People are never neutral about snakes. Most people hate them, but biologists are usually thrilled to see them. We are lucky that our reserve caretakers, especially Luis Recalde, are among the very few local people who share biologists’ enthusiasm for snakes. They regularly find and photograph magnificent snakes, such as this arboreal venomous Bothriopsis species from our Rio Zunac Reserve, photographed by Luis. This is either Bothriopsis pulchra or Bothriopsis taeniata; we aren’t sure. These potentially deadly pit viper species are best distinguished by counting the number of belly scales (less than 200 in B. taeniata versus more than 200 in B. pulchra), but counting these didn’t seem like a good idea at the time. Most venomous snakes in the tropics stick to the hot lowlands, but this one reaches the mid-elevation cloud forests where most of our reserves are located. I have seen it at elevations as high as 1700m, and its congeners have been found as high as 3000m (Campbell and Lamar 2004). It eats small mammals, birds, lizards, and possibly tree frogs.
The adorable pit viper above, photographed in our Rio Anzu Reserve, is probably a juvenile of the same species. Snakes in this genus often change color as they grow older. If you look very closely (click image to enlarge it if needed) you will see that the tip of the tail is brownish rather than green like the rest of the body. This contrasting tail is wiggled as a lure to attract lizards or birds, which are eaten when they approach to investigate (Campbell and Lamar 2004).
The six or so members of the genus Bothriopsis have sometimes been placed in the genus Bothrops (which contains the dreaded fer-de-lance)., but recent DNA analysis by Fenwick et al. shows that the genus Bothriopsis is nested within Bothrops. That means some Bothrops species are more closely related to Bothriopsis than to other Bothrops. Nowadays we want our taxonomy to reflect evolutionary history, with close relatives grouped together, so this classification needs to be changed. Taxonomists can either call all of them “Bothrops”, or they can divide the tree into smaller genera (including Bothriopsis, and a reduced Bothrops).
These kinds of discussions about names may seem boring, but when we are dealing with poisonous snakes, they are a matter of life and death. More than 1000 people per year are bit by venomous snakes in Ecuador. Venom composition has an important phylogenetic component: close relatives have more similar venom than distant relatives. Antivenom for Bothriopsis species is scarce so there probably won’t be any available in the rural areas where bites are most likely. A local doctor faced with a patient bit by Bothriopsis will need to know the evolutionary relationships of the various pit vipers in order to choose from the available antivenoms.
Fenwick et al., recommend keeping Bothriopsis as a genus and splitting the remaining “Bothrops” into smaller genera. They show that the genera in this new classification are consistent with other well-established pit viper genera, in terms of within- and between-genera genetic distances (using cytochrome-b). This is similar to the argument that G. Salazar and I gave to justify our establishment of of the new orchid genus Quechua. We will use Fenwick et al’s proposed classification here. This taxonomy suggests that the widely available antivenom from Bothrops atrox and its close relatives would be a good bet for patients bit by a Bothriopsis.
But don’t worry, getting bit by a poisonous snake (or even seeing one) is extremely unlikely in any of our reserves, with the possible exception of the Rio Anzu Reserve, which is our lowest one. In that reserve we recommend people wear boots, and if you are lucky enough to see a snake, DON’T HURT IT. In all our reserves we also recommend that people stay on the trails, not so much because of snakes but to avoid damaging the vegetation and to avoid encounters with nests of bees or wasps. More on those in a future post….