, as expected, was surrounded by luscious forest with epiphytic plants draping the branches of the moss-covered leaves. A hike even had us see one of the only species of bird I had heard of before coming here, the resplendent quetzal.  All of these sights were astoundingly unfamiliar. This, however, was contrasted by what I least expected yet very familiar.
            Hailing from the green mountains of Vermont, cool, clear streams encased by coniferous trees are a familiar sight. And in the clearness of these streams, swam small trout that I enjoyed catching.  As we were given a tour of Cuericí by Don Carlos Solano and his daughter Ana (who now runs the farming aspect of the property), a series of pools of different sizes came into view that bubbled with the motion of hundreds of trout.  With the surroundings being so unfamiliar, the silhouettes of the fish and their conspicuous swimming patterns reminded me of home. This, however, proved to not only be a reminder of home, but also an amazing system that Don Carlos built.

            In a series of long, narrow pools, Don Carlos keeps the smaller fish that are still growing. With each successive pool, the size of the fish gets bigger. When nearing maturity, they are placed in a larger pond that is below those pictured.  This, however, is where it gets interesting; not only does Don Carlos raise trout but he also breeds them. When the fish would normally begin their migration up into smaller streams, Don Carlos opens up a small channel up which the breeding adults swim, thinking that it is a stream.  Eggs and sperm are then taken from choice fish and the fertilized eggs are placed into irrigated trays to develop and hatch.  The newborn fish (fry) go through a series of tanks as they grow, eventually to be placed into these pictured pools.  
            Once the fish mature and are ready for harvest, they are caught and put into pools that have especially clean water. This, Don Carlos says, improves the taste of the fish if they are kept there for a week or so before harvesting them.  The result of his efforts are large, beautiful, rainbow trout or in Spanish, “trucha”, like the one pictured below.
            Being able to see the system was a truly unique and amazing experience.  While our main interests in this course lie in natural systems, it was quite fascinating to observe one created and manipulated by the human hand in such a way.

Monday, October 2, 2017

Field Observations: A Return to Childhood

By Rowan Etzel

I've always loved spending time outside. As a budding scientist, I used to spend all my free time outdoors, sketching animals, mimicking bird calls, collecting insects, or simply watching the clouds change in the sky above me. In recent years, however, I've grown more distant from that part of myself, more caught up in the daily business of schoolwork and my various commitments and less connected to the world around me. I miss those days of immersion in the natural world, and one of my reasons for coming on this course was to regain that sense of immediacy and purpose.
On our first night at Palo Verde, I decided to take a walk down the road. Alone in the darkness, with just my feeble flashlight for guidance, I felt the forest come alive around me. Frogs were calling, bats swooping to catch the insects disturbed by my steps. The forest was teeming with life, and I felt present in a way that I hadn’t in a long while. At home and at college I love going on walks alone in the woods on a regular basis, but I’m so used to the woods of the northeast that they’ve lost most of their novelty to me, instead seeming more like a second home. There was such a distinct pleasure in walking outside to find a whole new ecosystem right there, and to be able to go access it whenever as part of the work for this course. I love writing field notebook entries, both for the simple organizational pleasure of ordering my thoughts as well as a physical chronicle of the creatures I see. Every day I’ve made it my goal to spend some time alone outside, taking some time to focus in on the butterflies, the ants, the birds, or just keeping my eyes open for whatever comes along.

The sheer number of the animals I see here daily is astounding. There’s just so much going on in any tiny area of ground. A couple of days ago I was sitting by the side of the road, watching and taking notes. In just a few minutes’ time I saw so many things that it was hard to keep up in writing them down. Several dung beetles rolled their cargo by my feet, slowly zig-zagging their way across the road. A hummingbird whirred by to dip its long beak into a hibiscus flower a few feet from my face, its colors darkly shimmering in the sun. Two different types of wasp were digging into the mud of a drying puddle, and several types of butterflies floated in and our of the underbrush. A white-speckle-winged bird and I spent ten minutes watching each other, with the bird alternating between rustling around in the underbrush and jumping out to sit in the road and cock its head at me inquisitively, as if I were the one being observed.
In conducting field observations, I feel an unexpected return to my childhood, when I used to spend hours watching the world around me. I've grown to realize that my study of science and research is improved by cultivating that childlike sense of looking at the world, of observation and inference without judgement. Such an unfiltered outlook allows me to collect information more objectively, and removes some of the inhibitions I've gained over the years. What drew me to science in the first place was the joy of discovering the world we live in, and there’s a lot to unearth here in Costa Rica. 

