Armando Castellanos took his first steps as a biologist in Sangay National Park in 1991 studying the mountain tapir, Tapirus pinchaque. A few years later, he began his research with the Andean bear, Tremarctos ornatus, embarking on a long process of empirical learning after which he wrote the first version of the "Guide for the Rehabilitation, Release and Monitoring of Andean Bears" in 2005, after 15 years of research.

After dedicating two decades exclusively to the study of the spectacled bear, Armando resumed projects involved with the study of the Andean tapir in 2010 in the moorlands of Cayambe Coca National Park, where he placed satellite collars on 9 specimens. In 2016, he signed a research agreement with Cheyenne Mountain Zoo, Los Angeles Zoo and Smithsonian Conservation Biology Institute, for which 12 Andean tapirs were radio collared. Within this ongoing research project, the objectives were to study reproduction, blood levels, serology, and iron levels in the blood of Ecuadorian populations of this species.

To date, Armando has tagged a total of 30 wild Andean bears with radio collars and satellite collars, and has successfully reintroduced 22 of these specimens to their natural habitat. He has also captured 48 Andean tapirs and recaptured them 15 times, with the purpose of replacing old or defective collars to increase the quantity and quality of tracking data.

The extensive list of scientific publications that have emerged as a result of years of monitoring and data analysis of these animals include mostly articles on the Andean bear, followed by the mountain tapir and in recent years have included the páramo wolf.  

The Andean bear and mountain tapir research conducted by Armando has been supported by organizations such as: International Association for Bear Research and Management (IBA), World Society for the Protection of Animals (WSPA), Wildlife Conservation Society, Zoo Conservation Outreach Group (ZCOG), Cheyenne Mountain Zoo, Los Angeles Zoo, Cleveland Zoo, Parco Natura Viva, A.R.C.A. Foundation(Animal Research and Conservation in Action) of Italy and National Geographic.

The Andean Bear Project directed by Armando, now called Great Mammals of Ecuador, has been filmed for documentaries by the BBC, National Geographic, BR of Germany, and NHZ of New Zealand.

To date, Armando has given 18 face-to-face and online telemetry workshops on data management and ecology of large mammals for biology and related careers students both nationally and internationally. Armando has taken a holistic view of Andean bear conservation, implemented several initiatives to mitigate the bear-human conflict, for example compensated for corn eaten by bears in the area of Intag, Imbabura Province, has signed a compensation agreement with the community of Oyacachi for losses of cattle due to bear predation, soon with the community of Pesillo. To date he has delivered 38 calves to those affected. Armando also offers research opportunities for young biologists to develop their skills and do their own scientific research on bears, tapirs and wolves.

You will find the name of Armando Castellanos in the list of assessors in the IUCN Red List evaluation of the mountain tapir as an endangered species. Armando is a Research Associate at the National Biodiversity Institute of Ecuador and the Biology Department of the National Polytechnic School.

Since 2019 Armando initiated the study of the páramo wolf, Andean fox, atuk(Lycalopex culpaeus) in Cayambe Coca National Park, Cotopaxi National Park and Pasochoa Reserve to study their movements by radiotelemetry and disease transmission with feral dogs, to date he has trapped 9 animals, 2 individuals were radio-tagged and one páramo wolf wore an Iridium/GPS collar. To date, three Andean foxes have been released: one at Hacienda Yanahurco, Napo Province; in 2020, two specimens were reintroduced: one in the upper part of Cayambe Coca National Park and the other near the Mojanda Lagoon; the two female wolves wear radio collars to monitor their adaptation to their new habitat.

In January 2021, Armando Castellanos and his team went to the Waorani community of Bameno, an intangible zone of Yasuní National Park, where they trapped and tagged a male tapir(Tapirus terrestris) with a satellite collar. Their next expedition is scheduled for January 2022.

On April 1, 2021, in the province of Sto Domingo de los Tsáchilas, Armando and a coalition of organizations and NGOs participated in the release of "Luli" the puma(Puma concolor), using a helicopter for the transfer and with the support of INABIO we placed a satellite collar for monitoring.