Looking for toads in Peru

My work as a research assistant in the Peruvian cloud forest allowed me to experience herping (Looking for reptiles and amphibians) in a wet, forest location that I was previously unaccustomed to. When most people think of South America and the amazon, they immediately think of the extensive diversity of flora and fauna. Of course, there is more to the amazon than meets the eye and the vast jungles are more flora than fauna. The Amazon rainforest, making up 40 % of the South American Continent, ranges from north-western Brazil across parts of Bolivia, Peru, Ecuador, Colombia, Venezuela, Guyana, Suriname, and French Guiana. I was only able to experience a tiny part of it in central Peru but it was an experience to last a lifetime. At an altitude of 2200m in wet and cold conditions, the wildlife diversity can be limited, but amazing nonetheless.

My mission in Peru was a quite focused to find two species of toad, Rhinella yunga and Rhinella leptoscelis. Rhinella yunga has only recently (2014) been described as a new species and Rhinella leptoscelis was re-described as a species in 2009. For that reason, information regarding their behaviour and ecology is limited. As a research assistant, my duty was to find the eggs of these specific toads to observe the development of the ear membrane from egg to tadpole to adult. If no eggs were found, I was to find these species, keep them in an enclosure and “encourage” them to breed. If they bred, we would be able to observe egg development and note all the changing characteristics.

Day and night, I would go into the forest on my own (sometimes with a friend), searching high and low for frogs and toads and only on rare occasions return successfully with a toad or tadpoles of another species. In comparison to species rich areas this was quite a contrast. On occasion, I would hear the croaks of frogs but they weren’t quite the species I was looking for. Although, I did get to hear the glass frog, a transparent frog that I had only seen in photographs. I also learnt that it is much more difficult to find cryptic species with a limited number of people. When I did find a few species of both toads I had been searching for, I made a list of the differences and similarities between the two. I looked for the notable differences on the two toads, consulting the literature as a guide, making it easier to differentiate the two when I was in the field. The most notable difference was the round tympanic membrane evident on R. leptoscelis which is absent on R. yunga.

As the dry season started to set in (late April- May), things started to look more hopeful. One beautiful, sunny day, my friend and I went to the river to search for eggs. Imagine our excitement when we finally found little tadpoles on the edge of the river bank. There were hundreds of them moving along slowly down the river and so began my quest to collect as many as I could. The tadpoles were a few days old and we suspected that the eggs were laid higher up in the national park. This explained why we had not seen any eggs by the river close to us. At that point it didn’t matter, we were just happy to have found tadpoles. We proceeded to put them in the aquarium at the research station and identified them as R. leptoscelis. I continued to monitor the species until the day I left my position as a research assistant and said Goodbye to wonderful Peru.

Studies like this lead to the exploration of new niches and the understanding of how ecosystems work in different parts of the world. I am truly grateful I had that experience (even if it was for a short time of two months) and I look forward to many more research expeditions and adventures.

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