Sima de las Cotorras

What is Sima de las Cotorras?

Sima de las Cotorras, which translates to "Sinkhole of the Parrots" or "Sinkhole of the Parakeets," is a prominent geological formation located within the El Ocote Biosphere Reserve in the western part of Chiapas, southern Mexico. It is a large, vertical sinkhole formed by the complex interplay of tectonic forces and erosive processes acting upon the region's limestone bedrock. While not the largest or deepest sinkhole in the area, Sima de las Cotorras is particularly renowned for its vibrant ecosystem and its role as a sanctuary for thousands of Mexican green parakeets.

Geology and Formation

The sinkhole is a product of karst topography, a landscape characterized by dissolution of soluble rocks like limestone. Tectonic movements in the Sierra Madre de Chiapas, involving the folding and fracturing of the relatively soft limestone, created weaknesses in the rock. Water, both on the surface and underground, then eroded these fractures over thousands of years, leading to the eventual collapse of the overlying rock and the formation of the sinkhole's deep, vertical shaft. The sinkhole's opening is elliptical, with varying rim elevations, and its walls reveal distinct geological layers, with stalactites and stalagmites visible about 70 meters down.

Biodiversity and Ecosystem

What sets Sima de las Cotorras apart is the unique tropical deciduous rainforest that thrives at its bottom, creating a microclimate distinct from the surrounding drier grasslands and shrublands. This lush interior is home to plant species not found elsewhere in the region. The sinkhole's most famous inhabitants are the Mexican green parakeets (Psittacara holochlorus), an endangered species, numbering an estimated 3,000 individuals. These birds congregate in the sinkhole for much of the year, using its sheltered environment as a nesting site. The sinkhole also supports a variety of other wildlife, including various bird species, mammals, and reptiles.

Cultural and Ecotourism Significance

Evidence of human presence in the area dates back at least 7,500 years, with significant archaeological finds including approximately 75 cave paintings, arrowheads, and pottery shards. The cave paintings, found high on the sinkhole walls, are a rare and important cultural heritage. In 1985, the Sima de Cotorras Ecotourism Center was established to offer local Zoque families an alternative source of income, promote environmental conservation, and deter migration from the area. The center provides visitors with access to the sinkhole, including guided tours to see the cave paintings, the unique flora, and the parakeets, as well as opportunities for rappelling. Despite efforts to balance ecological preservation with economic viability, the site faces challenges related to promotion and accessibility, with most visitors being local day-trippers drawn by the spectacle of the parrots.