Dr. Jenkins Investigates the Snakes of the Pantanal



We quietly floated past hundreds of Spectacled Caiman (Caiman crocodilus) as we made our way up a small river in the Brazilian Pantanal. Most of the scientists on this expedition were eagerly watching the forest looking for Jaguars (Panthera onca), but I was scanning the shoreline looking for Yellow Anacondas (Eunectes notaeus). I had a long list of reptiles I was hoping to find on this trip and the Yellow Anaconda was among the species at the top of it. It was the dry season and the water of the Pantanal (one of the world’s largest wetlands) was concentrated in rivers and deeper swamps. I spent hours wading chest deep through wetlands searching for Anacondas. I saw Caiman swimming only 10 meters away but the Anacondas were difficult to find; over the course of the week long trip we only found three. Two were small, approximately 2 meters, and the third was larger, almost reaching 2.5-2.75 meters in length. Yellow Anacondas are smaller than the more widely known Green Anaconda and it would be rare to find one over 3 meters.  However, both of these species have a similar ecology; Anaconda are an aquatic snakes that can be found on land but they spend the majority of their time either fully submerged or with only small portions of their body at the surface. The eyes and nostrils of Anaconda are located on the tops of their heads so they can remain mostly submerged as they hunt wetland species such as the Capybara (Hydrochoerus hydrochaeris).


I spent time on the ranches of the property we were visiting, surveying terrestrial habitats for snakes. Over the course of the week, in addition to the Anaconda and many species of lizards and frogs, we found two Yellow-tailed Cribos (Drymarchon corais), a False Water Cobra (Hydrodynastes gigas), and four swamp snakes (Liophis reginae). We also interviewed ranch staff and confirmed the presence of two vipers on the ranch; the South American Rattlesnake (Crotalus durissus) and the Matto Grosse Lancehead (Bothrops mattogrossensis). Our next visit to the ranches will include a rigorous survey of viper species that will help Orianne and the IUCN Viper Specialist Group with our current efforts to assess the status of Latin American Vipers. We may also initiate focal ecological studies on Yellow-tailed Cribos to examine how well the corridor we were in is protecting them and how their ecology and natural history compares to our flagship species the closely related Eastern Indigo Snake (Drymarchon couperi).


The properties I visited are part of a project established by Panthera, a big cat conservation organization (www.panthera.org), to create one the largest corridors of Jaguar habitat. Approximately 200,000 acres of habitat have currently been protected and with continued efforts, two of the larger National Parks in the region will be connected. This will also protect the many species of reptiles found throughout the Pantanal region. In addition to many reptile species, I also had the rare privilege of seeing Jaguars mate in the wild. Almost an hour into our boat ride a small patch of yellow and black was spotted in the forest; we quickly cut the engines and drifted to a stop. We listened to the purrs of a female Jaguar as she vied for the male’s attention; a few minutes passed and the we heard an enormous roar that signaled the end of their copulation. We watched and listened for almost an hour. But it was close to our base camp that same night that I saw the real trophy of this trip, my first Yellow Anaconda.


The Pantanal is one of the largest wetlands in the world and one of our planets great wilderness areas. It is also an amazing place where reptiles from many of the ecosystems of South America come together. The Orianne Society is dedicated to the conservation of rare reptiles and amphibians including our flagship species the Eastern Indigo Snake. As we continue to develop and implement programs to save Indigo Snakes in the wild, we will expand our efforts to understand and protect other Drymarchon species and the Pantanal will be an important place in this effort. Please visit us at www.oriannesociety.org and make the decision to help save rare reptiles and amphibians by supporting our efforts.