A scientist and an educator

I am a biologist graduated at the Universidad Central de Venezuela. My research interests include natural history, Tropical ecology, invasion ecology, ethology, and conservation. I have been working for several years studying the behavioral ecology and conservation of large tropical reptiles of the llanos of Venezuela (my homeland). Most of my experience has been with green iguanas and green anacondas, but I have also worked with other reptiles such as the Orinoco crocodile, spectacled caiman, and green sea turtles. My current research is with anacondas; it was the topic of my dissertation at the University of Tennessee and is the topic of the book I recently published via Oxford University Press.

After graduation I taught a course of tropical ecology for Boston University for one year and then I worked making TV documentaries for National Geographic Television as a field correspondent during three years. Working with TV is a fairly demanding activity and certainly takes a lot of time from scientific activities. However, it gave me the opportunity of reaching a huge audience with the conservation message. I do have a strong teaching vocation and often I am torn between the possibilities of teaching in a regular school where I would have the opportunity to teach in depth a small group of students or of doing films in which I can reach a huge audience albeit in a much more superficial manner.

I worked at various colleges and universities while I was doing TV documentaries and I recently took a position at New Mexico Highlands University where I run the NMHU Vertebrate Ecology Lab and continue my research and teaching. We do have a Master program and NMHU. Students interested in working with me can contact me with a letter of interest. We teach variety of field courses, including a comprehensive program of Tropical Ecology that I have developed from my work with Boston University, the Organization for Tropical Studies, and the School for International Training.

A firefighter

Before getting into the career of biology I worked as a fireman for seven years at the Cuerpo de Bomberos Universitarios de Caracas. During this time I worked not only on emergency calls of all natures (Emergency Medicine, Save and Rescue, and Building and Forest fires being the most common) but also in education and instructing the community in dealing with emergencies. Since the people from the community are the first ones to react to any emergency, we did substantial work in educating the community in effective emergency procedures.

The last year of my service in the fire department I was the Commander Chief of the station. Then I was faced with a fireman carrier which would had demanded that I lived in a large city or finish my degree in biology and work with wildlife and nature. It was a tough decision since my heart was equally split in both directions. However, I considered that there would be always people willing to help and protect people, while the same cannot be said for the environment. I resigned to my fireman carrier and went to the llanos to work with wildlife. My experience as a fireman taught me things about conservation that I would have never learned in an academic setting. It put me in contact with the harsh social reality of the large city and led me further into my interest in nature and the study of the secret life of animals. It also taught me that the solutions to conservation problems, among other social issues, cannot be accomplished with shortsighted programs attempting to attack one or just a few dimensions of the whole problem.

I am deeply concerned about habitat degradation and human activities that affect the well-being of other animals. I believe that until we offer real solutions for people that live in rural areas to live in harmony with nature we will continue to sink in our current environmental crisis. I am a firm advocate for conservation education at both the early grades and at the college level.

A Conservationist

I also believe that if we are to succeed in the campaign for habitat conservation it will not be by using a whole lot more of technology, but by using a little bit more of common sense. We hear a lot about research projects that cost half a million dollars to assess the need to protect a piece of Ecuadorian cloud forest that would cost $100K to buy and protect in perpetuity. To really address the issues we need to reach out beyond the boundaries of biology and science and adventure into the domains of things that most biologists no nothing about. I am talking about economics, political as well as social issues.

In my opinion the only way to work effectively in conservation is by working actively in education of the masses, guiding them to demand from their elected officials the right measures to protect the environment. Of course, like any other conservationist, I find it disheartening that, while a few of us work trying to save a piece of the planet, there are so many interests trying to destroy it all. Until we have a war-free world the is not much we can accomplish in the conservation arena.

Unfortunately the nations of the world do not seem to be heading in that direction for a long shot. There is no path to peace; peace is the path. I find working in scientific research fascinating and a source of new challenges every day. However, lately I am a bit turned off by the emphasis in many scientific trends to have ever close-minded approaches to understand nature and more and more reductionist interpretations. Sometimes some scientific positions can be so extreme that they are nothing short of religious fundamentalism, often ignoring our own biases when we do science. My preferred way to do science is by collecting original data in the field in wild animals and to look for new trends and new interpretations.

This is the reason that I spend a lot of my free time advocating about issues that most people is just dirty politics.   However there is no progress to be made in conservation unless those political issues are addressed. 

Peer-Reviewed Publications

Book Chapters

Mudrek, J., Figueiredo- Conceição, Brown, E., Rivas, J.A., Strüssmann T. 2019 Pesquisa e Conservação de crocodilianos no Centro-Oeste do Brasil. In Tratado de Crocodilianos do Brasil. In press

Rivas, J. A. 2009. How I Survived Killer Bees. pp.68-69. In: Michael Sweeney, (Ed.), Complete Survival Manual, National Geographic, Washington DC.

