For many years he has acted as scientific adviser for the BBC and the National Geographic Society. Regional Editor of the United Nations' Global Environmental Outlook ("GEO Report"). He has been a researcher at the Smithsonian Tropical Research Institute, the National Museum of Costa Rica, the University of Costa Rica and the Distance Education University of Costa Rica. He has also done research as part of teams with the USDA (USA), Uppsala University (Sweden), University of New South Wales (Australia) and the Nanjing Institute of Geology and Paleontology (China). He is Curator of the Encyclopedia of Life (USA) and Team Member of the IUCN Red List of Threatened Species (Switzerland).

From Wikipedia:

“Monge-Nájera was for 25 years the Editor of Revista de Biología Tropical. He started his career studying tropical freshwater turtles and then moved to freshwater snails (Physidae). He described the vertical movements of the snails in the water column and the presence of two trematode parasite species in the tissues. He also described the egg capsules, embryo development and presence of oligochaete worms on the snail body surface.

He published a detailed study on Hamadryas butterflies that analyzed their use of trees as territories and the why and how of sound production. This study solved some old questions that had been made but left unanswered by Charles Darwin in his Journal of Researches and in The Descent of Man and Selection in Relation to Sex. His discoveries with butterflies were mentioned in National Geographic Magazine and The Readers' Digest.

In the decade of 1990 he published several works on the behavior, ecology and biogeography of velvet worms (Onychophora). His studies included extant onychophorans and fossil species that lived in marine Cambrian communities. These studies were coauthored with Hou Xianguang. In the same period, Monge-Nájera produced several articles on the use of computers and Internet for distance education.”

BBC Trials Life. 1987
BBC Trials Life. 1987

He is author or co-author of 20 books published by several Costa Rican universities, Oxford University, the National Biodiversity Institute (INBio) and Tropical Nature Press. He has written nearly 60 specialized papers about tropical ecology, biogeography and evolution, as well as about applied ecology (pollution and pests) and distance education, in international journals published in Europe, Costa Rica and the USA, including the prestigious Linnean Society of London. He also authored about 50 educational papers, a hundred essays and 30 scientific meeting papers as well as many Internet web pages.

He has been editor in chief of Revista de Biología Tropical, Brenesia, Boletín de Biotecnología, Medicina Legal, Paz y Ambiente, Revista Latinoamericana de Derecho Médico y Medicina Legal, and Odontología Actual,as well as editor for several INBio books. He has taught Research Methods, History of Biological Thought, Scientific Photography, General Biology and Bioethics in public and private universities.

Editorial board member of the following publications: Verde (Mexico, D.F.), Historia Naturalis (Río de Janeiro, Brazil), Gayana (Chile) and Biología Tropical, Biocenosis, Lankesteriana and Repertorio Científico (Costa Rica). Scientific reviewer for Five Kingdoms, by L. Margulis and K. V. Schwartz (Freeman, N. York, 1998). In 1996 elected Member of the Société de Biogeographie, Paris, and member of the Costa Rican Ombudsman Academic Advisory Board and of the Scientific Advisory Board of the Wilson Botanical Garden, Organization for Tropical Studies. Honorary Member, American Biographical Institute Research Board of Advisors. The Parisian Courrier published his essay on Internet for the net's 25th anniversay.

In 1997 his biography was added to Who's Who in the World, followed by the Dictionary of International Biography of Cambridge in 1998, Outstanding People of the 20th Century in 2001, and 2000 Outstanding Intellectuals of the 21st Century in 2002. Former Director of Academic Production at UNED. An invertebrate species has been named in his honor in the Paris Natural History Museum. He lives with his family on the side of Irazu Volcano, Costa Rica. His hobbies are nature and figure photography, as well as drawing and writing.