Notes from the Field: La Selva, Costa Rica

There is a subtle sour smell of sweat. It has permeated all of my belongings. I have been in the lowland rainforest of Costa Rica for just about two months. It rains constantly here, making sure everything has a perpetually clammy, slightly damp feel. I have been here catching fruit eating bats for a collaborative project with my advisor. We are investigating the coevolution of fruit scents in piper plants and the diet of a genus of bats, Carollia spp.

Piper is highly diverse and rampant genus of plants. There are ca. 1,000-2,000 species worldwide and about 50 of them can be found in the La Selva Biological reserve. The first month, I scrambled around the forest picking leaves of anything and everything I thought was piper. At first, it was extremely challenging because you think you know what Piper looks like and then BAM! you realize there is so much variability in traits for within one species. Even across different species you can have everything from heart shaped leaves to round to smooth to hairy leaves. You have species that can only be positively identified by smell, “Smells like lemons, must be Piper xanthstachyum!” or even species you have to identify by taste “Oh shit, my tongue is numb, must be Piper darienese!”

Piper diversity
Piper diversity

However, it has become kind of fun, like a super hard version of “Where’s Waldo?”. Except, instead of Waldo you have 50 species of plants that look like everything else in the forest and instead of a two-page book spread you are in 1,600 hectares of jungle!


In the evenings, I mist-net trying to catch the species that are feeding on these plants, Carollia castanea, Carollia sowelli, and Carollia perspicillata. These species are relatively abundant so most nights we catch at least a few. However, these aren’t the only species that are eating the Piper. The other night we caught Dermanura watsoni (Thomas’s fruit-eating bat), with a Piper in the net! Be that as it may, the Carollia bats are the real specialists at eating Piper.

Dermanura eating Piper
Dermanura watsoni eating Piper (photo credit Ada Kaliszewska)

Every night is a challenge, an adventure and sometimes a success! We have one more month of sampling to go and the rains are starting heavy again. Wish us luck!






Some other fun creatures of the forest…






Notes from the field: La Selva…and then the rains came

Two flashes of lightening, I am subconsciously counting the seconds…until a loud clap of thunder rolls through the clouds above. With all this I am still unsure if it is going to rain. I teeter between packing up my gear to sprint to the nearest shelter or try to wait it out. If the rain does come I will only have seconds to get to shelter before it hits hard.

I stand. I wait. I listen. All of a sudden I hear the Howler monkeys scream their loud whooping calls as they protest the impending rain. Then I know it’s about to rain and hard. I scramble to pack up my equipment and samples and after a minute I am drenched. This is life in the rainforest.

I have been here for a little over two months and I am finally starting to understand the voice of the jungle. When I first arrived it was overwhelming, so much so, that I felt I couldn’t hear or see anything even though with every step I took I passed dozens of species. It’s like getting to know a new friend, you learn how to read them. Read the cues of their behavior and read their moods. This rainforest is definitely a moody one. The weather is capricious, especially as we enter December. One minute the rain will be pouring down so hard you have to shout over it and then, all of a sudden, the sun will break through, hot and strong. The water will immediately start evaporating and you can see the steam rising from the ground all around you. While this can make field work challenging it also makes this place surreal and magical.Drenched, but still working