Day 2 – When Night Falls

In the evening, I am excited to go on an ecology-focused hike with the Arenal Oasis company touting interaction with frogs, snakes, and other local wildlife. Apparently, not everyone gets as excited as I do, as I’m the only one waiting in the lobby a few minutes before 5:30. Gerald, the guide, picks me up at the hotel and we chat about the area. He informs me that people call the combination of much older, adjacent volcano called Cerro Chato and Arenal the sleeping Indian. In profile, the two volcanos appear to form a sleeping Indian with a sloping forehead, two lips and a chin, a bulbous belly, and Arenal forms the feet. I also find out that Gerald speaks excellent English because he had the opportunity to live with his aunt for two years in New York. The lack of a language barrier sets a precedent for the evening with a multitude of nerdy exchanges (I wish I could use the word “cerebral” here, but I think I need to call it what it is) on the local biota.

Arenal Oasis is an interesting project with an ecological conservation and sustainability bent. There are a series of cabins built over time that comprise their “eco-lodge” where guests can stay at their location in La Fortuna. The gardens are maintained organically. The night hike explores the nature reserve they’ve created on their property out of what was once a cattle field.

The night is thrilling. The sound scape sharpens in the rainforest as most of the wildlife is nocturnally active. We chat about the issue of invasive species (not as intense an issue as there is so much diversity, it’s hard for any one species to overtake an entire area) and Costa Rica’s attitude towards conservation (from what I gather, it’s much like a facebook status – “it’s complicated” but it appears there is some infrastructure for it ).

We start by exploring some of the local flora. There are local species of impatients which are similar to ones we have in the states. With a light touch, their seed pods burst open. It turns out, there is a small coil that is responsible for the pods breaking apart – a sort of naturally produced spring. Many of the plants here have broad leaves exhibiting countershading – green on the surface, deep maroon on the undersides, allowing them to absorb sunlight reflected off the ground. Others, like the plant locals commonly call “maracas”, have modified leaves meant to capture water opportunistically (Part of a Genus of plants called “Heliconias” that share similar characteristics). People have been known to shake the slightly ginger-smelling water from these plants and use the mixture as shampoo or as a natural insect repellent. Another similar, flattened version of the same adaptation is sported by a plant commonly called the “rattlesnake plant”. These plants also flower in stages from the base upward, allowing them to flower for upwards to a month, and making their resources last longer.

"Maracas" - a plant in the Heliconia Genus (

We also see some of the large flat leaves with careful incisions along their lateral lengths. Portions of them are now bowed into a tent of sorts, apparently due to the action of  local species of bats that use them as shelter. We see a toad hop by on the path. He hops away until he is certain we cannot see him, then freezes in a sense of mock security. Gerald explains the difference between toads and frogs – some of them obvious – scaly, drier skin, less aquatic – other less so – the presence of paratoid (poison) glands behind their eye sockets. (Apparently the distinction between these two groups on a scientific level is not always so straight-forward) Arenal Oasis has also set up a slew of terrarium exhibits along the pathway to showcase species from the area as well as other parts of Costa Rica.

Bats use many of the local species of plants for a place to sleep (

We start peaking at the tanks containing a series of frog species. Costa Rica has several types of poison arrow frogs, but they are hardly as toxic as those from other countries. They can cause numbness, tingling, mild sickness. They are delicate and beautiful, and quite minuscule – significantly smaller than expected. Several species are good examples of the effect of natural barriers on phenological features. There are several species on the opposite coast of the country that are visually very similar except for a different stripe of color or proportion of colors to one another.

We also discuss the different reproductive strategies of varied families of frogs – those that lay eggs in the water, on top of the water, in trees, or spread among varied locations in order to increase their progeny’s chance for survival. Some even go as far as carrying newly hatched tadpoles on their backs to more suitable habitat.  A Cane Toad looks menacingly from behind glass of one tank (see my previous post on Cane Toads) . There is another frog known as the chicken-eating frog who is known to on occasion eat itself to death due to what has been suggested to be a poor memory about the dinner it just consumed.

While we are looking at the first exhibit, it begins to rain – thunder and lightning bursting in the sky above. It’s the first time I begin to notice how nervous people in the region are when it comes to lightning. Rain phases few, but the lightning causes some worried looks to fleet across many of our guides’ faces. However, the storm allows the evening to take a strong biological turn. The level of sound rolls up a notch and animals start to come out in droves. We pass by the frog pond and see examples of many local species, including the red-eyed tree frog, one of the most photographed rainforest fauna – in essence becoming a sort of rainforest mascot.

Red-eyed Tree Frog (photo credit: Carrie Schuman)

Other forms of life are enjoying the rainfall which is apparently essential to the flow of nutrients from the tree canopy to the forest floor. Snakes are delicately coiled among overhead branches, one of the reasons it is a poor choice to indiscriminately pull at branches without first glancing at what you are touching. We see an eyelash viper, one of Costa Rica’s poisonous species overhead. They are present in multiple color variations and utilize differing habitat space within their ecosystem. We see a lovely little black and white snake overhead elegantly coiling in and out of itself (I later determine this was most likely a coral snake).

The insects are fully active as well. A female katydid with an ovipositor the length of its body quietly sits under a branch while a nearby terrifyingly large spider launches itself, swinging back and forth in its attempt to capture the nearby bug. A bullet ant crawls along the length of a stem. They are called bullet ants not because of their size but because of the pain of their sting.

We quickly lose track of time as we both chat about the biology and fascinating things about the area. On the ride back home, I ask about the tourism in the area and what things have been like since the volcano has gone dormant. La Fortuna has only become a player in the country’s tourist game somewhere in the space of the last 30 years or so, but it’s interesting their future is based upon an ecological phenomenon with such an unstable and unpredictable nature. I hope they are able to continue sharing the awe-inspiring beauty of the rainforest there for some time to come.


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