Sunday, October 1, 2017

Embracing Silence

By Anna Lee

The first time I stepped out on to the boardwalk overlooking the wetlands of Palo Verde National Park in Guanacaste, Costa Rica, I was met with silence. Not from the dozens of water birds strutting on the foliage or calling from the trees near shore, but instead, from my classmates. For once, this crew of extroverts had nothing to say. We were all so taken aback by the sudden appearance of acres of water and rings of mountains around us that we forgot to continue our conversation. For once, we weren’t asking each other questions or joking with people we had met only 72 hours before. We just listened to the world around. The overpowering natural beauty equaled us out as people. Nothing anyone said could have been as exciting as the stories unfolding all around. No one’s life was more colorful than the red, green, and purple dragonflies skimming the water or carefree as the spiny tailed iguana blocking the entire pathway. I think in that moment we all realized that no matter what brought us to Costa Rica, we  all arrived with the same purpose: to use our skills and passion to better understand and preserve the breathtaking landscape around us.

            While that silent moment didn’t last, I keep it as a reminder I’ll carry with me for the next 13 weeks as our program unfolds. Nature will not let itself be silenced by loud voices or careless conversation. Nature is not passive. It demands attention with grace. And when it is ignored, it has the potential to become violent. The day after my first encounter with silence in the wetlands, a classmate and I were walking along the shoreline completing an assignment. Suddenly we heard a splash, a snap, and alarm cries rise from the water. In the midst of our superficial discussion about our home universities, a crocodile had come up to eat one of the Northern Jacana birds that call the national park home. In seven seconds and without words, nature had told us a story of life and death more exciting than anything we could tell ourselves. Once again, nature reminded us of its power and at the same time, its fragility. When you fully experience the sights and sounds that exist in our world, there is no pressure to impress anyone. You never have to fight for a moment to speak, or make up a story to impress a classmate. It is time we all get used to never being the center of attention and let our world have the spotlight it deserves. While we all want our voices to be heard, sometimes you just have to embrace the silence and let Mother Nature speak for herself.  

Saturday, September 30, 2017

Starting off at Palo Verde

By Finote Gijsman

It’s been two weeks since the start of the OTS Tropical Biology on a Changing Planet program in Costa Rica, and I can say that it’s already been quite a journey. The first field site we went to was the Palo Verde National Park in the Tempisque Conservation Area. Palo Verde is home to the endangered tropical dry forest ecosystem and a large marsh ecosystem that attracts many species of birds year-round.
On our first few days in Palo Verde, we familiarized ourselves with the park and its different ecosystems. Prior to the program, I didn’t really know much about the tropical dry forest, so it was interesting to learn about and experience it first-hand during our walks. Considering that this ecosystem is highly threatened due to habitat conversion by humans, I feel very privileged to have the opportunity to study one of the last significant fragments of tropical dry forests in Central America. This ecosystem is considered a “tropical dry forest”, because precipitation is highly seasonal and more limited relative to other wetter areas in the tropics. With long dry seasons that last several months, many plants shed their leaves to conserve water. We, however, were there in the middle of the wet season, so we were lucky to see many birds using the marsh. These included the green heron, boat-billed heron, and black-bellied whistling duck.

Later in the week, we hiked up to a lookout point in the park for the sunset. Along the way, we were greeted by a pair of white-headed capuchin monkeys. The two were resting in the canopy and did not seem too happy to see us, as they flared their teeth at us. Once we made it to the top of the hill, we were able to briefly watch the sunset over the wetlands, after which we rushed back to the station to avoid the evening showers.
In the evening, we got a talk by one of the researchers at the station, Davinia Beneyto, who is studying the crocodile population of the Tempisque River basin. The male: female sex ratio of American crocodiles in this region appears to be very male biased, with approximately 3.4 males for every female. The cause for this skewed sex ratio has not yet been determined, but Davinia and her colleagues suspect that the use of a hormone, 17α-methyltestosterone (MT), in nearby tilapia farms may be the reason. Tilapia farms around the national park are known to raise fish using food that is laced with the hormone to convert females into larger, more profitable males. With these crocodiles being apex predators, it may be that fish from the nearby tilapia farms are being eaten by the crocodiles at the Palo Verde National Park and in turn affecting the crocodiles’ endocrine system. Such findings may have large implications for the vulnerable American crocodile population at the Palo Verde National Park and possibly even Costa Rica as a whole. The biased sex ratio may be even more startling, because climate change is predicted to affect the crocodile sex ratio in the opposite direction, by favoring females. Crocodile nests are known to be temperature sensitive, with the sex of the baby crocodiles being determined by the temperature of their nests and not genetically. Hormones may therefore be driving a major shift away from what is naturally predicted by regional warming at Palo Verde.
I personally found this crocodile research program fascinating. I had never really heard about temperature dependent sex determination, but to learn that what was being observed was the opposite of what was expected with climate change, was even more appealing to me. Being a plant biology major, I have mainly been exposed to the way research works within that field of study, so I came into this program hoping that I would get to explore other fields in biology and learn about how the research methods within them. While the program has been field-work intensive, I have really enjoyed getting to branch out and learn about other systems. It has been very refreshing to get out of the organized lecture/classroom setting and be able to interact closely with professors specializing in many different subjects.

