Dominical Costa Rica

By Quetzal Dwyer and Monica Perez

Throughout history serpents have repeatedly generated strong reactions, ranging from aversion and fear, to wonder and even veneration. Unfortunately, these enigmatic and often beautiful creatures are widely regarded as pests and many are currently vulnerable to extinction due to widespread habitat destruction and persecution by humans. Nevertheless, snakes play diverse and important roles in many terrestrial, aquatic and marine ecosystems, as well as in human culture. Human relationships with snakes have preceded written history by several million years, extending culturally and perhaps genetically back through our common ancestors. Now, in the twenty-first century, people variously treat snakes as vermin; merchandise in the food, leather, and pet trades; components of spiritual ceremonies and wilderness appreciation; and subjects of scientific research. Not everyone will learn to “like” snakes; however, recognizing the special ways that snakes interact with the environment can lessen our fear and broaden our empathy for all living things. This issue we will focus on one snake that occurs here in the Southern Pacific Zone which performs an amazing service. It feasts on venomous pit vipers!

Marvelous mussurana: this snake could save your life
Mussurana or Clelia clelia, is one of the few snakes occasionally recognized as useful by snake-phobic Latin Americans. Many nature-savvy campesinos-- local field workers and farmers-- acknowledge the benefit of leaving this snake alone. This is due to the fact that its diet consists primarily of other snakes, including venomous neo-tropical pit vipers such as the terciopelo, otherwise known as fer-de-lance (bothrops asper). In the 1930’s a Brazilian plan to raise and release large numbers of mussurana as viper control faded out due to several impracticalities. Nevertheless, the Butantan Institute in Brazil, which produces antivenins, erected a statue of Clelia clelia as a tribute to its assistance in combating venomous snakebites. Unfortunately, here in Costa Rica many people are afraid of this large and harmless snake and kill it on sight, ironically destroying a species that helps control the populations of a much more hazardous pit viper! Once again, learning to view snakes as ecological associates could help us to co-exist more comfortably and gain a greater appreciation of the complex life systems that we are a part of.
Serpent noir: black is back

Largely active at night, adult Clelia clelia-- also known as “zopilota” in Spanish-- are large, blue-black to dark gray snakes with paler bellies. Except for their underside the adults are uniform in color. However the juveniles—smaller, younger snakes of no more than around 24 inches-- have a striking red body with a distinct yellow collar around the neck and a black head. As these younger snakes age, the red is gradually replaced by black or slate-gray until they reach the uniform color of adults. Mussurana have a roundish, muscular body with smooth, shiny scales and a short head, not much wider than the neck. The eyes are small and black. Mature mussurana can grow to a total length of 8 feet! Although not considered dangerous to humans, the mussurana is a rear-fanged snake and does have mild toxin-producing glands. Apparently, these animals have developed an immunity to the venoms of Costa Rican pit vipers, including the terciopelo, which is their preferred food. They are known to be lethargic when handled and extremely reluctant to bite; nevertheless, we recommend that large individuals be cautiously approached. Better yet: let them be.

Mussurana are not as nomadic as many other snake species and tend to choose home-range territories. So if you see one of these sleek nocturnal vanguards prowling around your finca, thank your lucky stars! Consider them protectors, and hope they stick around.

Next Issue: We’ll take a closer look at the infamous terciopelo ….

Sources:
Leenders, Twan. A Guide to Amphibians and Reptiles of Costa Rica. 2001
Greene, Harry W. Snakes, the Evolution of Mystery in Nature

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