Rivas, J. Muñoz, M, Burghardt, G. and J Thorbjarnarson 2007. Sexual size dimorphism and mating system of the Green Anaconda (Eunectes murinus). pp: 312-325 In: R. W. Henderson, R. and Powell, G. W. (eds.), Biology of Boas, Pythons, and Related Taxa. Eagle Mountain Publishing Company, Eagle Mountain.

Rivas, J. A., M. d. C. Muñoz, J. B. Thorbjarnarson, G. M. Burghardt, W. Holmstrom, and P. Calle. 2007. Natural History of the green anacondas (Eunectes murinus) in the Venezuelan llanos. pp: 128-138. In: R. W. Henderson, and R. Powell, (eds.), Biology of Boas, Pythons, and Related Taxa. Eagle Mountain Publishing Company, Eagle Mountain.

Rivas, J. A. and Levin, L. 2002. Sex differential antipredator behavior in juvenile green iguanas, Iguana iguana: evidences for fraternal care. pp: 119-126. In Behavior, Diversity, and Conservation of Iguanas (Alberts, A. C., R. L. Carter, W. K. Hayes, and E. P. Martins, Eds.) University of California Press, Berkeley.

Rivas, J. A., Rodriguez, J. V., and C. G. Mittermeier 2002. The llanos. pp: 265-273. In Mittermeier, R.A. (ed.) Wildernesses. CEMEX, Mexico.

Rivas, J. A. and G. M. Burghardt. 2002. Crotalomorphism: A metaphor to understand anthropomorphism by omission. pp: 9- 17. In The Cognitive Animal: Empirical and Theoretical Perspectives on Animal Cognition. (Bekoff, M., Colin, A. and G. M. Burghardt, eds.) MIT Press, Cambridge, MA Journal Articles

Journal Articles

Rivas, J. A. (2020). Climate changes and speciation pulses in a nearly flooded continent: tackling the riddle of South America’ s high diversity. Ecotrópicos, 32, 1–21.

Smaniotto, N, Moreira, L. Rivas, J. A. and C. Strüssmann. 2020. Home range size, movement, and habitat use of yellow anacondas, Eunectes notaeus. Salamandra 56: 159-167.

De la Quintana, P. Rivas, J. A. Valdivia, F. and L. F. Pacheco. 2018. Eunectes murinus (Green anaconda): Dry season Home Range. Herpetological Review. 49: 546-547

De la Quintana, P. Rivas, J. A. Valdivia, F. and L. F. Pacheco. 2017. Home range and habitat use of Beni Anacondas (Eunectes beniensis) in Bolivia. Amphibia-Reptilia. 38: 547-553 (DOI:10.1163/15685381-00003124).

Rivas, J. A., Molina, C. R., Corey-Rivas, S. J., and G. M. Burghardt. 2016. Natural History of Neonatal Green Anacondas (Eunectes murinus): A Chip off the Old Block. Copeia: 402-410.

Dunbar, J. P. Zarelli, M., Martin, S. A., Gandola, R. Kavanagh, K. A. Walsh, F. M. and Rivas, J. A. 2015 Trunk vertebrae osteomyelitis in a spectacled caiman (Caiman crocodilus). Herpetological Bulletin 134: 15-18.

De La Quintana, P., Pacheco, L,. J. A. Rivas. 2011. Eunectes beniensis: Cannibalism. Herpetological Review 42:614.

Rivas, J. A. 2010. Is Wildlife Management Business or Conservation: A Question of Ideology. Reptiles and Amphibians 17: 112-115.

Rivas, J. A. & S. J. Corey. 2008 Eunectes murinus (green anaconda). Longevity. Herpetological Review. 39: 469.

Rivas, J. A. 2008. Ticks (Amblyomma spp.) on Black Iguanas (Ctenosaura similis) in Costa Rica. Iguana. 15: 25-27.

Rivas, J. A.; Ascanio R. & M. D Muñoz. 2008. What is the length of a snake? Contemporary Herpetology. 2008(2): 1-3

Rivas, J. A. 2007 Conservation of Anacondas: How Tylenol Conservation and Macroeconomics Threaten the Survival of the World’s Largest Snake. Iguana. 14:10-21.

Rivas J. A. and G. M. Burghardt 2005. Snake mating systems, behavior, and evolution: The revisionary implications of recent findings. Journal of Comparative Psychology 119: 447-454 Rivas, J. A. 2004. Eunectes murinus (green anaconda): Subduing behavior. Herpetological Review 35(1): 66-67.

White, J. M. and J. A. Rivas, 2003. Paleosuchus trigonatus (Dwarf Caiman) Neonate time budget. Herpetological Review. 34 (2): 141.

Rivas, J. A. and S. Kane. 2003. Pseustes sulphureus (Amazon Puffing Snake): Diet Herpetological Review. 34 (1): 72.