Friday, September 29, 2017

Catching Túngara Frogs in Palo Verde National Park

By Genevieve Valladao

Up until a week ago, I had never touched a frog. I prefer big predators – jaguars, sharks, crocodiles – organisms that humans aren't able to just grab and play with. So, when I found out that one of the first research projects I was going to be working on in Costa Rica involved trapping frogs I was a little nervous. The project was designed to test for effects of Belostomatid (Lethocerus annulipes) predators on site selection of prey Túngara frogs (Engystomops pustulosus). It involved capturing Túngara frogs at ten different sites, marking each of them individually, applying a treatment of Belostomatid chemical cues to half of the sites the next day, and then checking the sites the next night to see how the dispersal patterns of the frogs were impacted. Túngara frogs mate in small pools of water, so the study sites for our experiment were large puddles along the dirt road outside of the Palo Verde Research Station. Our program was split into two groups, each going out to catch frogs a different night and I was assigned to the second group.  
Photograph courtesy of Ray Hopkins
            Group one caught 48 frogs individual frogs the first night of the project, but also came back covered in mud and mosquito bites. Their complaints made me even less excited to go out the next night. But when night rolled around the following day, I put on my rain gear, rubber boots, headlamp, and face mosquito net, and headed out. I was unsure of what to expect. “Okay,” Brian said about 100 meters from the station, as we came up on our first puddle and he handed each of us a small plastic bag. “This is our first site.  Surround the puddle, grab as many frogs as you can, and drop them in your bag.”  Before I could question how I was even supposed to catch a frog, Brian and the rest of the students were along the edges of the puddle, shining their lights in the water.  Two frogs were caught at our first site.  As Brian tagged and documented one of the frogs, I watched the way he held it by the back leg.  “Can I hold it?” I asked - I did not want the first time I had to hold a frog to be one that I was trying to catch for our project.  I was not at all confident that I would be able to hold it without either hurting it or letting it go away.  Brian handed the small frog off to me and I got to get a good look at it - it was a male so its throat was stretched out from calling to females, which was amazing.
Photograph courtesy of Milena Cambronero
            We didn’t catch many frogs the rest of the night, possibly due to the puddles being small from a lack of rainfall.  And I stayed in the back of the group when we would approach a site, so the few frogs that we caught had already been captured by the time I came up on the site.  Sometimes, after a frog had been tagged and released, I would try to recapture it for practice.  Sometimes I would be able to catch it, and other times it would slip through my hands. I was relieved coming up on the last site – I hadn’t been the first to spot any frog so I hadn’t had the pressure of catching one.  But as I ran my headlamp over the puddle, my light illuminated something in the water – a Túngara frog.  I palmed it, just as Brian had instructed, and was able to pass it off to be marked.  I had caught my first frog for our project!

            The day after our experiment was supposed to be finished, it poured rain.  Frogs love rain.  So Brian asked for volunteers to go out one more night and survey all of the sites again.  I had practiced capturing frogs so much the prior night, but only caught one that contributed to our dataset.  So I geared up, this time in a full body bug net, and headed back out.  As soon as we got down to the road we could hear the Túngara frogs calling.  Every site was full of them, we caught 58 frogs for the night and I caught almost a quarter of them.  By the end of the second night, I was completely comfortable handling the frogs and would catch them for fun to try to identify their sex or just to watch them swim away after being released.  I even caught a large toad I saw along the road just to further examine it.  Having to catch frogs during my first week in Costa Rica was a great introduction to my OTS program.  It immediately forced me out of my comfort zone and taught me to not be afraid to try new things. I know that catching frogs is the first of many experiences that will push my comfort zone this semester in Costa Rica, and I can’t wait to see what direction I will be pulled next.