Lizard Hunting in a Swollen Stream

By Tyus Loman

          Today was the first day of our faculty led projects in the Estación Biológica Las Cruces. four OTS students, including myself, and Mau, set out on a gloomy morning in search of anoles, led by Michelle Thompson, an ecologist who had been studying amphibians and reptiles in Costa Rica for her Ph.D. The task for the day was simple: find anoles, capture anoles, mark the capture site, take them back to the lab to measure and record data describing morphological.

We had hiked trails at Las Cruces over the last week, and we had easily found plenty of anoles. On this day, however, conditions would not allow for such easy anole collection. That morning brought the first morning rain since we had been there, starting with a strong drizzle at 7:30 am. The rain itself was not upsetting; however, it would make most anoles difficult to find. We split up into groups of two, searching the dense vegetation on the sides of the trails to no avail. There were no signs of anoles, most of us failing to even spot a frog. The small, cold-blooded vertebrates were too susceptible to the cold temperatures to be out on a morning like this. Still we hiked on, continuing to go off-trail to search for the small lizards as the rain picked up. 

           After around two hours of unsuccessful anole searching, Michelle decided to change the experimental design. Previously, she had studied stream-dwelling anoles called Norops oxylophus while doing research in La Selva. She was aware that a closely-related species to N. oxylophus could be found in Las Cruces, a species called Norops aquaticus that also dwelled on perches near streams. We chose to leave the dense vegetation and head for the streams.

            Split into groups of three, each group searched a different part of the stream. My group closely examined rock walls and other perching sites for the aquatic anoles. As we walked downstream, things were relatively easy. Outside of the occasional slippery rock, we could generally avoid falling into the stream. My colleagues found a few anoles, while my grand total of anole sightings remained at zero. Still, the entire time we searched the rain came down harder and harder. On the way back upstream, the stream had swelled massively, increasing the flow strength and the difficulty of maintaining balance. The water level rose by about two feet, and rocks I had used as foot holds were now completely submerged. On a couple occasions, I slipped and fell into the stream, completely submerged under the water. Still, I had not captured a single anole, but my colleagues found enough to compensate for me.

              Eventually we made our way back to the research station, thirty minutes late for lunch and completely drenched from head to toe. Still, despite my lack of success and the non-ideal weather conditions, I found myself to be in good spirits. As someone who has lived his entire life near the ocean, I have always had great affinity for water. Even though the stream was not much of a swimming hole, just the idea of being in water was enough to lift my spirits. No matter the conditions, I am a water mammal. As well, the stream and other bodies of water serve as habitats to a multitude of different plant and animal species. The entire experience reaffirmed my belief in ecological conservation. As people, we should always work to preserve these wonderful ecosystems, along with the rest of nature that most people do not get to experience.