Unveiling the Isabel Giant Rat on Mt. Sasari
Discoveries made by chance often lead to the most astonishing revelations. This was the case when scientists and local villagers explored Mt. Sasari, a remote cloud-forest plateau in the Solomon Islands. At their initial campsite, a young local boy stumbled upon a baby rat nestled at the base of a flowering Caryota palm. This was no ordinary rat—it was a juvenile Isabel giant rat, a species not seen by Western scientists for over thirty years.
The Marvel of Mt. Sasari’s Cloud Forest
Mt. Sasari, situated on the eastern end of Santa Isabel Island, stands as the island’s highest peak, reaching over 1,100 meters. This unique cloud forest is unlike any other on the third-largest island in the Solomon Islands, as noted by Peter Waldie, acting director of TNC’s Solomon Islands program. Despite its smaller size compared to neighboring lowland forests, Mt. Sasari is a treasure trove of biodiversity.
Ecologist Patrick Pikacha, who led the survey, highlights the significance of the plateau’s geography. “The plateau of Mt. Sasari supports an extensive montane forest, offering a unique habitat for a wide array of species to evolve and thrive.” Unlike other jagged and volcanic mountains in the Solomons, Sasari’s flat summit provides ample room for species adaptation and evolution.
The Isabel Giant Rat: A Remarkable Discovery
At first, Pikacha and his team were unsure of the young rat’s significance. “We initially thought it was an invasive rat,” Pikacha says. “But closer inspection revealed it was not a Rattus rattus. It had a robust build, a flat nose, a long tail, and brown fur, distinguishing it from typical invasive species.” Its wide feet suggested it was arboreal.
Known scientifically as Solomys sapientis, the Isabel giant rat is among the rarest species in the Solomon Islands. Last documented in 1991, it is shrouded in mystery, with limited information available beyond related species like the Bougainville giant rat. Local communities, however, are familiar with the rat, known as kakahu, which they sometimes hunt and consume.
Rich Wildlife of Mt. Sasari
The survey team discovered a wealth of wildlife during their expedition. They encountered the northern common cuscus and several bat species, including the Solomons tube-nosed bat and the long-tongued nectar bat. The survey also recorded 6 reptile species, 15 bird species, and 19 frog species—a notable achievement for such a brief survey. Remarkably, Sasari is home to 42 orchid species, with 11 species found growing on a single tree.
Conservation Efforts for Mt. Sasari
This biological survey marks the first step towards securing long-term protection for Mt. Sasari’s forests and the habitat of the Isabel giant rat. Though detailed data on the rat’s population is lacking, the species is classified as endangered by the IUCN due to habitat loss and hunting. Reports from local communities indicate that the rat had become scarce by the early 1990s, a situation worsened by recent extensive logging.
Pikacha emphasizes the mountain’s importance to local communities, especially women with a matrilineal connection to the land. “Sasari is distinct due to its matrilineal ownership and the strong involvement of local women,” he notes. The Nature Conservancy aims to secure formal protected status for Mt. Sasari and to raise additional funds for further research and conservation efforts.
In conclusion, safeguarding Mt. Sasari’s unique ecosystems is vital for preserving rare species like the Isabel giant rat and maintaining the rich biodiversity of the Solomon Islands.
