A catcher in the rainforest

I have discovered that I possess a skill of which I was previously unaware. This particular skill is not something that I’ll be able to use much in the future; it’s not exactly the sort of thing that will bolster my resume for future job applications. It was a very useful skill this week, though, and I can say with confidence that we would’ve had a much harder time completing our Independent Project had I not discovered this hidden talent.

             Last week, we ran data collection for our Independent Projects. Jess and I did a behavioral study on the strawberry poison frog, Oophaga pumilio, this super little “jeans”-wearing frog. Our project ended up being a continuation on the research we did with Dr. Molly Cummings from University of Texas at Austin. She came to join us at La Selva and instructed us on the mate-choice and male-male competition systems in the strawberry poison frog. We learned that, although calling is the traditionally-researched mechanism for territoriality and mate choice in this species, the perceived brightness of these vividly-colored frogs appears to influence their social interactions as well. We decided to continue on the research we had started with her concerning brightness differences in male-male interactions, but added a female frog audience, to raise the stakes.

            To run this experiment, we decided to put males in a shared enclosure with a female visible in a separate compartment. This would allow us to observe the aggressive and de-escalatory behaviors of our males, while varying their brightness differences and whether a female was present. In order to get enough data to make our results statistically meaningful, we knew that we were going to have to run at least 60 trials. Given that we needed two to three frogs per trial, and each frog could only be used twice, we realized that we were going to need at least 90 frogs to complete our project.

            Thus, our Frog Hunting expeditions began. At 6:30 each morning, Jess and I armed ourselves with flagging tape, sharpies and plastic bags, and set off into the primary forest down the STR trail. Until I came to La Selva, I never knew that frog species could differ so significantly in the sounds of their calls, but now I am certain I will never quite get the sound of O. pumilio’s call to stop ringing in my ears. It sounds like a very small saw, or sandpapery chirps: chh chh chh. For two hours each morning, we walked slowly down the trail, trying to ignore our growing sweatiness, dirtiness, and collections of mosquito bites, listening for this call.

Each time I heard one, I would stand as still as possible, peering into the undergrowth until I could spot the vibrant red dot that was courageously declaring its territory ownership from a low perch or leaf litter pile. Catching was always a challenge. I would often crawl on hands and knees toward the target (diligently on the lookout for snakes, of course, often covering myself in rainforest soil as I tried to get close enough to make the move. The frog would wait deceptively long before hopping away. I could almost see him thinking, “I’m very obviously brightly colored. This dumb predator should realize that that means I don’t taste good. Maybe when she gets closer, she’ll realize I’m not good to eat...?”

Eventually, though, he would dive into the leaf litter, where I would almost certainly not be able to find him. As the days progressed, I got better and better at snatching them before they could make their daring escape. Soon, it was a rare frog that got away.

We needed to collect around 90 frogs in order to make our project statistically relevant. In the first three days, we collected 88 frogs. I discovered last week that I have a skill only useful in this highly-specific scenario, and that skill is poison frog catching. Out of the 88 frogs we captured, I caught 83.

Emily Sanford

Macalester College