Rivas, J. A. and R. Y. Owens 2002. Crocodylus intermedius (Orinoco crocodile): age at first reproduction Herpetological Review. 33(3): 203.

Calle, P. P.. Rivas J. A. Muñoz, M. C. Thorbjarnarson, J. B. Holmstrom, W. and W. B. Karesh. 2001. Infectious Disease serologic survey in free-ranging Venezuelan anacondas (Eunectes murinus). Journal of Zoo and Wildlife Medicine 32(3): 320-323

Rivas, J. A., Aktay, S. A. and R. Y. Owens. 2001 Paleosuchus trigonatus (Schneider’s Smooth-fronted Caiman): Nesting and hatching Herpetological Review. 32: 251.

Rivas, J. A. and Burghardt G. M. 2001 Sexual size dimorphism in snakes: wearing the snake’s shoes. Animal Behaviour. 62(3): F1-F6.

Rivas, J. A. 2001. Feasibility and efficiency of transmitter force-feeding in studying the reproductive biology of large snakes. Herpetological Natural History. 8(1): 93-95.

Rivas, J. A., Owens R. Y. and P. P. Calle. 2001. Eunectes murinus: Juvenile predation. Herpetological Review. 32 (2): 107-108.

Rivas, J. A. and R. Y. Owens. 2000. Eunectes murinus (green anaconda): cannibalism. Herpetological Review. 31(1):44-45.

Rivas, J. A., Thorbjarnarson, J. B., Owens, R. Y and M. C, Muñoz, 1999 Eunectes murinus: caiman predation. Herpetological Review. 30 (2): 101

Rivas, J. A. and R. Y. Owens. 1999. Teaching conservation effectively: a lesson from life history strategies. Conservation Biology. 13 (2): 453-454

Rivas, J. A. 1998. Predatory attack of a green anaconda (Eunectes murinus) on an adult human. Herpetological Natural History Vol. 6(2): 157-159.

Rivas, J. A. 1998. The miracle of universities. Conservation Biology. Vol 12(6): 1169-1170.

Rivas J. A., Molina, C.R., and Avila, T.M. 1998. Iguana iguana (Green iguana): Juvenile predation. Herpetological Review 29 (4): 238-239

Rivas, J. A. 1997 Natural history: hobby or science? Conservation Biology.: 11(3): 811-812.

Rivas J. A., Molina C. R. Ávila T. M. 1996. A non-flushing stomach wash techniques for large lizards. Herpetological Review. 27(2): 72-73

Raphael, B.L., Calle, P.P.; Karesh, W., Rivas, J. A., and D. Lawson. 1996. Technique for surgical implantation of transmitters in snakes. Proceedings of the Wildlife Disease Association. 1996: 82.

Rivas, J. A. and Ávila, T. M. 1996. Sex differences in hatchling Iguana iguana. Copeia. 1996: 219-221

Rivas, J. A., Muñoz M del C., Thorbjarnarson, J. B., Holmstrom, W. and Calle P. 1995. A safe method for handling large snakes in the field. Herpetological Review. 26: 138-139

Calle, P., Rivas, J., Muñoz M., Thorbjarnarson, J., Dierenfeld, E. Holmstrom, W. Braselton, E. and Karesh W. 1994. Health assessment of free-ranging anacondas (Eunectes murinus) in Venezuela. Journal of Zoo and Wildlife Medicine. 25: 53-62.

Books and Reports

Rivas, J. A. 2020. Anaconda: The secret life of the world’s largest snake. Oxford University Press.

Rivas, J. A. 2015. Natural history of the green anacondas, with emphasis on its Reproductive Biology. South Carolina: CreateSpace Independent Publishing Platform.

Thorbjarnarson, J., Rivas, J. and Muñoz M. 1995. Ecology and behavior of the anacondas in Venezuela. Technical Report to the National Geographic Society Committee for Research and Exploration.

Muñoz M. and Rivas J. 1994. Ecologia y Conservación de la anaconda (Eunectes murinus) en Venezuela, segundo Informe. Technical report to CITES

Rivas J. and Muñoz M. 1992 Ecologia y Conservación de la anaconda (Eunectes murinus) en Venezuela. Technical report to CITES. 78p.

Rivas J. 1991. Estudio de factibilidad del aprovechamiento racional del recurso iguana verde (Iguana iguana). 36p. Technical report to the Venezuelan Fish and Wildlife Service, Profauna.

Rivas, J. 1990. Dieta de la iguana verde (Iguana iguana) en los llanos centrales de Venezuela durante la estación seca. Unpublished thesis presented to the Universidad Central de Venezuela . 96p. 1990. Caracas, Venezuela.

Contact me

If you want to get a hold of me about learning about anacondas, or doing documentaries drop me a note

  If you are interested in graduate school under my direction contact me at my school email rivas@nmhu.edu

Message Sent!

Your message has been sent successfully, I hope to respond within 24 hours. You can also contact us through social media, links can be found below!