Rancho San Gregorio ~ Ecosystem

The Rancho lies within the Vizcaino Desert and protected area (Area de Proteccion de Flora y Fauna) known as the Valle de los Cirios (Valley of the Cirios) . This region has a uniquely rich distribution of flora and fauna, many of which are endemic species, that has made it a special region among those interested in desert ecology.

Surprisingly, in this harsh desert environment, visitors find thriving forests of cactus, succulents and trees. The abundance and diversity in the region makes for an amazing display of life adjusting to the environment. There are 39 endemic floral species in the protected area (León de la Luz et al. 1995; INE 2000; WWF and IUCN. 1994-1997). Among these are: pitaya, bishop's weed, old man cactus, perrenial herbs such as Cistanche deserticola. Threatened plant species include fan palms (Erythea armata, Washingtonia filifera, W. robusta) and tree yucca (Yucca valida) (INE 2000).

Some of the visual highlights of the fertile landscape are the barrel cactus, mesquite trees, agave plants and ocotillos.  However, without question, the visually dominate species in the environment are the cardon cactus and the cirios. These giants are a sight to behold.

Cirios, or boojum trees, are part of the ocotillo family and aside from a small colony in Sonora, Mexico are only found in this region. This most unusual plant, which to many resembles an upside down carrot, are most prevalent in the Vizcaino desert. The tallest specimens can reach heights of over 18 meters and are estimated to be over 350 years old. Cardon cactus are the true giants of the peninsula.  At the base, trunks can reach up to 1.5 meters thick and spread into several massive branches. These huge upsweeping branches allow this amazing species to reach heights of over 20 meters. Closely related to the Saguaro cactus of Arizona, they are nearly endemic to the region.

A couple of our most treasured evening activities begin for many as some of the most frightening. At dusk begins an amazing display that has been commonly referred to as the “bat show.” For about an hour, hundreds of bats come to drink from the pilla directly in front of the main palapa. The second involves going into the surrounding desert at night and looking for scorpions, which glow in black light. Our staff carefully “catch” the scorpions, which range from 1-5 cm in length, and allow students to get a safe, close look at these amazing arachnids. Soon, even the most wary traveler’s fears are transformed into awe and appreciation.

The area encompassing our two ranches is also home to the desert big horn sheep (Ovis canadensis cremnobates), called borregos by local people. The desert big horn sheep are a rare and amazing sight. Their population throughout Mexico is estimated at a mere 4000,  but these magnificent animals can often be seen in our area. Adult males known as rams can weigh between 150-200 pounds and ewes weigh between 100-125 pounds. Threatened by hunters willing to pay hundreds of thousands of US dollars for permission to kill one ram, borregos wage a battle for survival tougher than any of their daily treks over the steep rocky hillsides.

With the help of our kind and generous supporters, we continue our work to preserve and protect the area around Rancho San Gregorio and Rancho Aguaje as a refuge for all its inhabitants.


HOME | ABOUT | CONTACT | RANCHO SAN GREGORIO | VERMILION SEA FIELD STATION | MERCHANDISE & DONATE