Octodon pacificus seen alive for the first time in 65 years.

Octodon pacificus is one of the relatives of the Octodon degus (common degus), which is commonly found in our homes. In total, there are five members of the octodon genus. The Octodon pacificus is considered critically endangered⁰¹, and the last individuals were found dead in 2016⁰². The last live sighting of the Octodon pacificus before these individuals were rediscovered dates back to 1959, when the species was described by zoologist Rainer Hutterer^{03 04}.

On March 19th, 2024, Julian Reyes García, head of the Biological Diversity Conservation Section of Conaf⁰⁵, along with student researchers from the University of Chile, captured live Octodon pacificus individuals. This discovery was made possible through several years of collaboration between the two entities. After analyzing the captured specimens, it was confirmed that they were indeed Octodon pacificus, a species found exclusively on Mocha Island.

A fragile and threatened ecosystem

Rodents play a crucial role in the food chain and in protecting the ecosystems where they live. Julian Reyes García explains that the Octodon pacificus contributes to seed dispersal and controlling pest populations. According to him, finding this rare species indicates that the island’s ecosystem is healthy. The Mocha Island National Reserve thus ensures the protection of this fragile ecological balance.

The reappearance of the Octodon pacificus opens new opportunities for research and conservation. Paula Aravena, director of the Center for Wildlife Rehabilitation, emphasizes that education is a major challenge in protecting this species. Many people confuse local species with exotic or pest rodents. She stresses the importance of establishing effective conservation programs for endangered species, including the Octodon pacificus.

Flavio Espinoza, a professor at the Catholic University of Santísima Concepción, proposes creating specific management plans for the Octodon pacificus. This would include breeding in captivity and controlled reintroduction into its natural habitat to ensure the species’ survival.

The evolutionary characteristics of Octodon pacificus

Octodon pacificus has unique features compared to its continental counterparts, notably a significantly greater weight and size. According to the theory of island gigantism, some species develop larger traits when they colonize isolated islands. The specimens captured on Mocha Island weighed an average of 200 grams, almost twice as much as the Octodon species found on the continent.

This unexpected return of the Octodon pacificus offers new possibilities for studying the social behavior and evolution of the species in an island environment. Researchers are particularly curious to know if, like their continental counterparts, these rodents possess a complex and cooperative social structure.

This discovery opens up a vast field of scientific research on the Octodon pacificus, particularly to understand its behavior, its role in the ecosystem, and ways to protect it effectively. The Mocha Island National Reserve thus becomes a privileged study site for better understanding and preserving the unique biodiversity of this island.

The return of the Octodon pacificus is an exciting event for the scientific community and marks a new milestone in the conservation of Chile’s endemic species.

Sources

Translated and modified from : https://www.diarioconcepcion.cl/ciudad/2024/04/09/revelan-inedita-historia-detras-del-hallazgo-del-roedor-extinto-de-la-isla-mocha.html